Supreem Circuits Diagram and Projects: Choice and Hobby

Build a Digital Stopwatch 0-60sec

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
Now Build a Digital Stopwatch 0-60sec By using the same circuit of the Digital Stopwatch 0-99sec , we can add  an AND gate, and transform the 0 – 99sec stopwatch to a 0 – 60sec  stopwatch.We must find a way to control the RESET function of the BCD  counter, which is responsible for the counting of the seconds. As we  studied above, the circuit resets when we have 99 to 100, that is 1001  1001 à 0001 0000 0000. To make a transformation successfully we must  force the pulse from 59 to 60 0011 1001 à 0100 0000 on the output of the  BCD counter.<br />
<br />
</div>
<div style="text-align: justify;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjU2iZ_6QCzR4VfVOj4agjvNPxvJm5iO3suLpegnXjc7DmHVlVCllqKjJ0MLCZkeY0HCZpXcSQwJcMb7xOZnuRATKsM9zOMSe6hG-74aU7LIHBqYsm2sva6uAuk59NlruQncBzoc7Ah7RGQ/s1600/schem+0+60_th.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="395" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjU2iZ_6QCzR4VfVOj4agjvNPxvJm5iO3suLpegnXjc7DmHVlVCllqKjJ0MLCZkeY0HCZpXcSQwJcMb7xOZnuRATKsM9zOMSe6hG-74aU7LIHBqYsm2sva6uAuk59NlruQncBzoc7Ah7RGQ/s400/schem+0+60_th.gif" width="400" /></a></div>
<div style="text-align: justify;">
<br />
<br />
By placing the AND gate, with its inputs on the Q1 and Q2 of the BCD  counter of the decades, we make sure that when the gate closes, the RST  input of the BCD counter will be set to logical “1”, which on its turn,  will force the circuit to start over. The transformed circuit appears in  picture 2.</div>
</div>

Build a Digital Stopwatch 0-60sec

Now Build a Digital Stopwatch 0-60sec By using the same circuit of the Digital Stopwatch 0-99sec , we can add an AND gate, and transform ...

4-Minute Shower Timer

Choice and Hobby 10:29

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
Gone are the days when we can afford to luxuriate under a hot shower for  hours on end. Well, maybe the showers weren’t quite that long but most  people are used to taking showers in the tens of minutes. It’s easy to  lose track of time in the shower. And it does feel nice.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
That’s a luxury that’s no longer economically nor ecologically  sustainable. First of all, we’re short of water. In most areas of  Australia the powers-that-be keep telling us if we don’t be good boys  and girls and cut our water usage then we are going to run out.<br />
<br />
(Those same powers [read politicians] that keep blaming us wasteful  consumers don’t mention that for the most part water shortages are their  fault, because they haven’t invested the necessary dollars in water  infrastructure while population has steadily increased for much of the  last half century. But let’s not get into that argument. At least not  right now . . .)<br />
<br />
Second, we’re short of electric power. The power that goes to heat the  water is also in very short supply. Load shedding (ie, blackouts!) is  becoming more and more common as supply authorities attempt to cut peak  loads. Those same powers-that-be keep telling us that if we don’t reduce  our consumption of power, it’s going to get worse. (Those same powers  [read politicians] that keep blaming us wasteful consumers, etc etc etc .  . .)</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Putting aside all the scare-mongering that’s going on in political  circles (my spell checker wanted to change that to circuses, which would  be perhaps more apt) it really does make sense for us, as consumers, to  try to save both water and power – if only because that means less of  our hard-earned dollars will end up in Government coffers.<br />
<br />
One way to do both, of course, is to take shorter showers. How short?<br />
<br />
<span style="font-size: medium;"><span style="font-weight: normal;">The 4-minute shower</span></span><br />
<br />
Believe it or not, it is entirely possible to take a shower in four  minutes – including, if you need to, washing your hair. In fact, without  shampooing, a sub-three-minute shower is perfectly practical. People in  the bush who don’t have the luxury of hot water have been "getting"  that sort of shower for years: get in, get wet, get clean, get out!<br />
<br />
Let’s face it – all you really need to do is get wet, soap up and rinse  off. Get wet: 30 seconds. Soap up: 60 seconds. Rinse off: 60 seconds.  That’s two and a half minutes. Add another 60 seconds to shampoo your  hair and there’s your four minute shower – with 30 seconds left over for  good measure.<br />
<br />
OK, if you agree that four minutes is enough time, how do you go about convincing everyone in your family?<br />
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<img alt="4-minute-shower-timer-circuits-diagrams 1" border="0" height="203" src="http://2.bp.blogspot.com/-RCSLRv9Y1iE/UL9MCEa_zgI/AAAAAAAAHV4/mAMtz6TjXDQ/s1600/103674_7mg.jpg" title="4-minute-shower-timer-circuits-diagrams 1" width="400" /></div>
<div style="text-align: justify;">
<br />
<span style="font-size: medium;">The ST4 Shower Timer</span><br />
<br />
This rather ingenious (and patented) design is completely automatic,  turning on about 20-30 seconds after it "hears" the first "sssshhh" of  the shower – giving you enough time to adjust the water temperature –  then beeping each minute up to the magic four minutes, at which time it  sounds an alarm.<br />
<br />
The alarm stops when you turn the shower off. But if you try to fool it  by turning the shower off for a moment and then back on again, the alarm  will start back up again. It resets after about a minute of  no-shower-sound, ready for the next person to take their shower.<br />
<br />
Part of the secret to this circuit is the use of the piezo buzzer: it is  not only sounds the beep/alarm, as you would expect but it is also used  as a "microphone" to pick up the splash sound.<br />
<br />
There’s no on-off switch; it simply operates when it hears the shower  turn on (listening for the distinctive splashing sounds of the water).  There is an internal 3-position switch and preset pot which are adjusted  to give the desired sensitivity – once set, you can forget it.<br />
<br />
There are also pots to control clock frequency and tone of alarm – but  these are set in the factory and should not need touching.<br />
<br />
It’s operated by a 9V battery (alkaline preferred) which should last for  at least 12 months. Current drain, when ready to operate but inactive,  is comparable to that of a smoke detector – around 10-15mA.<br />
<br />
The circuit, including the piezo, is housed on a single PC board which  fits (along with the 9V battery) into a purpose-designed two-part case.  When correctly assembled is quite waterproof. Mounted on the shower wall  it allows shower sound to enter and beeps/alarm to escape without the  circuit getting at all damp.<br />
<br />
The case, as we said, is in two parts. These snap together to form a  nice, tight seal around the PC board, with alignment of the two parts  taken care of by pins and holes which mate. Each half of the case is  fitted with a suction cap which allows the unit to mount to any smooth  shower wall (or even a glass screen).<br />
<br />
While the ST4 Shower Timer is available fully built and tested, we are  more interested in it as a kit which you assemble yourself. Even here,  most of the hard work – soldering the surface-mount components and ICs –  is already done for you. In fact, as supplied, the PC board is built  and tested, ready for you to put together <br />
<br />
<span style="font-size: medium;">Putting it together</span><br />
<br />
Assembly is as simple as removing the backing and the centre from the  self-adhesive "donut" foam ring and sticking it, as central as possible,  onto the piezo transducer. Then similarly stick the rectangular foam  pad onto the back of the PC board (it keeps the battery snug while  preventing it shorting to or across the board), then push the PC board  into the bottom half of the case.</div>
<div class="separator" style="clear: both; text-align: center;">
<img alt="4-minute-shower-timer-circuits-diagrams1" border="0" height="270" src="http://1.bp.blogspot.com/-DIlY1e_TstQ/UL9L-8N0mPI/AAAAAAAAHVo/IQo5FE8BTk4/s400/103674_3mg.jpg" title="4-minute-shower-timer-circuits-diagrams1" width="400" /></div>
<div style="text-align: justify;">
<br />
The bottom half can be identified by the slots for the transducer. When  the board is pushed fully home, the foam donut "gasket" provides a seal  in a moulded housing inside the case, preventing any water entering the  case – theoretically even if dunked.<br />
<br />
We say theoretically because it is designed that way – but commonsense  would suggest you don’t try to prove it. Because the transducer slots  are at the bottom of the case, spray would have to be travelling upwards  to enter – possible, of course.<br />
<br />
But the foam donut stops this water going any further. While the  transducer itself is not sealed, its internal construction means that it  is also an effective water barrier, so with the sealing donut in place,  spray cannot enter the case nor either around or through the  transducer.<br />
<br />
All this means that the shower timer is for all intents and purposes  waterproof, especially from spray. Once the PC board has been pushed  home, the battery can be connected and slid down into the case,  alongside the (now insulated) back of the PC board. It should be a  relatively snug fit.<br />
<br />
In the unlikely event that the suction caps have come off the case  halves in transit, simply slide them back into their respective slots on  each end – the photos show where they go. Slide the two halves of the  case together, ensuring that the channels which hold the suction caps  line up exactly – the pins in one half won’t mate if they don’t. The two  case halves should "snap" together and that completes construction.<br />
<br />
<span style="font-size: medium;">Testing</span><br />
<br />
If you don’t want to get wet, you can use a small unmuted FM radio,  off-station, to simulate the sound of a shower. (If your FM radio mutes  automatically, or the mute cannot be turned off, this option won’t work.  You’ll need to check it in situ – in the shower!) The FM radio will  produce predominantly white noise, which is fairly close to the sound of  a shower stream striking the bottom of the shower or bath. <br />
<br />
Turn the radio on and the timer should give a chirping sound after 20-30  seconds (that’s the water temperature adjustment period). Then it  should beep after each minute from there, with a series of beeps (7.5  seconds on, 7.5 seconds off) at the end of four minutes. Turn the radio  off and the timer should reset.<br />
<br />
<span style="font-size: medium;">Mounting in the shower</span><br />
<br />
The timer always mounts vertically, with the piezo transducer towards  the bottom. The suction caps should stick very well to any ceramic tile,  glass or other smooth surface – if necessary, give ’em a lick first!  Best position for the timer is about 300-400mm from the floor but it  should work reasonably well up to about waist height.<br />
<br />
If you need to mount the unit higher than this, or if it doesn’t appear  to be sensitive enough, open it up and slide the switch up one notch.  Don’t mount any higher than necessary. In some very low volume showers,  (eg some gravity feeds), you might need to adjust the sensitivity right  up but this would normally be unlikely.<br />
<br />
You should not need to adjust any of the pots – they are preset on  factory assembly. Once mounted, give it another run, this time with the  shower. It should perform in the same way as it did in your "white  noise" test.<br />
<br />
The only time you should need to remove the unit from the wall is to  replace the battery and this could be up to a couple of years or so!  Don’t pull on the timer to remove it, slide a knife or some other thin,  flat object under the suction caps to break the seal. </div>
<div style="text-align: justify;">
<br />
<div style="text-align: right;">
<br /></div>
<div style="text-align: right;">
<b>Sourced : <a href="http://www.circuitsproject.com/" target="_blank">Circuitsproject</a></b></div>
</div>
</div>

4-Minute Shower Timer

Gone are the days when we can afford to luxuriate under a hot shower for hours on end. Well, maybe the showers weren’t quite that long bu...

Soldering Iron Tip Preserver

Choice and Hobby 04:46

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-7582677031315506166" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-7229344036216391056">
<div align="justify">
Although  60/40 solder melts at about 200&degC, the tip temperature of a  soldering iron should be at about 370&degC. This is necessary to  make a good quick joint, without the risk of overheating delicate  components because the iron has to be kept on the joint for too long.  Unfortunately, at this temperature, the tip oxidises rapidly and needs  constant cleaning. That's where this circuit can help - it keeps the  soldering tip to just below 200&degC while the iron is at rest.  Oxidisation is then negligible and the iron can be brought back up to  soldering temperature in just a few seconds when needed. In addition,  normal soldering operation, where the iron is returned to rest only  momentarily, is unaffected because of the thermal inertia of the iron.  Two 555 timers (IC1 & IC2) form the heart of the circuit. </div>
<div align="justify">
<br /></div>
<b>Circuit diagram:</b><br />
<br />
<span style="color: black;"><a href="http://www.ecircuitslab.com/" target="_blank"><img alt="soldering-iron-tip-preserver circuit diagram" border="0" height="179" src="http://lh5.ggpht.com/-7EO4LpOwuiA/TmkTtRHqH0I/AAAAAAAADn0/578UTDVlpQ4/soldering-iron-tip-preserver%252520circuit%252520diagram%25255B6%25255D.jpg?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="soldering-iron-tip-preserver circuit diagram" width="500" /></a></span><br />
<div align="center">
<b>Soldering Iron Tip Preserver Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
IC1 is wired as a monostable and provides an  initial warm-up time of about 45 seconds to bring the iron up to  temperature. At the end of this period, its pin 3 output switches high  and IC2 (which is wired in astable configuration) switches the iron on -  via relay RLY1 - for about one second in six to maintain the standby  temperature. The presence of the iron in its stand is sensed by  electrical contact between the two and some slight modification of the  stand may be necessary to achieve this. When the iron is at rest, Q1's  base is pulled low and so Q1 is off. Conversely, when the iron is out of  its stand, Q1 turns on and pulls pins 2 & 6 of IC2 high, to inhibit  its operation. During this time, pin 3 of IC2 is low and so the iron is  continuously powered via RLY1's normally closed (NC) contacts. Note  that the particular soldering iron that the circuit was designed for has  its own 24V supply transformer. Other irons may need different power  supply arrangements. The warm-up time and standby temperature can be  varied by altering R2 and R5, as necessary.</div>
<div align="justify">
</div>
<div align="justify">
</div>
<div style="text-align: right;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/soldering-iron-tip-preserver.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

Soldering Iron Tip Preserver

Although 60/40 solder melts at about 200&degC, the tip temperature of a soldering iron should be at about 370&degC. This ...

Remote Control Receiver

Choice and Hobby, Controller 05:41

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
Hello! in this post I will show a remote control receiver, I tested this circuit with an approximate distance of 4 meters and it worked perfectly, the spread of this circuit is that it can be triggered by remote control of multiple devices, I tested with two remote controls one tV receiver and a satellite dish, every time you press a key on the remote, the LED will light up and trigger the relay, the relay output you can connect any device you want to control the 1N4148 diode D4 is also You can add more channels to the circuit, just by connecting the reset of the integrated circuit in 4017 and adding another exit other relés.Assim each pulse sent to the receiver, trigger a relay!<br />
<br />
The relay coil has voltage according to the circuit power!<br />
<br />
<b>See the figure below:</b></div>
<div style="text-align: justify;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieJJUze0EjNXPY71x8dnn9hZTrRPs4rm7Rp6R6lhJhPjVOa0IcEtbrQbwlqyKo9toil8qTJE64L1T6mtFRh04TDOlLCHZmshSsolHkoY_qmLtpUKdflXlu9Lw5VA_gM8zDTHokdyriCXFi/s1600/Remot+control+reciever.GIF" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieJJUze0EjNXPY71x8dnn9hZTrRPs4rm7Rp6R6lhJhPjVOa0IcEtbrQbwlqyKo9toil8qTJE64L1T6mtFRh04TDOlLCHZmshSsolHkoY_qmLtpUKdflXlu9Lw5VA_gM8zDTHokdyriCXFi/s400/Remot+control+reciever.GIF" width="392" /></a></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The receiver used is three terminals, commonly used in television sets!</div>
<div style="text-align: justify;">
<br />
<b>See the figure below:</b></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRXUP3Dut49kPqixar7Hifp5CM1Jxbgc6KUnsgLiX6c9MjsRObZQWE_z_16FuQMg0xNng5KBayE30KC0hWs-n1CV-IM0iUIFrcgiMBFVJvZwOnsQCeIvCVZzmMC9oE_AFPUb4vZWQfycjX/s1600/Sensor1.GIF" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="303" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRXUP3Dut49kPqixar7Hifp5CM1Jxbgc6KUnsgLiX6c9MjsRObZQWE_z_16FuQMg0xNng5KBayE30KC0hWs-n1CV-IM0iUIFrcgiMBFVJvZwOnsQCeIvCVZzmMC9oE_AFPUb4vZWQfycjX/s320/Sensor1.GIF" width="320" /></a></div>
<div style="text-align: right;">
<br />
<br />
Sourced By: <b>Circuitsproject</b></div>
</div>

Remote Control Receiver

Hello! in this post I will show a remote control receiver, I tested this circuit with an approximate distance of 4 meters and it worked pe...

Going for Gold

Choice and Hobby 11:53

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4108506393854237276" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-7534570272222053085">
<div align="justify">
The  title refers to a popular TV game show where the contestants each have a  big button.  The  game show  host  asks  a  question and the first  contestant to press their but-ton makes an illuminated indicator light  up on their desk. The other contestants’ buttons  are automatically  inhibited, so that everyone can see who was the first contestant to  press their button, and so is allowed to answer the question. The  project described here shows how to build a similar sortof  refereeing  device yourself, using simple resources and without needing a  microcontroller, which is  pretty rare these days! The basic circuit is  for  just two contestants, but the modular design  means it can easily  be expanded. </div>
<div align="justify">
<br /></div>
<div align="justify">
<b>Circuit diagram :</b> </div>
<div align="justify">
 <span style="color: black;"><a href="http://lh3.ggpht.com/-KF1tn6mzqYI/T2ov__t5ZQI/AAAAAAAAE2w/WQ5fO9n7Y88/s1600-h/Going%252520for%252520Gold-Circuit-Diagram%25255B7%25255D.png" target="_blank"><img alt="Going for Gold-Circuit-Diagram" border="0" height="320" src="http://lh6.ggpht.com/-_i9ldoonlmA/T2owB18MZlI/AAAAAAAAE24/O6vaYTkyEJs/Going%252520for%252520Gold-Circuit-Diagram_thumb%25255B5%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Going for Gold-Circuit-Diagram" width="500" /></a></span> </div>
<div align="center">
<b>Going for Gold Circuit Diagram </b></div>
<div align="justify">
<br /></div>
<div align="justify">
The diagram shows three buttons: S2 and S3   are the buttons for the two contestants, S1 is  the button for the host,  which allows them to  reset the circuit before each fresh question.   The ‘brains’ of the circuit is IC1, a 4013 dual D-type flip-flop, of  which only the Set and Reset  inputs are used here. This circuit can  handle  quite a wide supply voltage range, from 3 to  15 V, and so the  project can easily be run off a 4.5 V battery pack (the power  consumption is minimal). </div>
<div align="justify">
<br /></div>
<div align="justify">
IC1 is armed by pressing S1 (reset). In this   state, the non-inverting outputs (pins 1 and  13) are at 0 and the  inverting outputs (pins 12  and 12) are at 1. Hence line A is pulled  high  by R1, since diodes D2 and D4 are not biased  on. If contestant 1  presses button S2, the  non-inverting output of flip-flop IC1a goes  to  logic 1, and LED D1 lights via T1 to indicate that contestant 1 has  pressed the but-ton. At the same time, the flip-flop’s invert-ing output  goes to logic 0, making diode  D2 conduct. Line A is now pulled down to  0,  and consequently contestant 2’s button S3  can no longer trigger  the second flip-flop.  The reverse happens if it is contestant 2 who   presses their button S3 first. </div>
<div align="justify">
<br /></div>
<div align="justify">
The circuit can be extended to 4 or 6  contest-ants (or even more) by adding a second or  third (or more) 4013  IC. All you have to do is  repeat the circuit (minus R1, R2, and S1) and  connect to the A, B, Vdd, and 0 V lines on the right-hand side. </div>
<div style="text-align: right;">
<br />
<br />
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/going-for-gold.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

Going for Gold

The title refers to a popular TV game show where the contestants each have a big button. The game show host asks a question...

UV Torch Light

Choice and Hobby 13:15

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-5616281695660836414" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-1008912799512890346">
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
UV  (ultra-violet) LEDs can produce eye-catching effects when their light  is allowed to interfere with certain colours, particularly with  reflected light under near-dark conditions. Also try shining some UV  light on a diamond.</div>
<div style="text-align: justify;">
<br /></div>
<b>Circuit diagram :</b><br />
<b><a href="http://lh5.ggpht.com/-EfGnhsHlwoo/T7vgnaHE8MI/AAAAAAAAFpo/EBWuvHfWMjY/s1600-h/UV%252520Torch%252520Light-Circuit%252520Diagram%25255B6%25255D.png"><img alt="UV Torch Light-Circuit Diagram" border="0" height="281" src="http://lh6.ggpht.com/-NnAXkHDAx58/T7vgox0nYbI/AAAAAAAAFpw/jtm_oHtxn7w/UV%252520Torch%252520Light-Circuit%252520Diagram_thumb%25255B4%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="UV Torch Light-Circuit Diagram" width="450" /></a> </b><br />
<div align="center">
<b> UV Torch Light Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div style="text-align: justify;">
Most UV LEDs require about 3.6 V  (the ‘blue’ diode voltage) to light. Here, a MAX761 step-up switching  IC is used to provide constant current to bias the UV diode. The IC  employs PWM in high-cur-rent mode and automatically changes to PFM mode  in low or medium power mode to save (battery) power. To allow it to be  used with two AA cells, the MAX761 is configured in bootstrapped mode  with voltage-adjustable feedback. Up to four cells may be used to power  the circuit but they may add more weight than you would like for a  torchlight. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
To prolong the  switch life, R1 is connected to the IC’s SHDN (shutdown) pin. Less than  50 nA will be measured in shutdown mode. Electrolytic capacitor C1 is  used to decouple the circuit supply voltage. With-out it, ripple and  noise may cause instability. The one inductor in the circuit, L1, may  have any value between about 10 and 50 µH. It stores current in its  magnetic field while the MOSFET inside the MAX761 is switched. A toroid  inductor is preferred in this position as it will guarantee low stray  radiation. D1 has to be a relatively fast diode so don’t be tempted to  use an 1N400x because it has a too slow recovery time. </div>
<div style="text-align: justify;">
The  circuit efficiency was measured at about 70%. R2, the resistor on the  feed-back pin of the MAX761 effectively determines the amount of  constant current, I, sent through the UV LEDs, as follows: R2 = 1.5 / I </div>
<div style="text-align: justify;">
where I will be between 2 mA and 35 mA. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Zener  diode D4 clamps the output voltage when the load is disconnected, which  may happen when one of the UV LEDs breaks down. Without a load, the  MAX761 will switch L1 right up to the boost voltage and so destroy  itself.</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: right;">
</div>
<div style="text-align: right;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/uv-torch-light.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

UV Torch Light

UV (ultra-violet) LEDs can produce eye-catching effects when their light is allowed to interfere with certain colours, particul...

Long-Delay Stop Switch

Choice and Hobby 05:45

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-3229495078922325389" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-8703849010728929559">
<div align="justify">
Presettable  times for train stops in stations are indispensable if you want to  operate your model railway more or less realistically according to a  timetable. This circuit shows how a 555 timer can be used with a  relatively small timing capacitor to generate very long delay times as  necessary by using a little trick (scarcely known among model railway  electronic technicians): pulsed charging of the timing net-work. Such  long delays can be used in hidden yards with through tracks, for  instance.  As the timer is designed for half-wave operation, it requires  only a single lead to the transformer and one to the switching track or  reed contact when used with a Märklin AC system (H0 or H1). The other  lead can be connected to any desired grounding point for the common  ground of the track and lighting circuits.<br />
<br /></div>
<div align="justify">
<b>Circuit diagram :</b></div>
<div align="justify">
<b><a href="http://lh5.ggpht.com/-7_ScBTlL1C8/T6wW4svO6FI/AAAAAAAAFds/2lhDp-fsirA/s1600-h/Long-Delay%252520Stop%252520Switch-Circuit%252520Diagram%25255B7%25255D.png" target="_blank"><img alt="Long-Delay Stop Switch-Circuit Diagram" border="0" height="298" src="http://lh5.ggpht.com/-sRXIJNzS_hM/T6wW6q_es3I/AAAAAAAAFd0/voXOsoNDuOQ/Long-Delay%252520Stop%252520Switch-Circuit%252520Diagram_thumb%25255B5%25255D.png?imgmax=800" style="border-width: 0px; display: block; float: none; margin-left: auto; margin-right: auto;" title="Long-Delay Stop Switch-Circuit Diagram" width="450" /></a> </b></div>
<div align="center">
<b>Long-Delay Stop Switch Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
As seen from the outside, the timer acts as a  monostable flip-flop. The output (pin 3) is low in the quiescent state.  If a negative signal is applied to the trigger input (pin 2), the  output goes high and C4 starts charging via R3 and R4. When the voltage  on C4 reaches 2/3 of the supply voltage, it discharges via an internal  transistor connected to pin 7 to 1/3 of the supply voltage and the  output (pin 3) goes low. The two threshold values (1/3 and 2/3) are  directly proportional to the supply voltage. The duration of the output  signal is independent of the supply voltage: t= 1.1(R4 + R5) × C4 </div>
<div align="justify">
<br /></div>
<div align="justify">
if the potentiometer is connected directly to  the supply line (A and B joined). The maximum delay time that can be  generated using the component values shown in the schematic diagram is  4.8 minutes. How-ever, it can be increased by a factor of approximately  10 if the timing network is charged using positive half-waves of the AC  supply voltage (reduced to the 10–16-V level) instead of a constant DC  voltage. </div>
<div align="justify">
<br /></div>
<div align="justify">
The positive half-waves of the AC voltage  reach the timing network via D2, the transistor, and D3. Diode D3  prevents C4 from being discharged between the pulses. The total  resistance of R4 and R5 should not be too high (no more than 10 MΩ if  possible), since electrolytic capacitors (such as are needed for C4)  have significant leakage currents. Incidentally, the leakage current of  aluminium electrolytic capacitors can be consider-ably reduced by using a  supply voltage well below the rated voltage. Capacitor C6 is intended  to suppress noise. It forms a filter network in combination with an  internal voltage-divider resistor.<br />
<br />
</div>
<div align="justify">
If a  vehicle happens to remain standing over the reed switch so the magnet  holds the contacts constantly closed, the timer will automatically be  retriggered when the preset delay times out. In this case the relay  armature will not release and the locomotive will come to the ‘end of  the line’ in violation of the timetable. This problem can be reliably  eliminated using R6, R7 and C5. This trigger circuit ensures that only  one trigger pulse is generated, regardless of how long the reed switch  remains closed. RC network R8/C7 on the reset pin ensures that the timer  behaves properly on switch-on (which is far from being something to be  taken for granted with many versions of the 555 or 556 dual timer).<br />
<br />
</div>
<div align="justify">
Reed  switches have several special characteristics that must be kept in mind  when fitting them. The contact blades, which are made from a  ferromagnetic material, assume opposite magnetic polarities under the  influence of a magnetic field and attract each other. Here the position  and orientation of the magnet, the distance between the magnet and the  reed switch, and the direction of motion of the magnet relative to the  switch are important factors. The fragility of the glass hous-ing and  the thermal stress from soldering (stay at least 3 mm away from the  glass housing) require a heat sink to be used between the soldering  point and the glass/metal seal. A suitable tweezers or flat-jawed pliers  can be used for this pur-pose. If you need to bend the leads, use  flat-jawed pliers to protect the glass/metal seal against mechanical  stresses. </div>
<div align="justify">
<br /></div>
<div align="justify">
Matching magnets in various sizes are  available from toy merchants and electronics mail-order firms. They  should preferably be fitted underneath the loco-motive or carriage.  However, the magnet can also be fitted on the side of a vehicle with a  plastic body. In this case the reed switch can be hidden in a mast,  bridge column or similar structure or placed in a tunnel, since the  distance must be kept to less than around 10 mm, even with a strong  magnet. If fitting the circuit still presents problems (especially with  Märklin Z-gauge Mini-Club), one remedy is to generate the trigger using a  unipolar digital Hall switch, such as the Siemens TLE4905L or Allegro  UGN3120. To avoid coupled-in interference, the stop timer should be  fitted relatively close to the Hall sensor (use screened cable if  necessary). Pay attention to the polarity of the magnet when fitting it  to the bottom of the vehicle. With both types of sensors, the South pole  must point toward the front face of the Hall IC (the face with the type  marking). The North pole is sometimes marked by a dab of paint.  Generally speaking, the polarity must be determined experimentally. </div>
<div align="justify">
<br /></div>
<div align="justify">
Fitting the circuit is not a problem with  Z-gauge and 1-gauge tracks, since the distance between the iron parts  (rails) and the Hall switch is sufficiently large. In an HO system, some  modifications must be made to the track bed of the Märklin metal track.  Cut a suitably sized ‘window’ between one wheel rail and the centre  rail in order to prevent secondary magnetic circuits from interfering  with the operation of the sensor. Keep the distance between the magnet  and the case of the Hall switch between 5 and 10 mm, depending on the  strength of the magnet, to ensure reliable actuation.</div>
<div align="justify">
<br /></div>
<div align="justify">
<br /></div>
<div style="text-align: right;">
<br /></div>
<div style="text-align: right;">
<b><br /></b></div>
<div style="text-align: right;">
<b>Source by : <span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/long-delay-stop-switch.html" target="_blank">Streampowers</a></span></b></div>
</div>
</div>
</div>
</div>
</div>

Long-Delay Stop Switch

Presettable times for train stops in stations are indispensable if you want to operate your model railway more or less realistic...

RGB Solar Lamp

Choice and Hobby 12:08

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-9135298676117314501" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div align="justify">
This  deluxe solar-powered light  uses a battery and solar cells salvaged  from a solar lamp with a four-cell battery (4.8 V nominal terminal   voltage).<br />
<br /></div>
<div align="justify">
<b>Circuit diagram :</b></div>
<div align="justify">
<span style="color: black;"><a href="http://lh5.ggpht.com/-uo2yc4V6LUQ/T6bIwFeGOwI/AAAAAAAAFYs/Aa5E2C4EKhM/s1600-h/RGB%252520Solar%252520Lamp-Circuit%252520Diagram%25255B7%25255D.png" target="_blank"><img alt="RGB Solar Lamp-Circuit Diagram" border="0" height="355" src="http://lh4.ggpht.com/-Hgce8TOB5zc/T6bIxsgz4cI/AAAAAAAAFY0/98gaNCuEjnk/RGB%252520Solar%252520Lamp-Circuit%252520Diagram_thumb%25255B5%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="RGB Solar Lamp-Circuit Diagram" width="450" /></a></span> </div>
<div align="center">
<b>RGB Solar Lamp Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
The circuit can operate from any  DC voltage  around this value and  its current consumption, at 20 mA,  is low. This  means that the battery  can give up to ﬁve days of operation. The  circuit consists of an Atmel  ATtiny microcontroller which drives  a  red, a green and a blue LED directly  from three port pins. Series  resistors are of course included to limit  the LED current. The  microcontroller  drives the LEDs in sequence to produce an  RGB running  light effect. The microcontroller  is also responsible for ensuring that  the light automatically switches on when it gets dark  and off when it  is light. The light sensor is  made from one of the solar cells from a  bro-ken solar lamp (it is more common  for the battery to fail rather  than  the solar cells). </div>
<div align="justify">
<br /></div>
<div align="justify">
The power output of this cell is not   important, as the microcontroller  only measures its output voltage   using its internal A/D converter  connected to pin PB4. The project is   ideal for beginners, as a ready-programmed microcontroller is avail-able  from the Elektor Shop (order  code 100581-41). </div>
<div align="justify">
<br /></div>
<div align="justify">
<br /></div>
<div align="justify">
<br /></div>
<div align="justify">
<b>Source by : <a href="http://streampowers.blogspot.com/2012/07/rgb-solar-lamp.html" target="_blank">Streampowers</a></b></div>
</div>
</div>
</div>

RGB Solar Lamp

This deluxe solar-powered light uses a battery and solar cells salvaged from a solar lamp with a four-cell battery (4.8 V nominal t...

Model Railway Short-Circuit Beeper

Choice and Hobby 01:10

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-5166206817208809612" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div align="justify">
Short  circuits in the tracks, points or wiring are almost inevitable when  building or operating a model railway. Although transformers for model  systems must be protected against short circuits by built-in bimetallic  switches, the response time of such switches is so long that is not  possible to immediately localise a short that occurs while the trains  are running, for example. Furthermore, bimetallic protection switches do  not always work properly when the voltage applied to the track circuit  is relatively low. </div>
<div align="justify">
<br /></div>
<div align="justify">
<b>Circuit diagram :</b></div>
<div align="justify">
<b><a href="http://lh4.ggpht.com/-DpKcLdOblyE/T5w7-nZ59WI/AAAAAAAAFQI/aZ6L7TNhVSk/s1600-h/Model%252520Railway%252520Short-Circuit%252520Beeper-Circuit%252520Diagram%25255B7%25255D.png" target="_blank"><img alt="Model Railway Short-Circuit Beeper-Circuit Diagram" border="0" height="345" src="http://lh4.ggpht.com/-iL5I1OCvn2s/T5w8LEkjqSI/AAAAAAAAFQQ/-2MaKtewwoQ/Model%252520Railway%252520Short-Circuit%252520Beeper-Circuit%252520Diagram_thumb%25255B5%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Model Railway Short-Circuit Beeper-Circuit Diagram" width="450" /></a> </b></div>
<div style="text-align: center;">
<b>Model Railway Short-Circuit Beeper Circuit Diagram</b></div>
<div align="justify">
<br /></div>
<div align="justify">
The rapid-acting acoustic short-circuit  detector described here eliminates these problems. However, it requires  its own power source, which is implemented here in the form of a GoldCap  storage capacitor with a capacity of 0.1 to 1 F. A commonly available  reed switch (filled with an inert gas) is used for the current sensor,  but in this case it is actuated by a solenoid instead of a permanent  magnet. An adequate coil is provided by several turns of 0.8–1 mm  enamelled copper wire wound around a drill bit or yarn spool and then  slipped over the glass tube of the reed switch. This technique generates  only a negligible voltage drop. The actuation sensitivity of the switch  (expressed in ampèreturns or A-t)) deter-mines the number of turns  required for the coil. For instance, if you select a type rated at 20–40  A-t and assume a maxi-mum allowable operating current of 6 A, seven  turns (40 ÷ 6 = 6.67) will be sufficient. As a rule, the optimum number  of windings must be determined empirically, due to a lack of  specification data. </div>
<div align="justify">
<br /></div>
<div align="justify">
As you can see from the circuit diagram, the  short-circuit detector is equally suitable for AC and DC railways. With  Märklin transformers (HO and I), the track and lighting circuits can be  sensed together, since both circuits are powered from a single secondary  winding. </div>
<div align="justify">
<br /></div>
<div align="justify">
Coil L1 is located in the common ground lead  (‘O’ terminal), so the piezoelectric buzzer will sound if a short  circuit is present in either of the two circuits. The (positive) trigger  voltage is taken from the lighting circuit (L) via D1 and series  resistor R1. Even though the current flowing through winding L1 is an AC  or pulsating DC current, which causes the contact reeds to vibrate in  synchronisation with the mains frequency, the buzzer will be activated  because a brief positive pulse is all that is required to trigger  thyristor Th1. The thyristor takes its anode voltage from the GoldCap  storage capacitor (C2), which is charged via C2 and R2.  The alarm can  be manually switched off using switch S1, since although the thyris-tor  will return to the blocking state after C2 has been discharged if a  short circuit is present the lighting circuit, this will not happen if  there is a short circuit in the track circuit. C1 eliminates any noise  pulses that may be generated. </div>
<div align="justify">
<br /></div>
<div align="justify">
As a continuous tone does not attract as much  attention as an intermittent beep, an intermittent piezoelectric  generator is preferable. As almost no current flows during the intervals  between beeps and the hold current through the thyristor must be kept  above 3 mA, a resistor with a value of 1.5–1.8 kΩ is connected in  parallel with the buzzer. This may also be necessary with certain types  of continuous-tone buzzers if the operating current is less than 3 mA.  The Zener diode must limit the operating voltage to 5.1 V, since the  rated volt-age of the GoldCap capacitor is 5.5 V.</div>
<div align="justify">
</div>
<div align="justify">
</div>
<div align="justify">
</div>
<div align="justify">
source by : <span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/model-railway-short-circuit-beeper.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>

Model Railway Short-Circuit Beeper

Short circuits in the tracks, points or wiring are almost inevitable when building or operating a model railway. Although transforme...

Wire Loop Game

Choice and Hobby 12:01

Wire Loop Game

In the ‘Wire Loop Game’, a test of dexterity, the player has to pass a metal hoop along a twisted piece of wire without lett...

Portable Muscular Bio-Stimulator

Choice and Hobby 22:17

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
This  is a small, portable set, designed for those aiming at look  improvement. The Bio-Stimulator provides muscles' stimulation and  invigoration but, mainly, it could be an aid in removing cellulite. Tape  the electrodes to the skin at both ends of the chosen muscle and rotate  P1 knob slowly until a light itch sensation is perceived. Each session  should last about 30 - 40 minutes.<br />
<div style="text-align: justify;">
<br /></div>
<b>Circuit diagram :</b><br />
<b><img alt="Portable Muscular Bio-Stimulator-Circuit Diagram" border="0" height="312" src="http://lh6.ggpht.com/-6gtb4VK1YZI/T706TrOGB4I/AAAAAAAAFqg/SKreLOEcO9k/Portable%252520Muscular%252520Bio-Stimulator-Circuit%252520Diagram%25255B6%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Portable Muscular Bio-Stimulator-Circuit Diagram" width="472" /> </b><br />
<div align="center">
<b>Portable Muscular Bio-Stimulator Circuit Diagram</b></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
C1 generates  150µSec. pulses at about 80Hz frequency. Q1 acts as a buffer and Q2  inverts the polarity of the pulses and drives the Transformer. The  amplitude of the output pulses is set by P1 and approximately displayed  by the brightness of LED D1. D2 protects Q2 against high voltage peaks  generated by T1 inductance during switching.<br />
<br />
</div>
<div style="text-align: justify;">
<b>Parts :</b></div>
<ul style="text-align: justify;">
<li>P1-----4K7 Linear Potentiometer</li>
<li>R1-----180K   1/4W Resistor</li>
<li>R2-----1K8  1/4W Resistor (see Notes)</li>
<li>R3-----2K2  1/4W Resistor</li>
<li>R4-----100R   1/4W Resistor</li>
<li>C1-----100nF  63V Polyester Capacitor</li>
<li>C2-----100µF  25V Electrolytic Capacitor</li>
<li>D1-----LED  Red 5mm.</li>
<li>D2-----1N4007  1000V 1A Diode</li>
<li>Q1,Q2-----BC327  45V 800mA PNP Transistors</li>
<li>IC1-----7555 or TS555CN CMos Timer IC</li>
<li>T1-----220V Primary, 12V Secondary 1.2VA Mains transformer (see Notes)</li>
<li>SW1-----SPST Switch (Ganged with P1)</li>
<li>B1-----3V Battery (two 1.5V AA or AAA cells in series etc.)</li>
</ul>
<div style="text-align: justify;">
<b>Notes :</b></div>
<ul style="text-align: justify;">
<li>T1  is a small mains transformer 220 to 12V @ 100 or 150mA. It must be  reverse connected i.e. the 12V secondary winding across Q2 Collector and  negative ground, and the 220V primary winding to output electrodes.</li>
<li>Output voltage is about 60V positive and 150V negative but output current is so small that there is no electric-shock danger.</li>
<li>In any case P1 should be operated by the "patient", starting with  the knob fully counter-clockwise, then rotating it slowly clockwise  until the LED starts to illuminate. Stop rotating the knob when a light  itch sensation is perceived. <br />Best knob position is usually near the center of its range. </li>
<li>In some cases a greater pulse duration can be more effective in  cellulite treatment. Try changing R2 to 5K6 or 10K maximum: stronger  pulses will be easily perceived and the LED will shine more brightly. </li>
<li>Electrodes can be obtained by small metal plates connected to the  output of the circuit via usual electric wire and can be taped to the  skin. In some cases, moistening them with little water has proven  useful. </li>
<li>SW1 should be ganged to P1 to avoid abrupt voltage peaks on the  "patient's" body at switch-on, but a stand alone SPST switch will work  quite well, provided you remember to set P1 knob fully counter-clockwise  at switch-on. </li>
<li>Current drawing of this circuit is about 1mA @ 3V DC. </li>
<li>Some commercial sets have four, six or eight output electrodes. To  obtain this you can retain the part of the circuit comprising IC1, R1,  R2, C1, C2, SW1 and B1. Other parts in the diagram (i.e. P1, R3, R4, D1,  D2, Q2 & T1) can be doubled, trebled or quadrupled. Added  potentiometers and R3 series resistors must be wired in parallel and all  connected across Emitter of Q1 and positive supply. </li>
<li>Commercial sets have frequently a built-in 30 minutes timer. For  this purpose you can use the Timed Beeper the Bedside Lamp Timer or the  Jogging Timer circuits available on this Website, adjusting the timing  components to suit your needs. </li>
</ul>
<div style="text-align: justify;">
<b>Disclaimer:</b> we can't claim or prove any therapeutic effectiveness for this device.</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/portable-muscular-bio-stimulator.html" target="_blank">Streampowers </a></span></div>
</div>
</div>

Portable Muscular Bio-Stimulator

This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and ...

Whistling Kettle

Choice and Hobby 22:16

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4819273331882236364" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4233967713969846624">
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
Most  electric kettles do not produce a whistle and just switch off when they  have boiled. Fitting a box of electronics directly onto an electric  kettle (or even inside!) to detect when the kettle has boiled is  obviously out of the question. The circuit shown here detects when the  kettle switches off, which virtually all kettles do when the water has  boiled. In this way, the electronics can be housed in a separate box so  that no modification is required to the kettle. The box is prefer-ably a  type incorporating a mains plug and socket. </div>
<br />
<span style="color: black;"><img alt="Cap" border="0" height="170" src="http://lh4.ggpht.com/-ms4vRJTYKh8/T8PblFMQYTI/AAAAAAAAF6s/FdJLDi8clMA/Cap%25255B8%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Cap" width="300" /></span> <br />
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
In this application, the current  flowing in coil L1 provides a magnetic field that actuates reed switch  S1. Since the current drawn by the kettle element is relatively large  (typically 6 to 8 amps), the coil may consist of a few turns of wire  around the reed switch. The reed switch is so fast it will actually  follow the AC current flow through L1 and produce a 100-Hz buzz. The  switching circuit driven by the reed switch must, therefore, disregard  these short periods when the contacts open, and respond only when they  remain open for a relatively long period when the kettle has switched  off. </div>
<div style="text-align: justify;">
<br /></div>
<b>Circuit diagram :</b><br />
<span style="color: black;"><a href="http://lh4.ggpht.com/-VxFnb635SiY/T8Pbp_g1ZtI/AAAAAAAAF60/2ZaaE0PxmGY/s1600-h/Whistling%252520Kettle%252520Circuit%252520d%25255B7%25255D.png" target="_blank"><img alt="Whistling Kettle Circuit d" border="0" height="317" src="http://lh5.ggpht.com/-hyZGIKjXNoU/T8PbuNAxCvI/AAAAAAAAF68/-PlxbO2OAf8/Whistling%252520Kettle%252520Circuit%252520d_thumb%25255B5%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Whistling Kettle Circuit d" width="450" /></a></span> <br />
<div align="center">
<b>Whistling Kettle Circuit Diagram</b></div>
<div style="text-align: justify;">
  </div>
<div style="text-align: justify;">
The  circuit is based on a simple voltage controlled oscillator formed  around T2 and T3. Its operation is best understood by considering the  circuit with junction R4/R5 at 0 V and C4 discharged. T2 will receive  base current through R5 and turn on, causing T3 to turn on as well. The  falling collector voltage of T3 is transmitted to the base of T2 by C4  causing this transistor to conduct harder. Since the action is  regenerative, both transistors will turn on quickly and con-duct  heavily. C4 will therefore charge quickly through T2’s base-emitter  junction and T3. Once the voltage across C4 exceeds about 8.5 V (leaving  less than 0.5 V across T2’s b-e junction), T2 will begin to turn off.  This action is also regenerative so that soon both transistors are  switched off and the collector volt-age of T3 rises rapidly to +9 V.  With C4 still charged to 8.5 V, the base of T2 will rise to about 17.5 V  holding T2 (and thus T3) off. C4 will now discharge relatively slowly  via R5 until T2 again begins to conduct whereupon the cycle will repeat.  The voltage at the collector of T3 will therefore be a series of short  negative going pulses whose basic frequency will depend on the value of  C4 and R5. The pulses will be reproduced in the piezo sounder as a  tone. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The  oscillation frequency of the regenerative circuit is heavily dependent  on the voltage at junction R4/R5. As this voltage increases, the  frequency will fall until a point is reached when the oscillation stops  altogether. With this in mind, the operation of the circuit around T1  can be considered. In the standby condition, when the kettle is off, S1  will be open so that C1 and C2 will be discharged and T1 will remain off  so that the circuit will draw no current. When the kettle is switched  on, S1 is closed, causing C1 and C2 to be discharged and T1 will remain  off. C3 will remain discharged so that T2 and T3 will be off and only a  small current will be drawn by R1. Although S1 will open periodically  (at 100 Hz), the time constant of R1/C1 is such that C1 will have  essentially no voltage on it as the S1 contacts continue to close. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
When  the kettle switches off, S1 will be permanently open and C1/C2 will  begin to charge via R1, causing T1 to switch on. C3 will then begin to  charge via R4 and the falling voltage at junction R4/R5 will cause T2/T3  to start oscillating with a rising frequency. However, once T1 has  switched off, C3 will no longer be charged via R4 and will begin to  discharge via R3 and R5 causing the voltage at R4/R5 to rise again. The  result is a falling frequency until the oscillator switches off,  returning the circuit to its original condition. As well as reducing the  current drawn by the circuit to zero, this mimics the action of a  conventional whistling kettle, where the frequency rises as more steam  is produced and then falls when it is taken off the boil. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The  circuit is powered directly by the mains using a ‘lossless’ capacitive  mains dropper, C6, and zener a diode, D2, to provide a nominal 8 V dc  supply for the circuit.  A 1-inch reed switch used in the prototype  required about 9 turns of wire to operate with a 2-kW kettle element.  Larger switches or lower current may require more turns. In general, the  more turns you can fit on the reed switch, the better, but do remember  that the wire has to be thick enough to carry the current. It is  strongly recommended to test the circuit using a 9-volt battery instead  of the mains-derived supply voltage shown in the circuit diagram. A  magnet may be used to operate S1 and so simulate the switching of the  kettle. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<span style="font-size: small;"><b>Warning.</b></span>  This circuit is connected directly to the 230-V mains and none of the  components must be touched when the circuit is in use. The circuit must  be housed in an approved ABS case and carry the earth connection to the  load as indicated. Connections and solder joints to components with a  voltage greater than 200 volts across them (ac or dc) must have an  insulating clearance of least 6 mm. An X2 class capacitor <b>must</b> be used in position C6.</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/whistling-kettle.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

Whistling Kettle

Most electric kettles do not produce a whistle and just switch off when they have boiled. Fitting a box of electronics directly...

Simple Steam Whistle

Choice and Hobby 03:15

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-5643289779301344733" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-2797017602485450004">
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
This  circuit consists of six square wave oscillators. Square waves are made  up of a large number of harmonics. If six square waves with different  frequencies are added together, the result will be a signal with a very  large number of frequencies. When you listen to the result you’ll find  that it is very similar to a steam whistle. The circuit should be useful  in modelling or even in a sound studio.<br />
<br /></div>
Circuit diagram :<br />
<a href="http://lh6.ggpht.com/-ZIDMdOjhO20/T8fcOQLx76I/AAAAAAAAGA0/0hl34-tp2ko/s1600-h/Simple%252520Steam%252520Whistle-Circuit%252520Diagram%25255B7%25255D.png" target="_blank"><img alt="Simple Steam Whistle-Circuit Diagram" border="0" height="558" src="http://lh6.ggpht.com/-WIlVdPjd3To/T8fcQ2_L0iI/AAAAAAAAGA8/oacU37o1mGU/Simple%252520Steam%252520Whistle-Circuit%252520Diagram_thumb%25255B5%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Simple Steam Whistle-Circuit Diagram" width="450" /></a> <br />
<div align="center">
<b>Simple Steam Whistle Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div style="text-align: justify;">
This circuit uses only two ICs.  The first IC, a 40106, contains six Schmitt triggers, which are all  configured as oscillators. Different frequencies are generated by the  use of different feedback resistors. The output signals from the Schmitt  triggers are mixed via resistors. The resulting signal is amplified by  IC2, an LM386. This IC can deliver about 1 W of audio power, which  should be sufficient for most applications. If you leave out R13 and all  components after P1, the output can then be connected to a more  powerful amplifier. In this way a truly deafening steam whistle can be  created. The ‘frequency’ of the signal can be adjusted with P2, and P1  controls the volume.<br />
<br />
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/simple-steam-whistle.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

Simple Steam Whistle

This circuit consists of six square wave oscillators. Square waves are made up of a large number of harmonics. If six square wa...

Soldering Iron Tip Preserver

Choice and Hobby 03:14

Soldering Iron Tip Preserver

Although 60/40 solder melts at about 200&degC, the tip temperature of a soldering iron should be at about 370&degC. This...

Acoustic Distress Beacon

Choice and Hobby 02:55

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<div class="post-header">
</div>
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-855527297045882579">
<div align="justify">
An  ELT (Emergency Locator Transmitter, also known as a distress beacon) is  an emergency radio transmitter that is activated either manually or  automatically by a crash sensor to aid the detection and location of  aircraft in distress. This acoustic ELT project is intended for radio  control (RC) model aircraft, which every now and then decide to go their  own way and disappear into the undergrowth.<br />
<br /></div>
<div align="justify">
</div>
<div align="justify">
<b>Circuit diagram :</b> </div>
<div align="justify">
<span style="color: black;"><a href="http://lh5.ggpht.com/-PzSau_os0B4/T29m7h2nPrI/AAAAAAAAE38/5OV4dKjrbQg/s1600-h/Acoustic%252520Distress%252520Beacon-Circuit%252520Diagram%25255B6%25255D.png"><img alt="Acoustic Distress Beacon-Circuit Diagram" border="0" height="259" src="http://lh4.ggpht.com/-86DrR2kI9P4/T29m9AGYdhI/AAAAAAAAE4E/dZYLHyARCbM/Acoustic%252520Distress%252520Beacon-Circuit%252520Diagram_thumb%25255B4%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Acoustic Distress Beacon-Circuit Diagram" width="450" /></a></span> </div>
<div align="center">
<b>Acoustic Distress Beacon Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
The audio locating device described here  enables model aircraft that have landed ‘off limits’ to be found again  and employs its own independent power supply. The small cam-era battery  shown in the circuit activates an acoustic sounder when radio contact is  lost and produces a short signal tone (bleep) every ten seconds for  more than 25 hours. Current consumption in standby and passive (with  jumper J1 set) modes is negligible. The timing generator for the alarm  tone is the Schmitt trigger AND-gate IC1.B; its asymmetric duty cycle  drives a 5 V DC sounder via MOSFET transistor T1. All the time that the  RC receiver output is delivering positive pulses, the oscillator is  blocked by IC1.A and diode D1. Setting jumper J1 parallel to C2 also  disables the oscillator and serves to ‘disarm’ the distress beacon. </div>
<div align="justify">
<br /></div>
<div align="justify">
<br /></div>
<div style="text-align: right;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/acoustic-distress-beacon.html" target="_blank">Streampowers</a></span></div>
</div>
</div>
</div>
</div>

Acoustic Distress Beacon

An ELT (Emergency Locator Transmitter, also known as a distress beacon) is an emergency radio transmitter that is activated eithe...

Wire Loop Game

Choice and Hobby 03:53

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-1497048847783787999" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-7422038636980188960">
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
In  the ‘Wire Loop Game’, a test of dexterity,  the player has to pass a  metal hoop along a  twisted piece of wire without letting the hoop   touch the wire. Usually all the associated electronics does is ring a  bell to indicate when the  player has lost. The version described here  has  a few extra features to make things a bit more  exciting, adding a  time limit to the game and a ticking sound during play. </div>
<div style="text-align: justify;">
<br /></div>
<div>
</div>
<div style="text-align: justify;">
Two 555 timer ICs  are used to provide these  functions. IC1 is configured as a monostable  which controls the time allowed for the  game, adjustable using  potentiometer P1. IC2  is a multivibrator to provide the ticking and Two  555 timer ICs are used to provide these  functions. IC1 is configured  as a monostable which controls the time allowed for the  game,  adjustable using potentiometer P1. IC2  is a multivibrator to provide  the ticking and he continuous buzz that indicates when the  player has  touched the wire with the hoop. </div>
<br />
<b>Circuit diagram :</b><br />
<span style="color: black;"><a href="http://lh3.ggpht.com/-zLnu_s4NTSM/T5RWj6OfH5I/AAAAAAAAFJM/EZPeqXsHovg/s1600-h/Wire%252520Loop%252520Game-Circuit%252520Diagram%25255B5%25255D.png"><img alt="Wire Loop Game-Circuit Diagram" border="0" height="249" src="http://lh5.ggpht.com/-LbPtm9-Le_U/T5RWlmZS9eI/AAAAAAAAFJU/i0X7gBBpsb4/Wire%252520Loop%252520Game-Circuit%252520Diagram_thumb%25255B3%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Wire Loop Game-Circuit Diagram" width="450" /></a></span><br />
<div align="center">
<b>Wire Loop Game Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div style="text-align: justify;">
When the monostable is in its  steady state,  the output of IC1 (pin 3) is low. T1 acts as  an  inverter, and D2 is thus forward biased.  R8 and R4 are therefore  effectively in parallel, with the result that IC2 produces a low audible  tone. The value of R4 is considerably  greater than that of R8, and so  the frequency  of the buzz generated by IC2 is chieﬂy deter-mined by the  value of R8.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
When the monostable  is triggered, the high  level at the output of IC1 is again inverted   by T1. D2 is reverse biased and so R8 is effectively removed from the  circuit. The frequency of IC2 is now largely determined by  the value of  R4. The ratio of R4 to R5 and the  value of C4 affect the mark and  space periods for the multivibrator: for a satisfactory  ticking sound  short pulses with long gaps  between work well. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Whether  a sound is produced also depends  on the voltage on pin 4 of IC2. When  the 9 V  supply is connected the monostable is initially inactive and  there is no voltage across  C1. Pin 4 (reset) on IC2 is thus low and no  tone  is produced. IC1 is activated by a brief press of  S1, which  generates a low-going trigger signal  on pin 2 to start the game. C1 now  charges via  D1 and IC2 is allowed to oscillate, generating  the  ticking sound. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The  pulse width of the monostable sets the  game duration, and can be  adjusted using  P1. If the allowed time expires, or if the reset  input  to IC1 is taken low (which happens when the hoop touches the wire), the  monostable  returns to the quiescent state. This causes IC2  to generate  the low buzz sound. D1 is now  reverse biased and C1 discharges through  the  relatively high-valued resistor R9. After a few  seconds the  voltage across C1 falls sufﬁciently  that the buzz stops and the circuit  is ready for  the next player. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The  circuit can be built ﬁrst on a breadboard,  so that the component  values can easily be changed to suit particular preferences for  game  duration and buzz pitch. When suitable  values have been selected the  circuit can be  built more permanently on a printed circuit  board. The  author used a sheet of plywood  to form a base for the game, the twisted  wire  being ﬁxed to the board and wired to the electronics mounted  below it. </div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/wire-loop-game.html" target="_blank">Streampowers</a></span></div>
</div>
</div>
</div>
</div>

Wire Loop Game

In the ‘Wire Loop Game’, a test of dexterity, the player has to pass a metal hoop along a twisted piece of wire without letti...

Railway Points Sequencer

Choice and Hobby 08:39

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4510397460932644889" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4311963750444905994">
<div align="justify">
Dedicated  model rail enthusiasts using sophisticated train and points controllers  often have the problem that as their layouts get bigger and more  complex, the transformer supplying power to the points does not have  enough current to switch several points at the same time. The actuators  in the points are designed for ac operation so it doesn’t help by  rectifying the supply and adding reservoir capacitors, the coils can  overheat and burn out if they get jammed during their travel (ac  operation actually helps to overcome friction in the mechanism). The  circuit shown here solves this problem by using a sequencer to ensure  than only one points actuator can be active at any point in time. During  operation the controller will switch all the points on one line at the  same time as usual, but the other connection to each coil is connected  to the sequencer unit. This circuit will only allow current to ﬂow  through one coil at a time. </div>
<div align="justify">
<br /></div>
<div align="justify">
<b><span style="color: blue;">Circuit diagram :</span></b></div>
<div align="center">
<a href="http://lh4.ggpht.com/-53MSMNNuiKM/TmkHXEHiVMI/AAAAAAAADnE/y4BdZ_feLOI/s1600-h/Railway%252520Points%252520Sequencer%252520Circuit%252520Diagram%25255B5%25255D.png" target="_blank"><img alt="Railway Points Sequencer Circuit Diagram" border="0" height="394" src="http://lh5.ggpht.com/-iwEny6-PraY/TmkHe5SwFTI/AAAAAAAADnI/bXNf6w9xUVM/Railway%252520Points%252520Sequencer%252520Circuit%252520Diagram_thumb%25255B3%25255D.png?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="Railway Points Sequencer Circuit Diagram" width="220" /></a> <b>Railway Points Sequencer Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
The sequencer circuit consists of a 555 timer  conﬁgured as an astable multivibrator clocking a 4017 Johnson counter  where the ten outputs are used to switch ten triacs in sequence, enough  for ten sets of points. P1 alters the oscillator frequency of the 555  timer and can be adjusted so that each time interval of the sequencer is  long enough to allow the points to switch. </div>
<div align="justify">
<br /></div>
<div align="justify">
The switching time varies depending on the  type of points but is typically between 1 s and 1.5 s. Any points that  jam during switching give out a characteristic humming noise in time to  the switching frequency so it makes them easier to ﬁnd. The eleventh  output of the 4017 can be connected to an LED (together with a series  resistor). This will flash to give a visual indication of the sequencers  operation. Power for the circuit is provided by 15 V ac from the points  transformer. The B80C1500 bridge rectifier (80 Vpiv, 1.5 A) and  regulator IC1 produce a stabilised 12 V for the circuit. Current  consumption is only a few milliamps.</div>
</div>
</div>
</div>
</div>

Railway Points Sequencer

Dedicated model rail enthusiasts using sophisticated train and points controllers often have the problem that as their layouts ge...

Heart Rate Monitor

Choice and Hobby 08:38

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-4098645867870266776" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-8467323260183249389">
<div align="justify">
Strictly  speaking, this simple circuit shouldn't work! How could anyone expect  an ordinary light dependent resistor photo cell to 'see' through a  fingertip in natural daylight and detect the change in blood flow as the  heart pulsates? The secret is a high gain circuit, based on a dual op  amp IC which can be either the low power LM358 or the JFET TL072. The  LDR is connected in series across the 9V battery supply via a 100kO  resistor (R1) and the minute signal caused by the blood pulsing under  the skin is fed to the non-inverting (+) input, pin 3, of IC1a via a  0.µF capacitor.</div>
<div align="justify">
<br /></div>
<div align="justify">
Pin 3 is biased by a high impedance voltage  divider consisting of two 3.3MO resistors. The feedback resistors to pin  2 set the gain to 11 times. The output of IC1a is fed via a 0.47µF  capacitor and 220kO resistor to IC1b. This is configured as an inverting  op amp with a gain of 45 so that the total circuit gain is about 500.  The output of IC1b is used to drive an analog meter which may be a  multimeter set to the 10V DC range or any panel meter in series with a  resistor to limit the current to less than its full-scale deflection.  The prototype used an old VU meter with a 47kO resistor fitted in  series.</div>
<div align="justify">
<br /></div>
<div align="justify">
<b>Circuit diagram:</b></div>
<b><a href="http://lh6.ggpht.com/-7YRYX_trnkk/TmkWH6N1dZI/AAAAAAAADoA/PbbrgJO79Ro/s1600-h/heart-rate-monitor%252520circuit%252520diagram%25255B6%25255D.jpg"><img alt="heart-rate-monitor circuit diagram" border="0" height="260" src="http://lh6.ggpht.com/-WihHzxwMjTM/TmkWKKAsPLI/AAAAAAAADoE/MJfyH8pf7vo/heart-rate-monitor%252520circuit%252520diagram_thumb%25255B4%25255D.jpg?imgmax=800" style="border: 0px none; display: block; float: none; margin-left: auto; margin-right: auto;" title="heart-rate-monitor circuit diagram" width="500" /></a></b><br />
<div align="center">
<b>Heart Rate Monitor Circuit Diagram</b></div>
<div align="center">
<br /></div>
<div align="justify">
Note that the unit was designed to use the  Dick Smith Electronics light dependent resistor (Z-4801). Other LDRs may  require a change in the value of resistor R1. A light source such as a  high brightness LED is not required. All that is needed is a reasonably  well-lit room, preferably natural daylight, to produce a healthy swing  of the needle. Only when the hands are very cold does it make it a  little more difficult to accurately count the pulses. To check your  heart rate, carefully position your thumb or finger over the LDR and  count the meter fluctuations for a period of 15 seconds. Then multiply  the result by four to obtain your pulse rate. The circuit can not be  used if you are walking or running, etc.</div>
<div align="justify">
</div>
<div align="justify">
</div>
<div style="text-align: right;">
<br />
<br />
<br />
<span style="color: black;"><a href="http://streampowers.blogspot.com/2012/07/heart-rate-monitor.html" target="_blank">Streampowers </a></span></div>
</div>
</div>
</div>
</div>

Heart Rate Monitor

Strictly speaking, this simple circuit shouldn't work! How could anyone expect an ordinary light dependent resistor photo cel...

Pulse Generator And Signal Tracer

Choice and Hobby 00:22

Pulse Generator And Signal Tracer

Dual-purpose test-instrument, Very simple circuitry, 1.5V Battery-operated This simple circuit generates narrow pulses at about...

Electronic Cricket Match Game

Choice and Hobby 00:20

<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="post-header">
</div>
<div class="post-body entry-content" id="post-body-59482809795491767" itemprop="articleBody">
<div dir="ltr" style="text-align: left;">
<div dir="ltr" style="text-align: left;">
<div style="text-align: justify;">
This  electronic cricket is a present for Kids. This simple battery  powered  circuit can be used to play Cricket Match with your friends.  Each LED  in the circuit indicates various status of the cricket match  like  Sixer, Run out, Catch etc. The Circuit uses two ICs ,one in the  Astable  mode and the second in the display driver mode. IC1 is wired as  an  Astable Multivibrator with the timing elements R1, R2 and C1. With  the  shown values of these components very fast output pulses are  generated  from the Astable.<br />
<br />
Output from IC1 passes into the input of IC2 which is the popular   Johnson Decade counter CD4017. It has 10 outputs. Of these 8 outputs are   used. Output 9 ( pin9) is tied to the reset pin 15 to repeat the  cycle.  When the input pin 14 of IC2 gets low to high pluses, its output  turns  high one by one. Resistor R3 keeps the input of IC2 low in stand  by  state to avoid false indications.</div>
<br />
<b>Electronic Cricket Circuit Diagram</b><br />
<div style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdOtlTXXu99yUdjSuO5wQwtIr111V6Ij5XKWyNrKK3mK8gfCpSurFXsSlviC4E7_AKKnyAJ5vWjoOLZAXF7fp5MOHOTA-BdqMYAE03plugc-JxSONkp_iYzK6jsmKdTmzxKT39qMPJAgk/s1600/Electronic-Cricket-Circuit-550x402.png" style="margin-left: 1em; margin-right: 1em;"><img alt="Cricuit Project: Electronic Cricket Match Game " border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdOtlTXXu99yUdjSuO5wQwtIr111V6Ij5XKWyNrKK3mK8gfCpSurFXsSlviC4E7_AKKnyAJ5vWjoOLZAXF7fp5MOHOTA-BdqMYAE03plugc-JxSONkp_iYzK6jsmKdTmzxKT39qMPJAgk/s1600/Electronic-Cricket-Circuit-550x402.png" title="Cricuit Project: Electronic Cricket Match Game " /></a></div>
</div>
<div style="text-align: justify;">
When  the Push Switch S1 is pressed momentarily, the Astable operates and   all the LEDs run very fast sequentially. When S1 is released, any one   of the LED stands lit which indicates the status of the match. For   example, if LED D7 remains lit, it indicates Sixer and if LED 8 remains   lit, it indicates Catch out. Label each LED for its status as shown in   the diagram. Pressing of S1 simulates Bowling and Running LEDs  indicates  running of Batsman.</div>
<div style="text-align: justify;">
</div>
<div style="text-align: justify;">
</div>
<div style="text-align: right;">
<a href="http://streampowers.blogspot.com/2012/08/electronic-cricket-match-game.html" target="_blank">Streampowers </a></div>
</div>
</div>
</div>

Electronic Cricket Match Game

This electronic cricket is a present for Kids. This simple battery powered circuit can be used to play Cricket Match with your fri...

Receive all updates via Facebook. Just Click the Like Button Below...