The clap switch circuits explained here will toggle a connected load ON and OFF in response to alternate clap sounds? Here I have explained 4 unique and simple designs which can be selected as per user preference.
The article talks about what the title suggests – a clap switch. A small electronic circuit when built and integrated to any electrical appliance can be made to switch ON/OFF through mere hand clapping.
The proposed design when integrated to any of your electrical appliance can be used to switch it ON and OFF simply through alternate clapping of your hand.
The device becomes more interesting and useful because it does not require any external mechanism or device to carry out the specified operations.
NOTE: An IC 555 circuit can never produce an alternate ON/OFF switching for the load. Instead they will work like monostables and switch ON the load only for sometime and then switch it OFF. So please stay away from cheap misleading circuits online.
Main Application Areas
The main application of the clap switch circuits described below is for controlling home appliances like light bulbs and fans.
Suppose you want to connect a ceiling fan with this circuit so that you can switch it ON or OFF with alternate clap sound, you can easily do it, by wiring the fan 220 V AC input through the relay of the circuit.
Similarly, if you wish to switch a tube light or any 220 V or 120 V AC lamp, just wire it in series with the relay of the clap switch.
The following image shows how to connect fan with the relay
The fan regulator can be connected anywhere in series with the wiring.
Any light bulb can be connected with the clap switch relay as given in the folowing figure
How Sound Vibrations Trigger the Circuit
As you must have noticed the clapping of hands creates a loud sound and is sharp enough to move quite a distance.
The generated sound is in fact strong ripples or vibrations created due to the sudden compression of air in between our striking palms.
A mic is connected to the amplifier stage; the sound vibrations made by clapping hits the mic and get converted into tiny electrical pulses. These electrical pulses are amplified to suitable levels by the transistors or IC and are fed to the flip/flop.
The flip flop is a bistable relay circuit which switches ON/OFF the attached relay alternately in response to each clap sound.
The circuit presented here is basically made up of two stages, the first stage is a two transistor hi-gain amplifier and the second stage consists of an efficient flip/flop.
The flip/flop stage alternately switches the output relay driver in response to every subsequent clapping. The load connected to the relay thus also gets activated and deactivated correspondingly.
The circuit may be further understood with the following explanation.
1) Clap Switch Circuit Using IC 741.
The above clap operated relay circuit was provided to me by one of the keen readers of this blog Mr. Dathan.
The circuit is very easy to understand:
The opamp here is configured as a comparator, meaning it is positioned to differentiate the slightest of voltage differences across its two inputs.
When the clap sound hits the mic, a momentary drop of voltage is experienced at pin#2 of the IC, this situation raises the voltage at pin#3 of the IC for that instant.
As we know, with pin#3 at higher potential than pin#2 makes the output of the IC high, the condition puts the output of the IC go high momentarily.
This high response triggers the IC 4017 pin#14, and forces its output to either move from pin#2 to pin#3 or vice versa depending upon the initial situation of the outputs.
The above action switches the load accordingly either to ON or OFF position.
The above 12 V clap triggered switch circuit using IC 741 was successfully tried and tested by Mr. Ajay Dussa. The following prototype images for the same were sent by Mr. Ajay.
The PCB design (track layout) for the above can be seen below, as designed by Mr. Ajay:
2) Clap Switch Using Transistors or BJTs
In the above explanations I have explained a simple clap activated switch circuit which incorporated an IC for implementing the desired ON/OFF toggling actions. The present design uses a different principle and utilizes only transistors for the above triggering actions.
Clap Switch Video Demonstration
Parts List
- R1 = 5k6
- R2 = 47k
- R3 = 3M3
- R4 = 33K
- R5 = 330 OHMS
- R6 = 2K2
- R7 = 10K
- R8 = 1K
- R9, R10 = 10K
- C1, C4 = 0.22uF
- C2 = 1uF/25V
- C3 = 10uF/25V
- T1, T2, T4 = BC547
- T3 = BC557
- All IC diodes = 1N4148
- Relay diode = 1N4007
- IC = 4017
- Relay = 12v / 400 ohms
How it Works
The figure above shows a straight forward two stage sound activated switch.
The first stage comprising T1, T2, and T3 forms a hi-gain common emitter amplifier configuration.
A mic is connected at the base of T1 via blocking capacitor C1.
Strong sound vibration hitting the mic is instantly picked and converted into tiny electrical pulses.
These are in fact small AC pulses easily make there way through C1 into the base of T1.
This creates a kind of push-pull effect and T1 also conducts in the corresponding way.
However the response of T1 is relatively weak and requires further amplification.
Transistors T2/T3 are introduced exactly for this and help to improve the voltage peaks created by T1 to appreciable levels (almost equal to the supply voltage.)
The above voltage pulse is now ready to be use for toggling the relay ON/OFF and is fed to the relevant stage.
IC 4017 as we all know produces sequential shifting of its output pin-outs (logic high) in response to every positive pulse at its clock input pin 14.
The amplified clap sound voltage pulse is applied to pin 14 of the above IC, this flips the output of the IC to either a logic high or a logic low depending upon the initial status of the relevant pin-out.
This triggered output is appropriately collected at the diode junctions and used to toggle a relay through a relay driver transistor T4.
The relay contacts ultimately goes to a load or an appliance which is correspondingly switched ON and OFF with every subsequent claps.
Using BJTs and Power Supply
Looking at the circuit diagram we see that the entire circuit has been configured around ordinary general purpose transistors.
The functioning of the circuit may be understood with the following points:
Transformer X1 along with the D1 and the capacitor C4 forms the basic power supply circuit for providing the required power to the circuit.
The first stage which includes R1, C1, R2, R3, R4 and Q1 form the input sensor circuit.
The next corresponding stages consisting of Q2 and C3 form the flip flop stage and makes sure that the signals from the input sensor stage is appropriately converted into alternate toggling of the output.
The output stage consists of a single transistor Q4. It is basically configured as a relay driver stage for translating the alternate ON/OFF actions from the previous stage into physical toggling of the connected load across the relay terminals.
The design is very old, I built it in my school days by assembling a kit. The circuit diagram using transistors is shown in below:
Parts List
- R1 - 15K
- R2,R5,R12- 2m2
- R10, R3 -270K
- R4 - 3K3
- R6 - 27K
- R7,R11 - IK5
- R8,R9 - 10K
- R13 - 2K2
- C3, C1 - 10KPF Disc
- C2,3 - 47KPF Disc.:
- C4 - 1000uF/16V;
- Q1,2,3,4 - BC547B
- D1 - 1N4007
- D2,3,4,5 -1N4148 _
- Xl - 12V/300mA Transformer .
- MIC - Condenscr Mic
- RLY — 12V Single Charge over relay
Another version of the above can be seen in the following diagram:
3) Double Clap-Clap Switch Circuit
All the clap-on switch circuits explained above have the ability to operate only with single alternate clap sounds.
This feature makes the circuit vulnerable to external sounds which might occur occasionally triggering the connected load with the circuit.
A double clap operated circuit thus becomes more suitable and resistant to spurious triggering due to the fact that it would toggle only in response to two subsequent clap sounds instead of one.
The explained circuit is simple yet effective and does not employ microntrollers for the implementation unlike other circuits on the net.
The circuit has been tested by me, but it is a fairly complex design it's important to first understand the stages convincingly, and then build it to avoid failures.
Circuit Operation
The proposed clap-clap circuit or double clap circuit functioning may be understood with the following points:
The lower stage is basically a simple sound activated switch circuit which would activate with any loud sound.
The IC 741 is rigged like a comparator with its pin#2 referenced at some optimal fixed potential determined by the setting of the given preset VR1.
Pin#3 of the IC becomes the sensing input of the IC and is connected with a sensitive mic.
The adjoining IC 4017 is a bistable stage which activates the connected relay driver stage and the load alternately in response to every positive high pulse at its pin#14.
When a loud sound such as a "clap" hits the mic, it momentarily grounds pin#2 of the IC741 resulting in a momentary high pulse at its pin#6.
If we connected this output to pin#14 of IC4017 would have resulted in an instant toggling of the load with every single sound input which we don't want here to happen, therefore the response at pin#6 of IC741 is broken and diverted to an IC 555 monostable stage.
How IC 555 is Configured
The IC 555 circuit is rigged in such a way that when its pin#2 is grounded, its output pin#3 becomes momentarily high for some period of time depending upon the values of the 10uF capacitor.
When a sound hits the mic, the high pulse from IC741 output triggers the BC547 attached to pin2 of IC555 which momentarily grounds pin#2 of IC555, which in turn put its pin#3 high.
However the instantaneous high at pin#3 of IC555 takes a while to reach the connected BC547 due to the presence of the 33uF capacitor.
By the time the 33uF charges and switches ON the transistor, the potential at the collector of the transistor is already gone due the absence of the clap sound which happens only momentarily.
However with the application of the immediate subsequent clap provides the required potential at the collector of the transistor which is now allowed to the reach pin#14 of the IC 4017.
Once this happens the relay driver triggers or deactivates depending upon its initial condition.
The toggling of the load thus takes place only in response to a pair of clap of sounds making the circuit reasonably foolpoof.
Another Double Clap Switch Circuit
High pitched sound generated by clap of hands, click of fingers and a various other methods can be used to trigger the next circuit.
The design necessitates a minimum of two intense clap sound pulses to initiate the triggering.
This significantly minimizes the chance of unwanted haphazard switching of the device, due to spurious accidental sound.
The first sharp hand clap is detected by the electret microphone and is fed into operational amplifier ICI's inverting ( -) input at pin 2 via C1.
The signal negative peak at the pin 6 output of IC1 subsequently activates 555 timer IC2, that is set up like a monostable multivibrator.
The trigger signal reaching the pin 2 input of IC2 is internally extended to toggle the dual D flip-flop IC3. With the help of the three-state counter configuration of IC3.
Not one but two sharp clap sounds are necessary to create a positive output at pin 1 that causes Q1 into switch ON. When Q1 activates the relay and switches its contacts to N/O points.
Any electrical appliance attached to the relay's contacts now switches on.
As soon as pin 1 of IC3 becomes high, it continues to be in that situation until a subsequent two powerful hand claps hit the MIC to repeat and revert the condition.
Thus, it requires two loud sound inputs to switch off the electrical load hooked up to the relay's contacts after the circuit is activated.
Krish says
Can you make a circuit to make a sound by buzzer when it hear two claps with in two seconds, (limitations -> we can use only one 555 timer and can’t use any other IC’s)
Swagatam says
It may be possible by adding a transistor stage with 555, but the 555 output will be ON only for a few seconds, depending on the monostable RC values, and then toggle off, you cannot get bistable action in this circuit.
Krish says
Ok I am trying to design the circuit and it still tricky.
Please let me know if you design the circuit in Multisim or any other software and it will be helpful.
Swagatam says
I draw my schematics on Microsoft paint software.
Rosario says
Sir I reproduced his schema with Kicad. When checking the electrical rules I get the error: Input Power Pin not driven by an Output Power pins Pin 8 VSS 4017
Should I discard it? Thanks
Swagatam says
Hi Rosario, it may not be possible for me to suggest on the Kicad problem…but if you build the circuits practically I can assure you these will work perfectly and if there’s any issues I can solve them with a step by step troubleshooting.
Rosario says
I try to post the problem in the Kicad forum.
Can I show your schema? Do I have your authorization?
Swagatam says
Sure, you can post the diagram, if possible post the article link also so that the forum visitors will know from where the diagram is taken.
Paresh Rajput says
Sir can I get proper circuit working for clap switch using bjt and power source.
Swagatam says
Paresh, transistor circuit is already provided in the above article, you can refer to the following design:
https://www.homemade-circuits.com/wp-content/uploads/2012/04/clapswitch-1.jpg
zuzar padghawala says
Hi,
can you make & give a clap circuit to work on 9v battery, for 5mm – 5 leds (4 white & 1 RGB)
Swagatam says
Hi, do you want the LEDs to switch ON/OFF with every clap, or just momentarily ON with every clap?
Ikenna says
Thanks at Engr. Swaggatam.
Can the circuit use another source of power apart from battery ?
It drains battery easily .
Should I make a 9 volt power pack ?
Swagatam says
Hi Ikenna, you can power the above circuits with a 9V or a 12V AC to DC adapter.
Bios says
Hello Swagatam, its me Bios, the circuit looks so cool but the resistors 33k and 330 ohm are difficult to get, which value can I use instead. Sir
Swagatam says
Thank you Bios, Those values are not critical, slight difference will not have any effect on the working of the circuit. Alternatively you can try connecting assorted values in series and parallel combination to get the actual values of the parts.
DrZipZwan says
Hi, thx for thoses circuits, utiles projects as always 😉
Can I use IC TC4001 ,or IC TC4011, or IC TC4019, or IC TC4020, instead of IC 4017??
I would like to know because, those are the model I got a disposition.
Thx you.
Swagatam says
Hi, thanks, do those alternatives have a sequential response to input clocks? If yes then they can be used. I think 4020 is OK, but not 4001, or 4011
DrZipZwan says
Thx you, but wow, your question is a bit complicated for me. I guess I ll go with 4020, and hope it works ))
Swagatam says
No problem, you can use 4020
Mahasetra says
Hi, First, thanks for the circuits.
I want to do the doucle clap circuit using a LM358 so
1- can I power it using a 9V Battery? I don’t have symetric power supply
Also, as the LM358 has 2 op amp, then
2- can I use one part of LM358 for an non-inverting amplification then one part like a comparator? Or is the amplification useless?
The mic will be at 1,5meter of the circuit meaning there will be some loses.
Swagatam says
Hi, thanks for liking this circuit.
You can power it from 9V battery but the relay must be also rated accordingly so that the battery doesn’t drain quickly.
No extra op amp is required, since the first op amp itself will be sufficient for amplifying the MIC, even if it is wired at some distance
Lawal Mohammed says
Please Sir could you guide me to use it as a final year project work?I needed a clapswitch to be made with a password such that only the owner have access to use it.
Swagatam says
Lawal, how would you use the password with the clap switch?
Lawal Mohammed says
Please Sir, I assume by combining a four
output clapswitch with a four key password switch, with the clapswitch changing its outputs with upon a single clap and each changing output activates the password switch. The password switch are numbered in a written form .So by varying the number of claps to activates each of the different
four keys of the password switch, for example 2,4,1 and 3 orderly but successive number of claps needed to activate the four keys of the password switch to activate the clapswitch
Swagatam says
It is possible but will require 4no IC 4017, and 4 small SCRs, and other parts.
Lawal Mohammed Abubakar says
Thank you Sir, I am very grateful for your response. Please Sir could you send me with the design to experiment on.I needed build it as my final year project work.
Swagatam says
Hello Lawal, I have designed the basic first stage, once this is confirmed by you, you can replicate 3 more similar stages with slight different modifications:
The RC diode network shown at pin#2 should be repeated at pin#7 also.
This stage is for 2 claps code.
The circuit is supposed to work in the following way:
When two claps are made relatively quickly, the 4017 output logic reaches at pin#4. Here the user has to wait for a few seconds until the SCR gate capacitor charges fully, and the SCR latches to switch ON the next 4017 IC.
Now suppose the person who does not know the 2 clap code for this first stage, he will try to clap quickly, moving past pin#4 and reach pin#10 of the IC, which will cause a permanent latching of the IC due to the connection of pin#10 with pin#13.
If the person tries to clap with delays, then the logic at pin#2 will cause the 100uF to charge and send a positive pulse to pin#15 of the IC which will keep resetting the IC back to pin#3.
Suppose the person claps initially quickly and then stops at pin#7 then again the circuit get reset due to the relevant RC/diode network.
The same concept will need to be repeated for the other subsequent IC 4017 with the other specified code numbers, accordingly.
Malphas says
Hi,
I’m trying to make a bass drum flash (a 230v 30wLED that lights up only when i hit the drum and then turns off) is it possible to do this with a piezo transducer and a solid state relay? As follows:
—— -12vDC —>|———–|| | S.S.R.|
—— +12vDC—>|———–|<——————-• L
Am i missing anything?
I am awaiting your answer.
Thank you for your time!
Swagatam says
Hi, it is possible, but the solid state relay is not required, instead a transistor driver will be enough:
Ndukwe Prince says
hi, sir i designed the second circuit which requires transistors… i assembled all component on my Vero board, i’m using a 9v battery with a 12v relay. my problem is once my circuit comes on, my LED come on too and if i make a clap it doesnt go off, pls sir i need a response to why its not responding and i’m connecting directly to my 240v light blud.
i would be glad if you reply me
thanks
Swagatam says
Hi, as you can see in the video the circuit works perfectly and there’s hardly anything complex in the second design.
You can remove C2 and check the response again….C2 is for delaying the switching OFF action of the relay and the load.
Ndukwe Prince says
thank you sir, but i have one more question. is it necessary for the led on circuit board to turn off when you clap?
Swagatam says
The LED must turn ON momentarily when you clap…please see the response of the red LED in the video
Ndukwe Prince says
Mine is comes ON, when i attach my 9volt battery. And if i clap i won’t go OFF.
Is there an adjustment i need to make
Samuel says
Although impressive thumbs up, but it seems that 4017 can be removed from this circuit without losing the 2 clap on – 2clap off function. Don t u think so ?
Swagatam says
Thank you! without 4017 the output will not lock ON/OFF, it will be momentarily ON and then switch OFF
Trishpota says
Dear swagatam
Double clap switch is working from circuit’s near.What can i use about improving distance for mic?(I adjust trimpot) Is mic amplifier just enough?
Swagatam says
Glad you could make it successfully. You can try the transistor circuit and replace the 741 circuit with it. Use the T3 collector to feed the transistors of the IC 555 monostable. Ignore the relay at T3 collector
Trishpota says
It works but very sensitive i want adjust sensitive what should i do?(using pot?where?) i tried extended charging time(using 47uf it gains to me 2m 30sec ,4.7uf gains 15sec)
Swagatam says
You can try adjusting (increasing) the series resistor which is connected between the MIC and the positive supply
Danquah says
Have you tested the double clap switch….my is not working…
Swagatam says
It will work, if you do it patiently and stagewise. You will have to separate the upper and lower stages, and test them separately, also you will have to connect a few LEDs across some specified points which will provide you with a clear indication regarding the sequential operations, and help you to optimize the timing for the two claps….possibly I may update the modified diagram soon
Sherwin Baptista says
Hello sir,
To be more precise,
1. On idle, the circuit when powered, must keep the load shut until we clap.
2. Upon a single clap, the clap switch circuit should respond but should hold the relay ‘ON’ and the load should operate without interruption.
3. Now, by clapping again, the load must not go off rather we will manually shut the load off using a switch against the load.
This circuit is a bit different in operation, i have stressed on “by clapping again, the load must not go off” please keep this in mind.
I hope you understood now requesting you to help me.
Thanks
Swagatam says
Hello Sherwin, guess why I told you to add the 1K resistor for C2? It is to latch the relay on the first clap, and I also suggested that to reset the circuit you must short the emitter/collector of T1.
So it is exactly as per your requirement.
Sherwin Baptista says
Good morning Sir Swagatam,
One small request, could you please link me to the page of a particular clap switch circuit where,
1. upon a single clap the clap switch circuit responds and the load operates.
2. to switch off the load, we will manually control an on/off switch.
I hope you understood, i want a one way clap switch circuit which only will trigger the load (ON) one upon a single clap action and to switch off the load we will physically control the switch to (OFF).
Please do help me with the appropriate circuit,
Thanks,
Swagatam says
Hi Sherwin, you can try the first circuit from this article:
https://www.homemade-circuits.com/simplest-sound-activated-relay-switch/
just replace C2 with a 1K resistor.
Swagatam says
..to reset short the collector/emitter of T1 manually
Arnold Engineer says
Hi sir. I made the 1st circuit using IC 741 but i doest work. I only connect two pin of VR1 1k. Is it correct? I cant fine the problem. Plss help me. I can send you my circuit photo if you want. Plss reply ser
Swagatam says
Hi Arnold, it is a straightforward design and will work. You can use two pins of the pot, but the center lead of the pot is compulsory among the two leads.
I would recommend a preset and not a pot because adjusting a pot can’t be accurate.
You just have to adjust the preset such that the voltage at pin3 of the op amp is slightly lower than the voltage at pin2. You can also a add a red LED in series with R4 to check the output response from the op amp to clap sounds
Elias - Brazil says
I would like to thank you for clap circuit 1). I am a hobbyst and tested it. As I had lm301 used instead 741. Please inform if lm 301 can be used without any other changes in components.
Rgds
Swagatam says
Thank you, yes it can be used, in fact any op amp or comparator IC will work here!
Francis says
Hi Sir my name is Francis
Having combined the first circuit With 1 microfarad capacitor to pin 4 and ground, 10K resistor in series to pin 6 and 14, 10K resistor in series to pin 4 and 15 and 0.22 microfarad 50V capacitor to pin 15 and positive.
How much current does the circuit use?
Swagatam says
Hi Francis, the circuit may consume 10 to 15mA when idle, and upto 50mA while the relay is operational.
Francis says
1.Sir how can i further increase the sensitivity of the mic and can i use two micro phones or ill need to add or remove a component
2.Sir all the components plus the new new resistors and the capacitors plus the relay.maximum current is 50mA. Can a use a 9v1A power supply or any other please advise!
Thank You
Swagatam says
You can tweak R1 value to adjust the sensitivity of the circuit.
You can connect two MICs in parallel.
you can use 9V 1 A supply, just make sure the relay is also rated to work with 9V
Francis says
1. Sir if I’ll use two microphones do i need to change the value of the variable resistor?
2. Sir I tested the first circuit with the given components but the LED (ON) connected to the transistor would light first instead of the other LED (OFF). If I add a 1uF/25V, 0.22uF/50V and two 10K resistors just as you’ve explained to someone else above this problem will be solved? Please advise…
Thank you
Swagatam says
Francis, for two mics also the circuit will remain the same.
Which two LEDs are you referring to, I can see only one LED in the first diagram?? Where did you connect them?
Hobbyman says
I tried everything but it doesnt seem to work
i think the transistor circuit works perfectly
coz the LED goes off after 2 seconds
but the relay doesnt seem to work
what could be the problem? which part of the 4017 circuit is important for the relay? i mean which parts do i need to check first?
Swagatam says
I hope you have built the 4017 exactly as shown, with the 1N4148 diodes?
OK, now connect an LEd in series with the base of the relay transistor. This will quickly tell you whether the signal from the IC 4017 is correctly reaching the relay transistor or not. If the LED switches ON OFF but the relay doesn’t will mean the transistor is faulty. If the LED does not respond, short circuit the emitter/base of the relay transistor and check again, if now the LED responds then again it will prove the transistor is faulty.
I can’t anticipate any other fault right now, except if the IC 4017 itself is faulty,
electron says
Hi there
I could not find a bc547 in the market
i know its very common..its strange it wasnt available
anyway what is the best sub for it? i have plastic 2n2222 , bc546, bc 548 and bc 549
among these which one do u suggest?
Swagatam says
He electron, You can use BC546 which looks most appropriate among the mentioned devices.
Nikolas says
Hello sir
How you doin?
I have a question
How much mA does the second circuit need to work?
Swagatam says
Hello Nikolas, it will consume around 5 mA when the relay is not active, and around 50mA when active (or depending on relay specs.)
manushifin says
in reply to “Both will work, you can use any one of them”
yes but which one would u suggest?a 2.2k pot or a 4.7k pot?
Swagatam says
There will be no noticeable difference in the response, so I don’t have any specific suggestion, you can use the one which is available with you.
Hobbyman says
I just built this circuit
I used a 12v adapter as the supply
When I whistle the leds turns on and it goes off once I stop whistling
Also the 12v relay does not seem to turn on and off
I know there’s something wrong
I just don’t know what
Can you help me plz?
Swagatam says
It won’t respond correctly to whistle sound, it is designed to respond to low frequency loud sounds, like a clap sound.
You can try momentarily bypassing the emitter/collector of T3, and check if the relay responds or not. If it doesn’t respond then your 4017 circuit may be having problems, which you’ll need you troubleshoot by examining the connections
Hobbyman says
What if I’m the relay responded when I connect the e and c of t3?
Hobbyman says
Wait please ignore my last message
I didn’t get what you mean by bypassing the emitter or the collector of T3
U mean connecting base to emitter? Or collector to emitter
Swagatam says
it’s emitter and collector, not base….in other words Connect pin14 of IC 4017 with positive line momentarily, tapping it alternately should click the ON/OFF
Hobbyman says
the second circuit as you said has more sensitivity. but i cant see a pot on it
i wish there was a pot so that we could adjust the sensitivity
Swagatam says
you can use a pot for R6 or controlling sensitivity.
Hobbyman says
THANKS A BUNCH
A 2.2k pot?
Swagatam says
It will do, connect the center terminal with the base of the transistor.
manushifin says
should I use a 2.2 pot or a 4.7? which one works better sir?
Swagatam says
Both will work, you can use any one of them
Hobbyman says
is the positive of c2 connected to r4 or it is a jump?
Swagatam says
It is a jump, connected only to T2/R5…you can remove C2 because it will create a delay OFF on the load
Hobbyman says
C2 the 1uf cap? So if I remove the 1uf cap the relay will go off once I clap?
Swagatam says
yes, if you remove C2, relay will quickly respond to your claps, if C2 is included, you will have to pause for 2 seconds between each clap.
Stephi says
Hi.I want to make the first circuit
To get more safety Im planning to use a fuse for my 9v 300mA power supply.what fuse amperage do I need? 0.5a fuse or 0.3 or…? can I even use 1.6A fuse? will it cut the AC if the power supply is shortened?
Swagatam says
Hi, a fuse is actually not required, and the chance of your power supply getting shorted is almost zero. Still if you are interested you can put one on the AC side of the power supply, the rating will depend on the load or appliance that you connect with the relay contacts. If it’s a 0.5 amp lamp then the fuse could be rated at 1 amp and so on.
unknown says
hi sir…i really like your website
i always come here for %100 working circuits
i have a question about the circuit above
the first circuit
what is a good replacement for the 741 ic
i have TL081, TL061,TL071
Ive heard that the TL071 opamp is a low noise amp which i think does affect the circuit’s sensitivity right? but i dont know for sure if it can be replaced with 741 with no problem
the reason im looking for a replacement is i could not find a 741 ic at store
Swagatam says
Thanks oppa, I,m glad you liked my site!
You can actually use any op amp for this application. The low noise characteristic is not relevant to this application, since it is used only as a basic comparator, so basically you can use any op amp here, all will work
leesquin says
single clap circuit work flawlessly. I can adjust the sensitivity by ajdusting the pot or the aupply voltage.
Swagatam says
that’s great, I am glad it’s working!!
Hobbyman says
hello sir
i am very interested in this project
i want to make this circuit for my bedroom light…can u plz tell me which circuit has more range and sensitivity?
and about the second circuit…can i supply it with 9 volt power supply and replace the 12v relay with a 9v one?
the 4th circuit looks nice.. does it work properly? no offence…in my country these components are expensive
Swagatam says
Thanks Hobbyman,
The second circuit seems to have the longest range and high sensitivity. Yes it can be used with a 9V power supply and relay.
The 4rth circuit is yet to be tested but I am sure it will work once everything is adjusted perfectly.
Hobbyman says
Ok sir thank you
So in the second circuit, I can use 9v supply and 9v relay or 9v supply and 6v relay?
I’ll be back soon with a pcb so that it users who would prefer a pcb can use it
And I saw u said something about adding a 0.22 cap across pin 3 and 6 in order to get extra sensitivity, should I add it to my pcb?
Swagatam says
Hobbyman, I referred to this circuit not the first one:
https://www.homemade-circuits.com/wp-content/uploads/2018/08/clap-switch.jpg
This circuit is more sensitive.
For 9V supply you must use a 9V relay, not a 6V relay
vishnu says
hai Iam vishnu, sir I bulid a clap circuit using Bc547transistors without any Ic their are 3 transistor of Bc 547 and1transistor BAc368 without relay my circuit is completely worked first after some type it is not detect sound instead when we touch mic the LED wil ON&OFF .
Swagatam says
Vishnu, if you have built it on a breadboard then possibly there could be a loose contact somewhere, otherwise one of your transistors could have gone bad…BC547 are rated at minimum 60V so those may be fine but BC368 is rated at 20V only so may be you could test this transistor….and if you are using a relay make sure to use a freewheeling diode across the relay coil
Yanniverse says
I tried doing this project in breadboard but it doesn’t respond to my clap or any sound i made. the LED only lit, that’s it. what can be the possible problem in this one? I hope i could get a quick response, it is for our electronics project. Thank you and good day!
Swagatam says
first of all recheck all the connections, because breadboard are always prone to mistakes and loose connections.
if possible remake it on a veroboard by practical soldering.
If you are referring to the last circuit, remember the preset has to be adjusted carefully to get the results, otherwise the circuit won’t respond.
for testing the IC 741 response, remove the LED/resistor from the IC 4017 pin#3 and connect it across pin#6/ground of the IC 741.
Now after careful adjustment of the preset you should be able to see this LED becoming momentarily ON on each clap sounds.
aiwin anil says
YES IT WORKED,after a long time.Thank u for your instant reply.It is only because of your fast reply i could make it successfully.Now i have to make another project-amplifier circuit.Please suggest any website for this project which uses an ic,condenser mic and a 8ohm speaker(or any small speaker).
Swagatam says
I am glad to know it worked…congrats on that!
for MIC amplifier you can try the last diagram as given in the following article
https://www.homemade-circuits.com/2012/08/ic-lm-386-datasheet-explained-in-simple.html