Introduction: DIY Clap Switch

Simple DIY switch for 12V lamps. Activate with a clap, turn off with another clap.

Step 1: Purchase Parts for Switch

Can purchase the parts individually or buy the kit from sites on the internet. I personally bought the kit from

The parts needed to build the switch are:

4 x 1K resistor

5 x 10K resistor

3 x 2.2K resistor

3 x 4.7K resistor

1 x 470 Ohm,

1 x 47K

1 x 470K

2 x 1N4148 diode

2 x 1N4001 diode

1 x PC817 optocoupler

1 x LM7805 voltage regulator

1 x BD139 NPN transistor

1 x SPDT switch

1 x 3mm LED

4 x 0.1uF capacitor (code- 104)

1 x 0.01uF capacitor (code- 103)

4 x S9013 NPN transistor

1 x 5mm LED

1 x Electret microphone

1 x 2 pin screw terminal

1 x DC barrel

1 x 500mA PTC resettable fuse

1 x 3 pin screw terminal

2 x 10uF electrolytic capacitor

1 x 47uF electrolytic capacitor

1 x 1uF electrolytic capacitor

1 x 5V relay

1 x 9V battery connector

Step 2: Solder Parts to Board

Easy enough. Solder parts to the correct parts in board. Schematic is included for the arrangement. Make sure each resistor is correct, and that the polarity of some parts is aligned right.

Step 3: Splice Wires From Lamp

Take the wire from a lamp or light-bulb and strip one section. Take ONE of the two wires (while unplugged) and cut it. Take the two freshly cut ends and solder a piece of wire to extend the size of the ends.

Step 4: Connect Switch to Lamp

Take the ends of the wires soldered to the lamp and connect them to the terminal on the switch. Should plug one into the NO on the terminal and one to the COM. Then tighten the screw on the terminal to lock the wires into place.

Step 5: Hook Up to Electrical Source

I used a DC Power Supply for this. It should be around 12V of electrical. Can connect through the nodes on the side or the port also on the switch.

Step 6: Clap!!

Each clap should be indicated by a flash from the LED. Once the second LED activated the lamp should be turned on. Simply clap to turn it off again.