Feature: 1. Better Control: With this voice switch module, you can easily control the switch just by clapping your hands, suitable for DIY. 2. Stable Working: Q1 and Q2 composed of two audio amplifier circuit, the audio signal is accepted by the MK1, C1 is coupled to the base of Q1 pole, amplified and fed directly from the collector to the base of Q2 to a negative square wave at the collector of Q2, with to trigger the bistable circuit. 3. Great Accuracy: R1, C1 circuit frequency response is limited to about 3kHz to high sensitivity range. The power is turned on, the state of the bistable circuit Q4 off, Q3 saturated, D3 does not shine. 4. Efficient Work: When MK1 received control signal, and a negative square wave output after two enlarged, negative spikes through D1 add to the base of Q3, the circuit rapidly flip, D3 is lit after differential processing. 5. Quick Response: When MK1 again connected to the control signal, the circuit and flipped, D3 is off. Circuit board reserved for the terminal J1 access outside the control equipment and other devices through the J1 connector relay voice. Then relays required at both ends of the relay coil anti and a diode. Specification: Item Type: Voice Switch Module Working Voltage: 5V PCB Size: Approx. 28 x 49mm / 1.1 x 1.93in. Package List: 1 x Voice Switch Module Kit