MK139 - Clap on/off Switch

Built my first Velleman kit and it worked perfectly - the first day. After removing power from an AC adapter and switching to battery power, the relay no longer activates.

Nothing was done in the interim.

The clap LED lights with sound but no relay. If power is left on for a few minutes, the relay activates without sound stimulus and both LEDs stay lit.

Any suggestions?


Either there is a mechanical problem (loose or bad soldering, loose or bad contact, etc…) or the battery voltage and/or capacity is off spec.

Thanks - same issue with AC adapter, 12 vdc, 500 MA. Will go back and check soldering but it’s weird that it worked perfectly initially.

Must have been a solder connection - I thought they all looked good but went over all of them and voila!