Many of our Defusable Clock customers use the device in Airsoft competitions where participants must find the device and defuse it before the timer expires. A great thing to do in these games is to trigger a loud siren or smoke grenade when the timer reaches 00:00. The new version V2 of the clock has a connections for such a trigger and we are now selling relay modules in the nootropic design store.
Below is a picture that shows how to connect a relay. The red wire is 5V and if you have an older kit it needs to be soldered to the output pin of the voltage regulator. It then connects to the 5V red wire on the relay module. The 5V output is the rightmost pin of the voltage regulator when looking at the front of the board. The green wire is the trigger connection and goes to the green wire on the relay module. The trigger ground connection is the black wire going to the relay module.
UPDATE: there is now a 5V pad next to the trigger and ground pads that you can use:
To send 9V to your destination device like a siren or smoke grenade, connect a wire to the + connection near the power connector, and a ground wire to the – connection. These are shown as yellow and black wires in the picture. This assumes you have a 9V input voltage to the clock. If you are using a different voltage like 12V or a 7.4V lipo battery, that’s fine. This is the voltage available on the + connection.
The black ground wire connects directly to your device. The positive voltage (yellow wire) connects to the relay module terminal marked “COM” (for “common”). The gray wire in the picture is connected to the relay terminal marked “NO” (for “normally open”) and this wire is the positive voltage to your siren or smoke grenade or whatever.
When the countdown reaches 00:00, the trigger voltage (green wire) will cause the relay to close and connect the 9V yellow wire to the gray wire, thus providing 9V to your external device for a duration of about 2.5 seconds while the clock goes through the “detonation” sequence. If you want power to be disconnected when the countdown reaches 00:00, connect the gray wire to the terminal marked “NC” (“normally closed”) instead.
Have fun, and as always, stay out of trouble!