I have received some info from Ian Bird on his “Baby Paws (pause)” timer circuit – “In brief: This small, 2 ¼” by 1″ circuit board is based on a 555 timer chip and a resistor/capacitor combination. It can output a positive (+ve) signal and provide a switched ground for a short time period after being triggered. The trigger can be either a +ve feed or a ground connection. The delay is adjustable using a small screwdriver between milliseconds to more than 10 seconds. Changing two components can make this delay a lot longer, minutes or even hours or days.
- Operates using a voltage of between 5 and 15 volts.
- Polarity protection (optional).
- Facility for onboard voltage regulator (optional).
- Trigger from either a +ve voltage or ground.
- Will output a +ve signal (max 100ma) on triggering.
- Will supply a ground (max 100ma) on triggering.
- Delay adjustable from almost nothing to 10 seconds or more.”
Ian’s site will be up in the future detailing this and his other projects.