I'm trying to adapt my Match Guns MGH1 (Air pistol with electronic trigger) to use trigger a laser when shooting. Currently the trigger circuit is driving a solenoid. The circuit board seems to have the trigger signal passing through a monostable multivibrator (NXP HEF4538BT) that drives a LL024N MOSFET, which in turn drives the solenoid. I don't want to use the trigger circuit to drive my laser directly as I don't want to introduce any noise in it and affect trigger performance.
I want to create a circuit, sharing power and the trigger signal, that upon trigger press (positive edge, trigger is pulled down), generates a pulse with time T, regardless of the time I press the trigger. I designed the following circuit:
The idea is that as long as I'm not pressing the trigger, the capacitor charges up through R2 and M5. When I press the trigger, the capacitor can discharge through R3 and M2. Doing an AND operation with the trigger signal and the voltage on the capacitor seems to produce the signal I want.
With the premise that this works as I see it, I would like to get rid of the NOT and AND gates with some 555 magic, or some simplification of this that I'm not seeing!
This all-FET version seems to also work, replacing the logic gates since the circuit wont have logic-level voltages.