/diy/ - Do It Yourself

>>2499654
MOSFET + RC circuit. Gate power to the entire circuit with a small-signal FET like the BSS138, tie the gate of the transistor to ground via a resistor and parallel capacitor, and connect them to VCC using a button. So when you press the button the cap charges up immediately and the FET turns on, but discharges through the resistor until the FET turns off. Adjust R and C to get 3s or so. Importantly the idle current is basically zero, so it won’t drain your battery. If you use an N-FET it needs to be between the load and ground.