I started out using a single pole, single throw pushbutton switch from an old mouse for the switch on my Joule Thief with timeout circuit. But I changed it to a double throw switch. It’s simple to use the single throw switch to charge or discharge the timing capacitor and start the timeout. But if the switch is unprotected and gets activated accidentally, then it will never allow timeout and the battery will be wasted and eventually go dead.
To prevent this, I changed the switch so that if it is pressed, the capacitor is charged but the circuit is not activated. When the switch is released, the capacitor is then connected to the circuit and the timeout begins. If the switch is accidently pressed and held, the circuit will never be activated and the battery will not be discharged.
The pushbutton switch comes from an old ball mouse and already has the double throw terminal. The NC or normally closed terminal connects to the circuit, the NO or normally open terminal connects to the charging or discharging voltage, and the common terminal connects to the capacitor. This is all a simple matter of rewiring the switch, and does not require any additional parts.
This switching method applies to any battery operated circuit where there is a possibility of accidental discharge.
Back to experimenting…
