04-08-2019, 03:06 PM
There is a 4 Pin JST Connector just behind the Power DC Jack .... its directly connected to the power rail ... you could rig a simple circuit up completely independent of the GPIO using a 555 Timer some resistors, a tranny and and capacitors etc even safer install your own buck converted to drop the voltage down to be even saver. But I take it you wanted GPIO / PWM to avoid the complicated electronics !