Summary

Substitute AA battery for toys and electronic devices.

I made this to power any AA battery device from an AC power adapter (5V USB in my example)

Insert the wire (max. AWG 24) in the tiny holes, with a few mm protruding inside, then tighten the screw in the central hole to secure the wire in place.

The + terminal needs to be made with a short length of M5 threaded rod to replicate the small bump

The - terminal can be done with any 4.5mm conical head screw (wood screw) to replicate the large - flat end

WARNING/SAFETY: be extremely careful when playing around with power supplies from AC adapters. Without Gnd contact, the floating output voltage, although very low between the + and-terminals, can be very high relative to the Gnd. So watch out for good insulation, and no matter what: STAY AWAY FROM WATER !