We discover it discouraging when battery operated consumer electronics don’t include a method to link an outside power supply. We try not to purchase disposable alkaline cells if we can prevent it, as well as this dummy battery AC adapter hack will aid in our mission.
The battery compartment shown above is for a motorized infant swing. It accepts C sized batteries (who has those just lying around?) as well as lacks a barrel jack to link a wall wart adapter. [Jason Smith] mentions you can get around this by linking your positive as well as ground wires directly to the conductor springs. however utilizing a dummy battery makes it a bit much easier to eliminate the adapter if you do want to utilize battery power.
Each of the orange dummy is a wooden dowel with a screw at each end. The screws are linked with a piece of jumper wire, shorting the two terminals. This completes the circuit in the battery compartment as well as enables him to power whatever from the adapter cell at the bottom. The adapter utilizes an LM317 adjustable voltage linear regulator. He utilized fixed resistor values to dial in his target voltage. The devices must be rather forgiving as battery voltage starts higher than the printed value as well as drops as the cells are utilized up.
This method has been around for a long time. one of our favorites was a hack that converted an Apple Magic Trackpad to USB power.