This is a mini variable power supply that you can power with a laptop power supply. All you need are these components: https://www.amazon.com/UCTRONICS-Numerical-Stabilized-Converter-Adjustable/dp/B01LWXAC5E I used a 19v laptop power supply that was lying around so I'm not sure of the exact model/component type, and the female connector that is inside the box was from an old laptop. All I know is the outer diameter of the jack is ~7.5mm and the inner diameter is ~5mm. If you don't have these here is the file and anybody is free to remix it, not that I can control it I don't think.

EDIT: I have found the barrel jack part, and I have added an improved version. The first version (in copper) had too many gaps and the columns on the side broke away super easily. The newer one (in black), should not break as easily, if at all.

Female barrel jack: https://www.digikey.com/en/products/detail/cui-devices/PJ-096H/9830159?s=N4IgjCBcoEwJxVAYygMwIYBsDOBTANCAPZQDaIAzACwBsVcA7CALqEAOALlCAMocBOASwB2AcxABfQmDgBWKohApIGHAWJkQVWTR0LWITtz5CxkiRKA