AA battery to USB adapter

Replace regular AA battery with USB powered one. You can set the voltage for 1/2/3xAA battery replacement.

Required tools:
- mini DC-DC step down converter (11x17mm or smaller)
https://www.aliexpress.com/item/4000938525410.html?spm=a2g0o.productlist.main.5.789ckc51kc51Ig&algo_pvid=a9838bfa-ce18-4c67-84f6-5aed02134cc2&algo_exp_id=a9838bfa-ce18-4c67-84f6-5aed02134cc2-2&pdp_npi=4%40dis%21USD%215.33%213.57%21%21%215.33%213.57%21%402101ef5e17051580594381509eef84%2110000011322538105%21sea%21HU%21137414099%21&curPageLogUid=5gwXJyDe0dRH&utparam-url=scene%3Asearch%7Cquery_from%3A
- 2 pcs 3,5x15mm self tapping screw
- USB A cable
- some cable and soldering iron

1. Solder the USB cable +/- to the input of the DC converter
2. Solder some wire to the output of the DC converter
3. place the cable next to the screw (pay attention to the polarity!)
4. Set the output voltage. 1xAA 1.5V, 2xAA 3V, 3xAA 4.5V