Electric string winder for guitar, bass and other string instruments

This is an electric string winder for guitar, bass and other string instruments.
This tool is helpful to replace your instruments strings, of course you have to fine tune by hand.

It is almost all built with broken things that laids around in my garage.

The electric screwdriver has non working batteries and no power supply. I replaced the original battery pack with two Ni-MH 1.2V 3800mAh batteries wired in series.

Then i built a NiMH battery charger and embed the battery charger in the screwdriver box. I've found the battery charger design searching for "Low Cost Universal Battery Charger Schematic". The schematics below is just the schematics proposed by the original author, with values i'm using for my power supply / battery pack.

As old mobile phone power supply, 9.2V 440mA.

Then i've built the guitar peg winder, using a plastic guitar peg winder that as the lever broken, and a screwdriver bits worned-out, i cut the broken tip, and then i fixed it to the guitar peg.

Notes

• read risk disclaimer
• excuse my bad english