How to make very easily an USB power adaptor


What you will need:

* Patient to read my weak English (Sorry!)
* 4x rechargable(!) AA batteries
* 1x battery holder with a switch
* 1x (half) data cable
* 1x (half) USB extender cable
* Some glue
* 1x Optional led

I found USB power mods here and around the web with a 9V battery and voltage regulators. With this mod you just need to put colour to colour, that's all. Tha main idea is that the rechargable batteries gives 1,2V (instead of 1,5 like alkaline batteries). 4x1,2V = 4,8V which is close enough to 5V. But my batteries together give 5,1V which is even better. NOTE: Alkaline batteries give ~6V - this could kill your devices!

The first thing you have to do is to find a battery holder for four AA batteries with a switch. We need the switch because these holders have enough space to hide the wires.


Open the holder and remove the cover inside (which covers the switch). Cut the built in wires so they end inside the holder somewhere. Than also cut a data cable (we need the end with the mini USB connector) and the usb extender cable (we need the end with the USB socket).


Make the original hole (where the black ad red cables were) a little bigger so your cable will fit in it, and make an other hole on the side of the holder for the other cable. If you want a led on your box, make a hole for it as well.
Stitch the cables through the holes so a short piece of the wires (the coloured small wires) are inside and the grey/white sealing finishes in the hole. Now you need to use a strong glue to fix the cables.

When they are fixed you just have to put colour to colour and twist the cables. Don't forget that we have 3 red and 3 black cables! Also connect the led to the black or the red wires.
You have to make sure the cables won't connect to each other. I used hot glue pistol for this which isolates the cables and also fixes them.


When you are done, put the cover back, install the charged batteries and enjoy !

Larger images: http://picasaweb.google.com/szucsati/Nokia770

Many thanks for this.

In the US, RadioShack has those AA cases. I use one as a battery extender/emergency charger for N770/N800 and other devices (iPod, etc) which can charge from a USB port. For the N770 & 800, you simply solder a nokia tip to half of a standard USB cable, and you're good to go. I get about 20+ hours or about 3-4 full recharges out of a set of NiMH batteries.

By the way, I saw something similar at Wal-Mart, for about $10. It's just a pack for 4AA's with a USB socket on it. But, would any of us be buying Internet Tablets if we didn't like to tinker ourselves!?

Where would one get just the nokia tip for this project?

I got mine off a 3rd-party Nokia car charger. There are other sources on the Internet, but RadioShack doesn't carry them. Try ebay for the "old to new" Nokia charger adapters - I don't remember a number, or the exact sizes of the tips, both have been documented other places on these forums.