This instructable is for charging a ds lite using an Arduino and two wires. This is also my first instructable, so it may not be as good as possible. :)
NOTICE: I am not responsible for any damage done to your ds, please work carefully and check to make sure all is as supposed to be.
Step 1: What You'll Need
You will need:
An arduino that runs on 5 volts
Two jumper wires
A ds lite
(It will probably work with a regular ds, but I don't have one, so I couldn't test.)
An upload cable for the arduino, or some other power source for your arduino
Step 2: Find Polarity, Find Input Voltage
In this step, we need to find the polarity and the input voltage.
On the bottom of your ds, there will be a bunch of information, including the input voltage. The input voltage is 5.2 volts, so the arduino should charge it just fine.
The other possibly important piece of information is the polarity of the input. After searching google for a while, I finally found this site:
http://surugi.com/projects/DSLiteUSB.html telling how to replace the charge port with a mini usb port. There is a picture telling the polarity there, but for convenience, I have a picture here.
In the picture the ds is upside down, make sure that when you connect the wires they are the same.
Step 3: Connect the Wires
Now connect the wires, plus on the ds to 5v on the Arduino, ground on ds to one of the grounds on the arduino.
Step 4: Charge!
Now, plug the Arduino into your computer or power source, and the orange charge LED on the ds should light up.
Step 5: You're Done!
You're done! I hope this was helpful, please comment if you liked, have any questions, or have any suggestions.
Edit: I tried this on a friend's DS lite, and the hole for the pins were too small, you may have to play around with using different wire sizes.