Picture of Power Arduino with a cellphone
Old cellphones are easy to acquire and they have built in lithium charging circuitry. What a wonderful base for a power supply for small mobile things. I hooked up a cellphone to the arduino with the ability to charge the cellphone when you plug the arduino into the usb port. Please note that this was just a quick rig and as i did not have the correct screwdrivers, does not involve taking apart the cellphone. I'm sure if you have access to the correct screwdriver you wouldn't have to cut the cellphone charging connector and could just solder wires directly to the charging terminals. Sorry about the image quality I made it in between college classes and so i took pictures with my laptop's webcam.

You will need:
an arduino
an old cellphone (must use 5volts as its wall wart charging voltage)
some cellphone batteries (optional, minimum one)
wires and a diode
the cellphones wall wart charger
a connector of some sort to plug into the arduino (i cut a chip socket in half for mine.) Minimum of 3 pins
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Step 1: Connecting wires to the battery

Picture of Connecting wires to the battery
Open up the cellphone and remove the battery to reveal the battery connectors. I also removed the SIM card. Examine the battery to figure out what terminal connectors on the cellphone go to the positive and negative terminals on the battery. Solder wires to these terminals. Don't worry about any third terminal, this is just a temperature sensor or something and is for the cellphone to worry about.
Why wouldn't you simply make a battery holder for the cell phone battery?
Modifying a working cell phone seems a bit extreme just so that you can use it's battery pack.
Neocronic2 years ago
That's not a power source, it's a cell phone!
cool..........dats great but i still need some one to pls help with a brief understanding of how the arduino microprocessor works and why do we really use it
ReCreate5 years ago
don't arduino's need at least 5V to operate? The Lithium ion battery Providing only 3.7 Volts...
some arduino mini's operate at 3v3
I did some experimenting, my Freeduino will operate down to about 3 volts. The ATmega chips will actually run at 1.8V. I suspect the limiting factor may be the USB. Another problem at less than 5V is if you're using analog pins, your analog outputs will be off and analog reads won't be as accurate.

You sound correct - but his little LED is blinking...
scottinnh4 years ago
Add a boost circuit (copy the Mintyboost) to raise the 3.7v to 5v...
Absolutely Genius
aderistic5 years ago
that´s was cool
nam.keeheon6 years ago
wow, thats an old phone...
Xumahare6 years ago
You'll have to show me this sometime, zimirken. Just don't ignore me next time you see me, okay?
I am intruiged! You will have to show me this!
Welcome to Instructables!
zimirken (author)  JamesRPatrick6 years ago
Thank You