It's an age-old question: Is this battery dead? Sometimes it can be a real drag, and you would hate to throw out a perfectly good battery. Alas, you can worry no more! Today we'll create a simple project that will be able to tell us if a battery is properly charged or not!

Step 1: Supplies

We'll be creating a fairly basic circuit here, nothing too complicated. Hopefully these are all things most introductory kits would have on hand.

LinkIT ONE
560 ohm resistors (3x)
Green LED
Blue LED (OK, this should really be Yellow, but my last yellow one burnt out!)
Red LED
Breadboard
Some Jumper Wires

Step 2: Create the Circuit

Relatively basic circuit here, nothing a beginner shouldn't be able to create. The key here is to leave two jumper cables hanging off. We will do this so that we can put whatever size battery we want in between. Simply touching the ends of the jumper wires to our battery will complete our circuit, and give us a battery reading.

Follow the diagram above to create the circuit, then move on to the next step.

Step 3: Deploying the Code

Our code mostly is composed of 3 if statements. We read the voltage from the battery and...

If it is greater than 1.6 volts, we say the battery is fully charged (GREEN LED)

If it is less then 1.6 but greater than 1.4 volts, we say it still has some juice left in it (BLUE LED)

And if we see less than 1.4 volts, we say it is dead (RED LED)

Go ahead and download the code attached and deploy it to your LinkIT ONE to complete the project.

BatteryTester.ino
Download

Step 4: Test Those Batteries!

And there you have it! A fully functional battery tester! Now you don't have to worry and stress about throwing away perfectly good Batteries! Just throw them in your brand new battery charger and you're all good to go!