This project will utilize the Arduino micro controller, led lights, resistors, a diode and the breadboard to create a system that would be able to test a battery’s charge when connected to a battery.

What you will need:

- Arduino Uno

- Breadboard

- 3 LED's

- 3 100 Ohm resistors

- 1 2K Ohm resistor

- 1 Diode Rectifier

- Wires

Step 1: Connect LED's

Insert 3 LED's into the breadboard. These LED's will be used to display the amount of charge remaining on the battery, with each LED signifying a different level of charge. Red will signify that the battery is low/dead, Yellow will signify that the battery has roughly half charge or so remaining, and Green will signify a battery with full charge.

- Red LED to Digital 4

- Yellow LED to Digital 3

- Green LED to Digital 2

Step 2: Add Diode and Battery Wires

1. Insert a Diode Rectifier into the breadboard (be sure that the white line on the diode is facing the direction of the Arduino).

2. Insert a 2K resistor alongside it and then wire it to Analog A0.

3. Insert another wire on the opposite side of the Diode. This wire will be used to connect to the positive end of the battery.

4. Insert a wire into the ground rail. This wire will be used to connect to the negative end of the battery.

Step 3: Connect a Battery

Simply attach the ground wire to the negative end of the battery and the diode wire to the positive end. The correct LED should then light up based on the amount of charge left in the battery.