simple voltmeter with LCD and keys to change resistors
basically a voltage splitter 100k resistore in front of voltage source to measure, connected to A8, and a 10k resistor to the ground.
pin A12 is set to calibrate for 5V if you measure it.
the shield i am using is having keys, select and arrows. with select, you can switch between r1 and r2, and change the settings in 1k steps.
shield used is a LCD Keypad shield