Guys,

I want to share my experiment with voltage divider, ADC and AVR
It's pretty simple the sensor are only two resistors and zener diode with capasitor, I don't buy them, I've found it in my box.
We can use it for monitoring our car battery voltage.

## Step 1: The Part I Used

1.ATMEGA128
2.10K and 56K resistors as a voltage divider
3. 5V1 Zener diode
4.  1uF Caps,
5. 16x2 LCD
6.    3 wires to connect the sensor into ADC

Let's continue to the code

## Step 2: The Code and Atmel Studio

Guys, the main key for this experiment is ADC and calculation,
you can calibrate first with 5V from 7805

This is the equation I used

## Step 3: Let's Enjoy My Home Made Battery Monitor

Let's enjoy my home made battery monitor
Also remember folks: by default the avr's (at least in the arduinos) use the 5V line as a reference for the ADC (0V = 0, 5V = 1023), but if your 5V is not too good or stable (e.g., using batteries directly hooked to the AVR not through a regulator) you can also use the INTERNAL BANDGAP REFERENCE (I believe it is 1.1 V).