Programmable deep discharge protection for multiple-cell LiPo accus, open drain output, AVR.

I built a deep-discharge-protector for multiple cell lithium polymer accus with a AVR microcontroller. I started this project when a friend asked me to help him with his 12V-LED-stripes in his kite. He powered them with three LiPo-accus. I used the PCB of a damaged chinese LiPo-warner. The output voltage is regulated by a DC/DC-converter module with common GND, so the open drain output of the deep-discharge-protector can be used for the regulated 12V. The AVR is running with the internal R/C-oscillator divided by 8. I used the PWM output to dim the LEDs or to let them flicker at the first threshold, at the second the output is switched off. The firmware is in Flowcode 5.