Based on an atmega328P, the goal of the board is to display the difference in voltage of each cells with the average of all the battery cells.
A 12bit ADC is used to measure precisely the voltage of my four three cells batteries from Turnigy. The oled display is turned on when the user push a button. The OLED display shows through a bargraph the difference of each cells with the average of all the cells. It will not balance, but it will show to the user if there is a problem with a cell.
Also, if the "dispaly button" is held more than 3 sec, the board enter in "security mode", then if the bike moves, a lovely song will be played by a 130dB alarm.
All of this will consume around 1mA (and I aim for less) and will be powered by a single cell Li-Ion battery 18650 Panasonic. No need to let the big battery in the bike, the security works always.
When the Li-ion cell is discharged, the OLED display shows a warning message
The size of the PCB is 100mm x 42mm, because I can, and because I can put it directy on "the big battery" without searching for a place that doesn't exist in my E-bike.
If you want to build this, you will need :
- A rape alarm from Amazon, they're really loud and small, consumme around 100mA on. (those all rounded with different colors, around $10)
- A vibration sensor SW420, seems to works well
- All the components listed in the "design" section
- The code (work in progress)
- A soldering iron and a bit of skill
Oh, and btw, to unlock th bike, you will need a magnet :) -> hall sensor
EDIT : well... After the first board didn't worked (ADCs diying when plugging a batterie...) I gave up. Feel free to inspire yourself from that loss of time...