All boards have a huge bug. The low fuel wire does not get grounded like the oil/neutral lights. Instead, the fuel level sensor is a NTC thermistor and you need something like an 82Ohm/5W resistor to create a voltage divider to read the +12V signal.
This is actually pretty complicated, because the +12V is variable due to motor speed & battery health. Also, it is outside of the spec of the 5V ADC of the micro controller. Need to come up with a circuit/solution which translates & compensates for the above. Also, the software will need to implement hysteresis so that sloshing fuel doesn't turn on the light pre-maturely.
To make matters even worse, the 2007+ models use a completely different circuit then the earlier 2nd gen models.
synfinatic
commented
10 years ago
All boards have a huge bug. The low fuel wire does not get grounded like the oil/neutral lights. Instead, the fuel level sensor is a NTC thermistor and you need something like an 82Ohm/5W resistor to create a voltage divider to read the +12V signal.
This is actually pretty complicated, because the +12V is variable due to motor speed & battery health. Also, it is outside of the spec of the 5V ADC of the micro controller. Need to come up with a circuit/solution which translates & compensates for the above. Also, the software will need to implement hysteresis so that sloshing fuel doesn't turn on the light pre-maturely.
To make matters even worse, the 2007+ models use a completely different circuit then the earlier 2nd gen models.