Hello all! Happy Holidays!
I recently made the embarrassing mistake of misreading my fuel gauge, and ran my tank empty. Luckily the engine died just as a reached home, so it wasn't a big deal.
That got me thinking, what would it take to make a low fuel warning lamp? Since the fuel level sensor is just a variable resistor, and the fuel gauge a ohmmeter, I figured I could put a small bulb in series with the gauge just before its grounded. When the fuel is near empty, the low resistance will allow the light bulb to light up, and it should die out once there is enough fuel to make the resistance high.
The question though would be how much resistance of the light bulb would affect the reading of the fuel gauge. Perhaps a small relay should be used instead?
On another note, the engine coolant temperature sensor is just a thermistor, so any ideas on how to implement a warning lamp for that?