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Old 04-12-2009, 01:13 PM   #4 (permalink)
EcoModding Apprentice
Join Date: Oct 2008
Location: Chile
Posts: 223

Mercedes 89 D - '89 Mercedes 300 E
90 day: 33.86 mpg (US)

Skodie - '09 Skoda Octavia TDI PD
90 day: 38.84 mpg (US)

1993 Mercedes 300D Turbo - '93 Mercedes Benz 300D Turbo W124
90 day: 26.19 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 9.61 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 33.34 mpg (US)
Thanks: 15
Thanked 9 Times in 7 Posts
mpguino available


I wonder if I can use the mpguino on my car. My car is a modified 1989 MB 300E which now runs on diesel. So, the signals must be created to drive mpguino somehow.

I have been trying to do that, using an Arduino clon with a digital screen. In the lab it works, but I havenīt been successful driving it with real signals of the car.

The signals I plan to use are basically two:

a) The tank level difference between starting time and checking time. Not very precise maybe, but better than run a whole tank trip. This info is analog.

b) The distance in km or miles for the same period, taken from the cluster panel, which has a facility to convert analog km in digital km.

The rest is calculation: marginal yield, mean yield, total distance, fuel left, etc.

For calibrating fuel consumption, I plan to calibrate the tank measuring tank signal and writing it down this way:

1. Empty the tank as much as possible.
2. Fill the tank until reserve light is off. This will tell me how much liters I have as reserve.
3. Fill the tank gallon by gallon and measure the resistance and write it down.
This way I take account of the irregular form of the tank and the non linear fuel indicator in the instruments cluster.
4. Go until the tank is full.

When I connect the cables to Arduino, it gets very hot and I have to shut it off, to avoid its destruction.

Using a pot the board works ok, though. But the tank signal is something as a voltage controlled by the sender resistance, which is a different thing. I donīt know how to polarize this signal to input an analog port on Arduino.

Can you help me?

Thank you much.

Old Beaver
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