Join Date: Mar 2011
Location: Sonoran Desert, Arizona
Fuel Gauge Fixed - It's Now Linear
I never liked that fact that the fuel gauge was so non-linear. To my way of thinking, a measuring device should be reasonably accurate. So, I decided to see if I could make it better.
1. My tank (2011 DL650A) holds a little over 5 1/2 gallons.
2. There are five solid bars on the fuel gauge.
3. Each bar should represent one gallon. As each successive gallon is used, the associated bar turns off.
4. After the fifth gallon is used the bottom bar is no longer solid, but starts flashing indicating reserve.
I decided the project would best be done with a micro-controller. I designed a circuit built around the PIC16F688 and wrote a program to operate it. Essentially, the micro-controller reads the resistance from the sending unit and determines which bars on the gauge to turn on/off.
The micro-controller has the ability to be reprogrammed while it is still installed in the circuit. That enables me to modify the program as necessary and reprogram the micro-controller while it is still on the bike. This was very convenient during development.
Completely plug & play. The fuel tank connector is unplugged and the circuit board is plugged into the two connectors.
The modification works very well, given the constraints of the tank sender. These are twofold. First, the sending unit doesn't start moving until a little over one gallon is used. Secondly, the sender stops moving before the fifth gallon is completely used. This causes the first bar to stay on longer and the last bar to start flashing sooner that I would have liked. Unfortunately, this is unavoidable. Even given those two minor issues, the project was an overwhelming success.