Computer - 2019

Computer problems are:
  1. Fuel gauges not working correctly.
  2. Charging system indicates negative.
  3. RPM inoperative.

You can see the fuel sender float at the bottom of the tank. This float is tied to a variable resistor which is supposed to indicate the fuel level.

But when 20 gallons are in the tank it indicates 2 gallons, so this type is of sensor is no good for this type of tank.

No matter how many changes I can do in the Arduino programming it doesn't work properly.

I will need to know exactly how much fuel I have on board, so a new design has to implemented. and the Arduino re-programmed.

My friend Fred and I were noodling on how to build a great fuel sensor.

We thought of using light in a dark tube connected to a photo cell that would read out the fuel level due to the amount of light the fuel blocked. We decided against this idea because we never know how opaque the fuel will be on different fill ups.

Then we thought of using probes installed on a tube and measure the resistance of the fuel at different levels. Diesel oil is required to be non-conductive, so this idea went by the way of the buffalo.

Then we thought of using a float with a magnet in it that travels up and down a tube. Inside the sealed tube are reed switches connected across a resistor grid, that close when a magnetic field is present. Each reed switch that closes sends a different voltage level to the Arduino.

Shown above is a commercial unit I found, but none of them are long enough, nor will they allow me to put the reed switches at the appropriate levels in the tube.

So it's going to be an Arizona winter project.

   
Charging is showing minus instead of plus. Here is a picture of the ammeter sensor installed. Current flow comes from the diode splitter shown on the left. Here is the data sheet.. Oops, looks like I installed it backwards. A simple fix.. Yeah !!!
   
 
Here it is installed what you would normally call the "right way".  
   
RPM not working. This is a picture of the Inductive Proximity Sensor and the bracket that is supposed to send a pulse to the Arduino on each revolution on the engine. It is currently set at ? mm. The specs indicate that it works from 6-32 VDC at 4mm, and I have it wired to 6 VDC.
I hooked the computer to the ECU so I could monitor the RPM. So with a piece of metal I simulated the engine turning by tapping the sensor. RPM reading was right on. Must have fixed it during the winter when I checked the ECU tester.
Yeah it works !		 Here is a close up of the sensor and adjustment bracket I made. The led on the back of the sensor is supposed to light when it detects something. So it should pulse when the engine is running. Right now it is lit all the time, so it is working because the metal bar is right over it.
I set the gap to exactly 2mm.