The shop I work at uses a lot of e85 flex fuel for racing purposes. The big problem is, here in AZ, flex fuel from the pump can be anywhere from 54% to 85% ethanol. This makes tuning quite a headache, so we test each car we see. I thought it would be a cool idea to build a rig that has a self contained sensor, pump, power supply etc, so we can pour a little sample into it and get a readout.
The problem is, I can't seem to get accurate data to display, even though we've tested the sensor itself and it's working. Right now I'm using Freqmeasure to just try and display the hz that the sensor is outputting. it seems to be low, the test sample was tested at ~55% ethanol (105hz), but the arduino is reading 64hz. We scoped the sensor and confirmed it's outputting 105 - 110 htz consistently.
I'm using the example script that comes with the freqmeasure library with no other changes and using D49 on my ATmega 2560 as instructed.
Please help, I'm clearly a car guy and NOT a programmer...