I have a debounce question. With the latest version of the MPGuino, what is the preferred method to debounce a geo metro? If the double resistor method is not working well, should we consider using a capacitor instead of a resistor between ground and VSS? (see below)
What follows is what I've tried with my '96 geo metro 1.0L. For reference, I just got my MPGuino, so it is version 1.7 or something. I tapped into INJ underneath the airfilter, like someone has posted pictures of, for their '98 Metro. For VSS I went behind the glove box.
Without any debounce resistors, instant speed was bouncing around pretty bad while driving 30 MPH and up.
I tried adding a 1k resistor from ground to VSS (no additional resistors) and it wasn't getting any VSS reading at all.
I tried switching to a 10k resistor from ground to VSS and it worked again, with somewhat less bouncing.
Right now I'm doing 5.6k between VSS and Ground, and 5.6k between VSS and switched 12V. It still bounces some while driving 40MPH+.
The MPGuino is a great little device! It would be great to have a more definitive way to debounce the Metro VSS for it. More resistance? Less resistance? Keep the Ground and 12V resistance equal? etc.
Has anyone tried a Metro VSS debounce circuit with a capacitor?
It is explained at
ikalogic.com/debouncing.php
If I understand the schematic right, for this design you would keep a resister between 12V and VSS, but instead of a resistor between VSS and ground, you'd use a 100nf ceramic capacitor. Any reason to not try this? Could it fry the VSS unit?
