MicroSquirt.com read only forum (Jan.15,2018)

I've just tried the trigger return feature, and have strange numbers in my datalog.

Ignition input is VW 4cyl distributor, trigger offset is 83 degrees btdc. Trigger is the beginning of the 'window' so voltage going low at this point, inverted of course by the optoisolator to give a going high ...

So how I understand it so far, is that the pullup resistor holds the opto+ input high, and the ground holds the opto- low. When the hall sensor passes the window in the dizzy ring, opto+ is pulled down to ground (or near enough). When the window in the dizzy ring has passed the hall sensor, and ...

Wiring in a pullup resistor between Vref and optoin+ to give myself a better square wave, as I tested and wasn't seeing anything. General consensus is that I should use upwards of 5kohm for this purpose, to minimise the current drain on Vref, but does anyone know roughyl how much current the Hall ...

Bah! Now running from hall sensor on dizzy, and still no rpm input showing in megatune. Vref to hall +ive, optoin-/sensor ground to hall -ive, and optoin+ to hall output. This is on the dizzy the car runs on so is fine. Maybe I should be looking at supplying it with 12V then. Will try again tomorrow.

Ok, thanks Rob. I'll have a try with 12V as the supply for the sensor and see what I get. If it doesn't work out I'm going to try the hall sensor on the distributor instead, and go from there, as the crank sensor on the golf is a proper arse to get to (and I'm skint). Cheers.

Hi folks, just wondering if anyone could confirm something for me. I'm using a vw hall crank sensor, with the 60-2 trigger wheel, as a tach input into microsquirt. I'm not getting an RPM input into megatune when I crank the engine over, so I tested the crank sensor.

Basically I connected the ...

So is it safe to use Vref to power a hall sensor, or is this asking too muchof it? Sorry, I have no idea how much a hall sensor uses..