Thanks romP44, so because of the HV Zener we get such a reduced duty cycle and can run 271mA, makes sense.romP44 wrote: ↑Fri Aug 07, 2020 10:12 amIf you have max coil primary voltage at 400V :
- 1N4004 forward voltage: 1.1V
- Zener voltage: 100V
- Opto forward voltage: 1.3V
=> 400-1.1-100-1.3 = 297.6V
I = U/R = 297.6/1100 = 0.271A => 271mA
Max current for 4n35 is 1A for t <10 μs. So it should be fine.
But I have no idea about peak voltage duration...
Continuous max forward current of 4n35 is 50mA.
Good to know! My input LED will suffice for me, but maybe if I make few more boards I will add output indicator.PSIG wrote: I have diagnostic LEDs on my board designs, and they are surprisingly useful at higher speeds or tooth-counts. While you can't see individual flashes except at cranking and perhaps idle (even a 60-2 wheel is a blur at cranking), the eye can notice skipped or long pulses and other anomalies. Note the diag LEDs on boards such as the MiniMAX-A2 and DSC are on the output side, so indications are not of input signal activity, but conditioner output results (what Speeduino should see).
I wonder how hard It would be to make an Indicator LED blink on every 2nd / 3rd /4th pulse. divide the coil pulses.
I would like to report my setup has been working great,
no false triggering with the 100V Zener that I can see.
I copy pasted some 'moving average window' code just to get it up and running,
still going to rewrite the code to try get it a little more responsive.
even though its close to perfect.
when I'm done I'll pastebin the code if anyone is interested.
Here are some janky vids.
First video my multiplier was not correct, displaying 1/2 my RPM.