For discussion of Speeduino compatible boards designed / built by other members of the forum and for guidance around making such a board
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By exvils
#43169
I just get board delivered. If i update Bom to have same looks/sizing as 0.4.3 and pazzis bom's can you upload it to github? also when i looked in bom's like month ago when i ordered pcb i didnt know what version should i order, as there were multiple sheets -thx
also i still haven recieved 4n35, is possible to use something else? like diode just to get car started?
User avatar
By Raku
#43171
exvils wrote: Wed May 27, 2020 11:47 am I just get board delivered. If i update Bom to have same looks/sizing as 0.4.3 and pazzis bom's can you upload it to github? also when i looked in bom's like month ago when i ordered pcb i didnt know what version should i order, as there were multiple sheets -thx
also i still haven recieved 4n35, is possible to use something else? like diode just to get car started?
i will do that. sorry for the confusion. now bom is fixed. 4n35 is used for the ac idle up control. you can run without it.
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By exvils
#43359
So i redone the BOM, but this would also need another re-do for 4cyl and 6cyl stock setups, as well as for setups with swaped/custom ignition and injection(full bom, but for 4cyl and 6cyl).
I did changed the diodes for same as Pazi88 is using in his setups, same for few other things. I also added a lot of personal notes. (as i find microfit connector expensive/hard to optain, so i added note, that others can just use external 6pin connector with cable.)
i also exported EasyEDA v1.7 schematic to PDF which would also help others if it could be posted on front page, but few things are outdated/not present on mine 1.7 board - so schematic on easyeda need fix before that. Also by looking on schematics - There should be option for VR cam sensors, with trace to already present VR-conditioner
By Rob123456789
#43377
pazi88 wrote: Wed Nov 06, 2019 7:18 am
It also seems that even the 4.7nF cap for C25 isn't small enough for 60-2 trigger wheel. The speeduino 0.4.3 design uses originally 10nF cap, and when calculated with the 1k resistor in the line that should be plenty enough for 60-2 trigger wheel. It works nicely with simulated signal from speedystim for example. But with real trigger wheel and hall sensor, you don't get that nice and even square wave that you get with simulator. And in reality, because there is 1k pull-up to 5v, the voltage to high state goes through 2k ohms worth of resistors. Which makes the signal rise time way too slow and there will be problems from 6000 RPM upwards. So that's why I changed to 4.7nF cap originally. But with high RPM and the trigger wheel vibrating slightly, the pulses from the teeth can still get short enough to cause problems. So after testing with real trigger wheel and hall sensor, I ended up using 1nF cap for C25. That gives nice and robust signal for the mega. I did change that for the BOM files.

I'm getting occasional sync loss at 5000+ rpm. I'm only using a week trigger filter so I'll change it to medium and hopefully that will fix it but would it be a good idea to change C9 capacitor to 4.7nF or 1nF(Same cap as C25 on Pazi88's M52 pcb)?
User avatar
By exvils
#43407
That new cap works great irl.. clean signal at 7400rpm from stock vr sensor
I need help with other thing though - should Dme relay pin 36 have always 12V on it? even with ign off? or should it be switched on with dme relay with ignition?
is this same for other motronic ecu's? (on pin 54 for example in m50 or m52)
By Rob123456789
#43420
exvils wrote: I need help with other thing though - should Dme relay pin 36 have always 12V on it? even with ign off? or should it be switched on with dme relay with ignition?
is this same for other motronic ecu's? (on pin 54 for example in m50 or m52)
Yes it's the same as other motronic, no it doesn't have 12V on it all the time but its is connected to constant 12V through the diode.

I think the way it works is when the ignition gets turned on the DME relay pin (36) get connected to ground and this allows the relay to turn the rest if the car on. When ignition gets tuned off there is still current trying to go through the DME relay circuit as it has inductance in the relay coil, this current can cause a large voltage spike on pin 36. So you use the diode to constant 12V as a safety so that pin 36 can never go over 12V.

Sorry that's probably not explained very well, I'm sure someone else can explain it better. Just connect the diode between pin 36 and 18 and it should be good, it's what I've done and its working. The cathode side with the line on goes to pin 18.
User avatar
By Raku
#44106
guys there was a issue with arrow.com bom part number for Q14 and Q15. it needs npn transistor but bom shows pnp version of the 2n2222.correct part number should be 2N2222 PBFREE and now bom is fixed. lcsc part number is correct.
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