[DStage]

Hi there. I've just aploaded a new ETC variant called DStage_ETC_DSv1.0 where "DS" stands for (no, not DStage, I'm not that narcissistic to put the name twice in a row ) "DSpeed". And DSpeed is my variant of Speeduino for which this one is dedicated for. More on that in this topic: viewtopic.php?t=6582

The idea is to swap the stepper motor driver with ETC module and use the connections of the former for ETC signals purposes. In theory it could be used on any Speeduino with DRV8825 or equivalent stepper driver, of course as long as it fits physically/mechanically.

ETC DSv1.0 is largely based on ETC v2.2. Main difference is the H-bridge. On all other ETC variants the H-bridge was build using discrete transistors and their drivers. Here due to lack of PCB space I've decided to use an integrated H-bridge chip. There aren't that many great options out there especially when ease of availability and lack of space is a constrain. This one has much worse Rdson compared to nice individual MOSFETs so I hope it won't cook itself and its surroundings. Time will tell.

Also no idea if there won't be other problems like noise from ignition transistors underneath the board or internal noise due to lest restrictive layout (on the original ETC I was really cautious, here I had to let go a bit). This H-bridge also requires much lower PWM frequency so let's hope the regulation will be still fine.

Speaking of the PWM I had to feed it not to PWM input of the bridge but rather to the DIR pin and datasheet is silent about the maximum frequency on that pin. SO really, it's quite an experiment

I did manage to squeeze in dedicated 5V regulator even though 5V is available on stepper driver socket. However, I wanted to avoid potential noise coming from the ECU on 5V rail and vice-versa, avoid injecting noise that way to the main part of Speeduino and affecting analogue or frequency inputs. It also helps to spread the heat dissipation of the system over larger area and doesn't strain the main 5V regulator.

There's also no Arduino Nano module but user can connect it with 2 wires to some of the pins of main Arduino and use Speeduino SW to create gas pedal map like one of the colleagues already showed in the past.

Anyway, prototype has to be made and tried out to clear out the doubts.
Here are the production files for anyone that wishes to try: https://github.com/DStageGarage/Electro ... n/ETC%20DS

[PedroV9]

I really like the work you've done, and I really appreciate you sharing it!

The place where I live lacks more advanced electronic components, and I want to adapt the project to use components that I can find more easily. I'm thinking of replacing the MCP6L04 with an LM324. I know it's a much older OpAmp, with higher noise and power consumption, but could the replacement be viable? And also using an H-bridge with IRLZ44N and IRF4905 MOSFETs.

[DStage]

LM324 can work from ground at input but it's not a rail-to-rail op-amp therefore it will saturate around 3,5-3,8V maybe slightly more if you're lucky at the output/input with 5V supply and the whole thing won't work. You would have to find something that is rail-to-rail or modify the power supply and adjust resistors for reference voltages.
MOSFETs can be swapped easier for anything that has low enough channel resistance that it won't cook itself and the board with it.
But why bother modifying it when you can order it already assembled?

[PedroV9]

LM324 can work from ground at input but it's not a rail-to-rail op-amp therefore it will saturate around 3,5-3,8V maybe slightly more if you're lucky at the output/input with 5V supply and the whole thing won't work. You would have to find something that is rail-to-rail or modify the power supply and adjust resistors for reference voltages.
MOSFETs can be swapped easier for anything that has low enough channel resistance that it won't cook itself and the board with it.
But why bother modifying it when you can order it already assembled?

I hadn’t noticed that the LM324 is not rail-to-rail. Maybe a 7809 dedicated solely to powering the OpAmps...

I want to replace the components with 100% basic components from JLCPCB or components that I can easily buy in my country to assemble manually. Unfortunately, where I live, import taxes are extremely high, and the dollar is expensive compared to our currency.

[DStage]

I hadn’t noticed that the LM324 is not rail-to-rail. Maybe a 7809 dedicated solely to powering the OpAmps...

We are talking about v1.3, right? Well, what can I say... you can try I don't see a point to make layout modifications or some bodge wires so I would just change U4 to 7809. If you modify the calibration procedure accordingly to 80% higher voltages it's even possible you won't have to touch neither the R14/15/16 divider nor the IAC R24/26/27 resistors (although you might want to lower the maximum IAC opening and therefore change those values anyway). Everything else I thing is from the list of basic components...

I want to replace the components with 100% basic components from JLCPCB or components that I can easily buy in my country to assemble manually. Unfortunately, where I live, import taxes are extremely high, and the dollar is expensive compared to our currency.

With one extended component (opamp) the difference is a little over 3$ (MCP6004/6L04 is a lite more expensive itself than LM324). I guess it can make a bit of a difference. on 0ne board but on 5? Don't get me wrong, dollar is not particularly cheap here either
However you may find it hard to replace U5 I think. Maybe you would have to give up part of the fail safe mechanism and not populate this one. That is without redesign of course. On v2.2 all op-amps are in SO16 but there are different MOSFET drivers so again not everything from basic list.
I can't remember (would have to check) what else was from etended list but maybe C13 and something else..