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Cinchdogs LSx board design...... 
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QFP80 - Contributor

Joined: Wed Oct 01, 2014 7:06 am
Posts: 39
Hi all, I am new to this forum and still trying to play catch up on the progress of free ems. Since hardware design is where i feel i can contribute the most, i thought this thread the best place to start.

I have designed and built quite a few Custom PCB boards, ranging from Audio amplifiers to specialized industrial instrumentation to, gasp, custom one off MS type boards.
Most have worked just fine, some suffered design flaws and were well learned lessons on what not to do :) .

I have looked at some of the proposed/developed I/O boards and Karri's Wildcat would seem to be the closest to what I would like to do, however I want to design a board that goes a bit further.

What i am thinking is an upscale version of a board that i am currently working on, that uses "another" micro controller, however that chip has limited I/O pins and is limited to 4 injector drivers and 4 Spark signals with only a couple extra I/O.

What it does have is a very small footprint and a water proof automotive connector, look up JAE MX23A34, its a readily available and a fairly cheep, compact connector.

What the free EMS might allow me to do, is to expand on my current design to allow 8 injector driver and 8 spark outputs, as well as a host of spare I/O pins for general purpose.

It would probably not be a "do all", as the MX23 series connectors are only rated a 3amps per pin, direct coil control would probably lead to failures, and low Z injectors might also overload the pins. That is not to say that using multiple pins to carry the load is out of the question, MS has used that scheme and it appears to work fine for them. In any case, this was the reason behind the proposed name, the LSx uses modern injectors with high impedance, and utilizes coil packs with built in drivers, so this board would be a good fit for such an instillation. Plus, I think keeping the high voltage stuff near the coils and away from signal lines is always a good idea.

But the idea behind this is very much in line with the Modice style enclosure, mainly something that will be waterproof and small. I like the idea of mounting the ECM under the hood ( in a smart location of course ) and not having to run the entire wiring harness through the firewall. The draw back to this is it does require higher temp rated components, but that isn't a huge issue.

The board I am currently working on that uses the other micro is very compact, about 65mm x 40mm and will use a custom machined aluminum case mated to the ground plane to act as a heat sink. I resigned to designing this after a few failed attempts to put an MS based system on my motorcycle, that has almost no room for anything bigger. I did get it running, but even with an uncased microsquirt module and a DIY JAW, it was a sloppy install and no case for the MS module was a fatal flaw. I played with it for a few weeks but pulled it off because it was mot a question of if, but when it would leave me stranded.

Still some testing to do on a prototype board, and i am sure i will need to tweak a few things, but i see no real reason that this couldn't be scaled up a bit and use the larger micro and a second connector.


Wed Oct 01, 2014 8:26 am
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Cool! :-)

You'll have to use some shoddy low-quality firmware to run more than 6 channels at the moment, though. The dude that implemented it was asked for years on end to improve the quality and always felt it was good enough. He was very wrong. I'll prove that at some point with a properly engineered implementation, however it's not a priority. FreeEMS's Achilles heel is not the lack of timed outputs! It's something else entirely. Something a proper software artisan like myself is easily capable of, and mere hackers have no idea how to produce. All in good time!

Keep in mind that we do not have nor want actual users at this point, only people who are willing to compromise their standards to run *something* and help test it and assist in development of it. Hardware is the easy part, and already in excess supply from various designers. Everyone wants to design some hardware, and good on them, but it's not really helping the project move forward unless it offers firmware development assistance.

Excuse the rough intro! No time to mince words. Gotta pack my bags and get to bed. Big few days ahead, again.

Fred.

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Thu Oct 02, 2014 8:38 am
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QFP80 - Contributor

Joined: Wed Oct 01, 2014 7:06 am
Posts: 39
Fully understand about the need for firmware developers rather than hardware. I am no programmer, that is for sure, but I do dabble in it some, most of my tinkering has been done with (what I'm learning) is the woefully slow and cumbersome Arduino platform. I can do all kinds of neat things with it, but I'm learning that to make things that preform the way I want and are efficient, I'm more and more using better and faster hardware and leaning more to Real C coding rather than pre-coded functions such as "digital write". The "Mega veiw" I have planned for my current board will use a teensy 3.1 and a 128x64 OLED, I can do an entire screen write in ~4mS with the teensy, that's 4 times faster than I was able to achieve with the 32 bit arduino board and ~20 times faster than I could get from a standard 8bit arduino.

Digikey order arrived today, I will start testing the board as time permits. But as this is not a FreeEms implementation I will try to refrain from posting about it other that what Issues I may find in specific components or board layout. I am excited to see what will happen with it though.

One place the MS was and is very lacking is a proper case and connector, the offerings they have that do have a propper connector and case are not any different than any other commercial offering. So I think that if FreeEms is going to appeal to more people, there should be some form factor(s) available that adress what was, to me anyway, one of the big let downs of MS, the crappy case and connector. The Modice addresses this nicely, but is a bit clunky and not terribly cheap.


Thu Oct 02, 2014 8:03 pm
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I totally agree that pretty fully-featured hardware will be like a shiny piece of plastic to a magpie, and that's the issue. That won't move the project forward, it'll stagnate it in the worst possible way. There's only one thing that's going to move this project forward in real and meaningful way, and I'm working hard on it, I promise.

By all means, post about your MS-related stuff, just not in FreeEMS sections. There are appropriate places to do that :-)

Fred.

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DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Fri Oct 03, 2014 11:48 pm
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