Building A DIY FreeEMS Hardware Setup

All home-built FreeEMS implementations without a forum of their own, usually TA-based.
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Fred
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Building A DIY FreeEMS Hardware Setup

Post by Fred »

Inspired by MrOnion, I'm posting this short guide to DIY builds!

Stern Warning

Firstly, a stern warning for those bright eyed, bushy tailed people who think doing a DIY build will be fun and easy. You're wrong. It will only be fun. It will not be easy! You will have to search through various schematics making assumptions, having misunderstandings, and consequently doing things wrong. You will have grounding and power issues that cause you to question your very existence. It will be painful, and slow, and annoying, and yet, it'll give you an enormous sense of satisfaction which you'll never forget. If you really want to do a DIY setup, go ahead, but don't say you weren't warned! :-p

CPU Board Options

Secondly, you MUST get yourself a MC9S12XDP512 CPU of some type to use in your DIY build. Don't bother asking about alternative CPUs, most are not suitable, none provide any real world advantage, and all will require more work than you can reasonably manage, to use at all.
IO Design Options

The obvious route is perfboard + through-hole components all hand soldered. This is the DIY spirit that the FreeEMS project was founded with. However thre is another option, thanks to MrOnion: The OnionBoard! See this thread for more info: viewtopic.php?f=77&t=1971

The DIY route is no small task, consider that a typical purpose-built FreeEMS board has a component count up around 200 - 400 parts, and you have some idea how complex your task is. You need to list out your sub-circuits, figure out what each needs in terms of parts, space, and connections, figure out how to lay them out on a piece of perf board, decide on protected/unprotected operation, etc. This will take a LOT of time even if you're careless about the process.

Previous Implementations

An overview album is available on facebook, however most builds have a thread on the forum too, I'll try to keep an index of them here:
  1. My original Volvo DIY build, no thread, see various pictures around the web. Ultra simple, basic 5V supply, 1 FET, min sensors/conditioning.
  2. Various Hotel Hyundai DIY builds: viewtopic.php?f=62&t=1427
  3. Peter's truck DIY build viewtopic.php?f=55&t=1787
  4. Peter's Honda DIY build viewtopic.php?f=62&t=1533
  5. Sim's various DIY builds viewtopic.php?f=62&t=1263
  6. Sean's old LT1 DIY build viewtopic.php?f=55&t=1146
  7. em_knaps's Slater DIY build viewtopic.php?f=62&t=1336
  8. em_knaps's Volverc DIY build viewtopic.php?f=55&t=2224
  9. Aitor's Ford Sierra DIY build viewtopic.php?f=62&t=2193
  10. Via's Supra ECU build viewtopic.php?f=62&t=2367
  11. Noah's HUGE DIY build UNUSED viewtopic.php?f=62&t=1650
  12. Mike's Cube ECU DIY build UNUSED viewtopic.php?f=62&t=1915
  13. Matthijs' French DIY build UNUSED viewtopic.php?f=62&t=2268
Missed yours? Let me know by posting up here with a link to your ECU build thread! :-)

Any of these people will tell you that doing a DIY build is a hard road, but that you'll learn a lot. Sadly, that learning often comes at the cost of other people's time as well as your own. I recommend you get whatever the current flavour of the month board is, instead, right now, a Jaguar from Andy. But if you're stubborn, go ahead, put a smile on my face, and the faces of others, and make something imaginative to run your engine with.

Welcome to FreeEMS, your freedom to create is welcome here! ;-)

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
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