DIYEFI.org Forum

So, you've decided to make your own hardware to run FreeEMS.

Ok, good for you! Now, hands on:

Take one of the hardware projects readily available, like Jared's FreeEMS_1.0, or Marcos's Puma. They are available at
https://github.com/jharvey/FreeEMS_1.0_hardware
and
https://github.com/nitrousnrg/puma

Please, try to use a proper git version control. If you do it, every change can be tracked, and btw, it will be your automatic backup tool ;-) Plus, you will be forking from a working board, and others could create forks from yours, just like in software.

Those repositories contain the kicad (http://kicad.sourceforge.net/wiki/index.php/Main_Page) project for the board.

Take the schematic, modify it as much as you want, take the pcb and modify or redesign it too.

This is a good time to share your progress in this forum (if you didn't do it already!). Sharing allows a much better project integration, and you could get the help from all of us who are already involved with the freeems hardware specification.

Rename the project, there is a thread discussing the naming (viewtopic.php?f=41&t=746&hilit=project+naming)

To rename it you only need to change kicads files, git config, and github config (in case you use github)
For example, if you took the puma board,
* change the kicad files named puma (puma.pro, puma.brd, puma.sch, etc, etc).
* go to https://github.com/*your_user*/puma/admin and change your board name
* modify your git config file, located at .git/config in such a way it points to your repo instead of the original one.

And keep in mind these designs are licensed under the TAPR (http://www.tapr.org/ohl.html) hardware license, so you have to comply with its terms. Nothing crazy, just keep the original documentation you had at the beginning of your modifications, and please allow others to see/use/modify your work for their own interests :-)

Before you start something from scratch, speak up. Maybe there is someone with your same interests, or even a hw deloper like me could modify its own board design to implement some of your ideas.

And as final thought: read, read, read!. There is plenty of information in the forum and its members to create fantastic pieces of hardware :-)

Stickied! Great work, Marcos! :-)

Let's hope it catches on, eventually :-)

At least we're opening a starting point for everyone.

Is there a schematic (PDF) for the "basic" computer anywhere? I'm not a Kicad user but if the schematic is available I can whip it into a FreePCB layout. I could probably manage to deal with a TinyCAD schematic which can export things to FreePCB.

Also from the looking around, is there a reason people are still using RS232 and not going to a USB to serial connection? I haven't looked at the chips in use but I assume you are doing an RS232 to TTL conversion in there and it just seems like sticking an FTDI USB to TTL serial chip and a few passives on the board would be a good idea.

In addition to the schematics is there a specific device size that is being targeted? I saw that one of the referenced projects had a DB25 connector on the end which would make it about 2 x 3 inches.

My immediate goal is a system that uses most of the stock parts on a Buell motorcycle with the addition of MAP and a heated wideband O2, it currently uses speed/density and a narrow band O2 for adjustments to the AFV during the limited range that the narrow band will work. Ignition is by a cam sensor, not sure of the pulses yet, with RPM and throttle position related timing maps. Since it is a V twin they run the front cylinder on a different map from the rear to keep the temperatures in check. It also has a cooling fan in some way triggered off of cylinder head temp and controlled through the computer.

You can get the schems out of kicard, or various pdfs that are around, you may want to tweak them, though.

232 coms on the TA card, no reason to dothat if you're designing from scratch. Do just as you say and use the ftdi chip. Marcos' design has that.

Fred.

Look for FreeEMS 1.0 for the defacto standard design. Which has never been built, and is intended to be the most flexible. Also look for the PUMA version, a spin off of the defacto standard, which we are having spin 1 proto'ed now. This is the first spin of this board, and it will likely have problems of some sort, but it's more refined than the 1.0.

1.0 uses the TA card as the brain, this takes care of may soldering requirements, and initial firmware programming requirements. It then uses a stack of cards, to interface the brain to the engine. The first card in the stack is 1.0 which has the bare min for running an engine. The second card (which would be called 2.0) is planned to include more advanced features like a knock sensor, IAC, and other really handy circuits. The third card (which would be called 3.0) is planned to include advanced features like ion sensing, ect. The bottom of the stack is the interface card which interfaces to an OEM connector, or what ever you have.

Check out FreeEMS.org and look for the wiki. Hmmm, we should get around to putting PUMA on the wiki.

PUMA is intended to be a specific build. It's not as flexible as the 1.0 stack. It's mostly SMT. Spin1 is scheduled to be ordered today, which has one key unknown. The CPU pin out. This is the first time an attempt has been made to assign a pin to a function. While we believe we have made good prediction, we may curse and swear when we get the first boards. Other than that, it probably has most of the features one would want on a typical engine setup.

In many cases the 232 will fulfill a wide temperature range, while USB (and eth) is typically designed for room temperature environments. I think that's one reason why we often see the 232 still kicking around. PUMA uses an USB FTDI chip, but that chip won't work for unless it's room temp, however you probably won't be programming it unless it's warm. Other than that PUMA should hold a large temperature range.

Also look into KICAD. Once you do, I'd bet you will be left wondering why FreePCB still exists. I'm a big fan of KICAD, It's easy to use, flexible, free (as in beer and freedom) multi-platform, ect.

You could copy either PUMA or 1.0 for a motorcycle design. I'd have to know more about your desired circuits before I could recommend one or the other.

Also have you found MultiMAP?

Oh yeah and welcome along.

Hi Guys (Hey Fred, "Huff" is here!),

Just wanted to second a request that was earlier posted about hardware design documentation. I really don't want to install KiCad just to be able to view the schematics that you have created. Would it be possible to include pdf versions of the schematics (and other "living" documents) in some easy to remember, "fixed" location.

I did find "freeEMS_1_combined-full_A.20.pdf" at the "https://github.com/jharvey/FreeEMS_1.0_hardware" link, but the sheets are dated November, 2008 (is this the latest version?). I also located "Puma_spin1_SCH_10-12-26.pdf", but it was not to be found at "https://github.com/nitrousnrg/puma" but was located in a link on a different thread (thank you jharvey).

Just saying that it would be nice to have a single location that contained only maintained copies of the latest documentation (schematics, BOMs, standards, ....) in common file formats.

Thanks

http://puma.freeems.org

sorry for the extra stuff that lives on that page, though. Will be removed soon. (as soon as Fred gives me ssh access to it!)

Welcome Huff! :-)

Marcos, spam me with tgzs in my email until I do and I'll keep it up to date.

Fred.

It appears the copy on puma.freeems.org are the same files I posted in the forum thread. I just created and sent nitrousnrg updated PDF's. I'm sure he'll get them into the puma web page shortly. Look for the ones with the date in the file name. The changes aren't all that big, but there are some changes.