FreeEMS design guideline

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Fred
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Re: FreeEMS design guideline

Post by Fred »

Tony, Odd ball is the original Turbo FE3 engine in a truck guy. He's the one that inspired me to go from "no idea about boost and ecus" to "boost and ecu eeeelite" ;-) IE, I saw his truck and started researching stuff years ago. Before that I didn't have much of a clue about anything. So, if he can be looked after, we should :-)

Odd ball, I didn't know you were into your electronics? Great to see you posting! :-)

Fred.
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OddBallRacing
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Re: FreeEMS design guideline

Post by OddBallRacing »

Fred always makes me blush!

I thought about MegaSquirt years ago. I bought a kit and a test board and a relay board and like 5 DIY-WBO2 kits! LOL I'd never soldered a single circuit in my life before!

I have a friend who, on the other hand, is VERY into such things and I watched as he built all the components. I gave him all of the items for his studies in hopes of some progression but his circumstances have not allowed any progress as of yet.

I bought a Wolf3D and struggled with that and Danny (the guy who was the first FE3 in a Miata) was using the TECII at the time and talked me into getting one of those for my truck.

After sending it back to Electromotive to be serviced 3x now it's still hassling me and I'm pondering yet ANOTHER ecu for the truck! But, that's another story!

As part of my total re-wiring of the truck I came up with a relay board idea in my mind as part of the power distribution system I wanted to use in the truck. I created one on a project board and it all worked great; untill I tried to pot it. The potting material, while very thick when I mixed it up, seeped into EVERY nook and cranny, sealing in every fuse and relay, entombing the whole board. That would have been great, until I blew a fuse or relay!

I'm using something else now but it's not serving my purposes satisfactorly(sp) so I will have to make another relay board at some point.

I've got to solve my ECU woes first! One can only check and double/triple check ones wiring and circuits and what not before the ECU is left as the prime suspect for said woes!

Feel free to split/censor this thread, Fred, so as to not let my ramblings de-rail it! I'm watching here more than posting but I *AM* watching!

Karl
Tony
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Re: FreeEMS design guideline

Post by Tony »

Not a problem i will get you some foot prints made up if you want them.
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Re: FreeEMS design guideline

Post by Tony »

Ok i got the fuse holder and relay socket footprints made now.

The link for the ECU connectors witch one do you need all of them?

When im done i can send these footprints too you if you like just let me know. ;)
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Re: FreeEMS design guideline

Post by Tony »

Fred wrote:Tony, Odd ball is the original Turbo FE3 engine in a truck guy. He's the one that inspired me to go from "no idea about boost and ecus" to "boost and ecu eeeelite" ;-) IE, I saw his truck and started researching stuff years ago. Before that I didn't have much of a clue about anything. So, if he can be looked after, we should :-)

Odd ball, I didn't know you were into your electronics? Great to see you posting! :-)

Fred.
I see i will do what i can. ;)
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Fred
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Re: FreeEMS design guideline

Post by Fred »

Tony, relax :-)

I *think* those were examples. I'd say probably let Karl ask for them first.

We don't want you all burned out from doing 10000 footprints ;-)

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
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Tony
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Re: FreeEMS design guideline

Post by Tony »

Fred wrote:Tony, relax :-)

I *think* those were examples. I'd say probably let Karl ask for them first.

We don't want you all burned out from doing 10000 footprints ;-)

Fred.
LOL No problem its good exercise for my brain all those wacky datasheets some of those damn Tyco sheets, whoever wrote those things need kick in the head they leave off some of the measurements witch makes it next to impossible to get them exact.LOL

Im making a new 6 layer board up so a foot print is simple compared to that.LOL
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jharvey
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Re: FreeEMS design guideline

Post by jharvey »

I've been thinking of starting a draft schematic for freeEMS 1.0. I thought I would toss out some notes about it here. I'm planning on the following

using kicad because of it's portability
a single board that attaches to the tech arts board
starting by capturing the power reg circuit posted by Fred
6 input circuits
as many inductive driving circuits as reasonably possible
release as a zip file
revs will be A, A.01, A.02, ect until a the first draft is done, the it will be B, B.01 ect.

Things I'm not sure about, include the following

general schematic for driving the inductive loads, what chip is best?
generic input circuit, or perhaps generic won't cut it? I'll draft one up, but I'll also expect comments.
where should it be posted, here, a CVS somewhere, other?

Thoughts welcome.
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Fred
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Re: FreeEMS design guideline

Post by Fred »

If you mean injectors and relays etc, the normal compliment of self protected FETs are ideal. They can be driven with just a single resistor from the CPU output. In terms of ignition, I would recommend you leave it off the board and instead install 6 self protected mini to92 FETs to drive external ignitors with a pull up.

6 inputs are actually 7.

2 thermistor resistor bias circuits
1 conditioned MAP input
1 conditioned TPS input
1 battery voltage conditioning input with external source
2 rpm inputs. These are the tricky ones. For hall devices a basic protected (clamped to both rails) input is enough, but with VR you need to use one or two lm1815 devices. The general idea is to be able to jumper them in and out for different uses easily.

I'd recommend at least 4 and preferably 6 5Amp+ FETs for saturated injector driving and one of the same for the fuel pump relay. I'd also recommend 6+ to92 drivers of some sort to buffer the CPU to external devices, particularly for the ignitors.

So, 7 inputs, 7 large FETs, 6+ small FETs/BJTs, power supply setup.

BTW, I think my drawing was flawed, but it's been a while. I forget my thoughts on it, hopefully I posted them.

Spare extra FET's are obviously good to have, but don't forget heat dissipation requirements :-)

What I've listed above is pretty much the bare minimum for a 6 cylinder install, a 4 cylinder could be cut down a bit on that.

What do you think of that?

Fred.
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!
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