Connector considerations

[AbeFM]

I hate to bring up an old topic, but I found something which I found to be of interest. Here at work, folks are always coming by to show us their connectors, and I found THE COOLEST one.

It's a DB-37 shell, mounting, etc, but with smaller pins (still 5 amp/ea), in three rows, for a total of 62 pins. They make various high density DB's. They seem identical to the normal ones, but with more pins.

The biggest drawback is they aren't as universal as the standard connectors. Personally, I don't think we'll do better than as-many-DB____-as-it-takes for a solution, but this is an exciting alternative.

My only other suggestion is to find some reasonable OEM connector.
-Abe.

[AbeFM]

Perhaps using an OEM connector for the FreeEMS is a good idea, cheap and easily had? Another thread, anyway.

Yeah, this thread

You can order those brand new too. The trick would be standardising on one and choosing which one it should be. The OEM ones from japan at least aren't waterproof either. I personally don't mind Jared's inline idea provided the wires come cleanly off the board.

Fred.

I just don't trust soldering the the board. I don't know where all your failures of through holes have been, but I just haven't seen them. A right angle connector is a great solution, they work well, can be very rigid, and you bolt it to the board.

Failing that, I've always liked the cute trick of soldering soldercups to a series of pads on the edge of the board:
which could be done with DB37's just fine. Takes up virtually no board space, probably less than wires from all over the place.

[AbeFM]

By request, I'm donating one of my paintings to the cause. I hope it sells well and brings money to the project

[Fred]

Ahh, I see, recess the board, makes perfect sense :-) I like it! What about the extra cost of non rectangular boards?

Can you get more details for the HD DB stuff ?

Thanks for that!

Fred.

[WTDeuce]

Why not just go with AmpSeals? Theyre proven in EMS uses, weather sealed, seem pretty tough, can be had in through hole, and IMHO arent that expensive.

$16 for a 35 pin one. Its a shame they dont have a 50 or 60 pin one, but oh well.

http://mouser.com/Search/ProductDetail. ... 8PqQ%3d%3d

Personally, I HATE DB connectors for this use.... But thats me :p

I know theyve been discussed but their downsides seem to be much less than all the others. Theyre available at Mouser, so I dont think availability will be an issue. 35 pins probably wont be enough, so its $32 for the EMS side for 70 pins which should be pretty sufficient for any install. The current rating of the 35 pin one above is 17A per pin, which is more than 3 times that of a DSub and eliminates the need to combine pins for things like coilpacks and power wires (which just wastes connector space). While slightly bulky yes, once you factor in the bulk of having a wad of wires behind another connector that all go to pads on the board its a savings. And the high current rating per pin makes up for the bulk.

Edit: Mating connector, which seems to be low on stock ATM. Also $16 though.

http://mouser.com/Search/ProductDetail. ... 98IA%3d%3d


Edit2: Interesting info on Octopart showing some good distributors. Most of these places will sell to individuals. $16 seems to be average, but theres one place at $10 in single quantities.

http://octopart.com/info/Tyco+Electronics/776164-1

[Fred]

Thing is, there is no way we'll ever agree on this :-) Hence we should do a simple effective db or no plug variant up front and allow those that care for whatever reason to design something better later. It's (true!!) open source, you can do what you please here :-)

Fred.

[WTDeuce]

Thing is, there is no way we'll ever agree on this Hence we should do a simple effective db or no plug variant up front and allow those that care for whatever reason to design something better later. It's (true!!) open source, you can do what you please here

Fred.

I do agree wholeheartedly with that, however I can see there being a large group of people who will want to look at a BOM, buy that list of parts, order the board(s) that suits their car/price range/color scheme/what have you, and solder it together, and have a full featured functioning system. This was the draw of MS for many people, just being able to have a list they can look at and have the fun and challenge of putting together. So IMHO having a nice base board design with a standard connector is an excellent idea. And the further upside of the AmpSeal is that it has a nice big pin spacing, so if someone wants a different connector is easy to solder wires to those holes. If someone wants to design a board that uses something else then yes thats the point of the system, but arent we also trying to get away from the MS mindset? The DSub kinda sorta almost worked sometimes for a base MS, but once you had people modding things for Wasted Spark, COP, a better Low-Z driver board, 3 wire idle valves, table switching, cam sensor, etc then the DSub went from a mere mess to an utter disaster. Been there done that which is why im so opposed to them.

[jharvey]

Ohhhh, I'm hating my browser right now, just lost a post because it crashed. I'll try to repost what I had written come luch break.

The quickly about my last post was that a single connector forces you to combine data and inductive drive wires together allowing antenna coupling, to VR and Hall signals. So I think we're really looking at 2 amp-seals not one. Also I think the amp-seal is a friction fit with a detent to change the friction on insertion. I don't like this because it doesn't give you a confirmation you have full pin penetration. It really needs to lock some how that's obvious. Very few auto connectors simply push and pull apart. Most require some form of snap release to come apart.

I like the AMP CPC series connectors. Here's one example, but there are many options here, so this is just an example.

Tyco number 1445759-1 and here's a link to a PDF.

http://documents.tycoelectronics.com/co ... DocLang=EN

Basically, they offer twist lock, weather tight, separation of power lines vs data lines, PCB mount or harness mount, crimp or solder cup, a variety of coatings, they are circular and perfer circular holes for easier fabrication, and don't cost an arm and a leg.

[WTDeuce]

I have Amp CPC connectors on my MS. They are very nice for this, but there ARE a few downsides. First is that they arent available in a right angle PCB mount, so there would need to be a vertical board of some sort that connects to the main board, or we have to go with wires to the board. I currently have the wires going from my MS to the case connector, and its quite a mess. It adds to the size of the case, and is quite awkward to deal with once you add in thicker wires for things like coilpacks. Then theres cost, that one you linked to is almost twice the price of a 35 pin AMPSEAL and it has less pins. Theres cheaper CPC connectors but theyre not weather sealed, I dont know of that matters or not for everyone but its a difference.

I dont think running everything through one connector is going to cause a problem. Most EMS's do it in one form or another already. But if it is a worry, its easy enough to have multiple connectors, like a 20 pin one for hall sensors, TPS, temp sensors, whatever, then a 10 or 15 pin one for injectors, large grounds, 12v supply, coilpacks etc. Thats what I have now, but thats also because the high density CPC connector pins have a current limit of 7.5 amps and thus cant handle my coilpacks. So I have a high density 63 pin connector, and a low density 9 pin connector.

[AbeFM]

So IMHO having a nice base board design with a standard connector is an excellent idea. And the further upside of the AmpSeal is that it has a nice big pin spacing, so if someone wants a different connector is easy to solder wires to those holes.

Ok, that idea I like - lots of space.
What I don't like is... lots of space. If someone's going to complain over losing a few square millimeters of board with my DB hanging off the side , then all the overhead for the ampseal drives me batty.

And of course, buying both ends of the connector will drive the cost up - that's $64 (if I understand correctly) for both connectors on both sides. So now I'm paying more to get wasted board space, a bigger box merely to accommodate this, and now since the connector is water tight, I need to water tight the whole box - seals everywhere, more work on designing the case... why not just do what the OEM's do? Put a reasonable box around a reasonable board, and put on a connector?

If someone wants to design a board that uses something else then yes thats the point of the system, but arent we also trying to get away from the MS mindset? The DSub kinda sorta almost worked sometimes for a base MS, but once you had people modding things for Wasted Spark, COP, a better Low-Z driver board, 3 wire idle valves, table switching, cam sensor, etc then the DSub went from a mere mess to an utter disaster. Been there done that which is why im so opposed to them.

Letting go of the megasquirt mindset also means letting go of pent-up megasquirt bitterness. Yes, we ALL hate the DB-37, but the only reason anyone *I* know hates it is they run out of pins. But, 1/3 of the pins on that connector are redundant. The DB-37 on the MS has 20 pins (22, two redundant pins for injectors, and the rest are grounds). Actually using 5 amp DB-37 would give you 3 short of TWICE the pins you have on a megasquirt. So get over hating it, for that reason.

I've never had a leaking issue (really, for a prototype, keep the damned thing dry - if you NEED to mount your EMS to your spoiler and drive in the rain, put a bag on it. I put mine under the dash and it's 100% a-ok), for the money you want to spend on connectors, you could build a water proof box. And there's nothing keeping you from building a bigger case, and soldering wires to a pair of DB-37 footprints and up to your connector for those who need submersible ECU's.

I wouldn't want to spend the money, and HATE to have a bigger box, for water proof that doens't do me anything, a lack of a positive lock... I just don't see what doesn't work on DB's.

Basically, they offer twist lock, weather tight, separation of power lines vs data lines, PCB mount or harness mount, crimp or solder cup, a variety of coatings, they are circular and perfer circular holes for easier fabrication, and don't cost an arm and a leg.

The mounting seems like a plus. There's not the highest of densities - at least in the height dimension. I do like that it's seperatable, and you could "key" it easily? I guess by using different sizes. Perhaps for the big signals it would make sense - power and coils (not that I like direct driving coils) and injectors...



As to the non-square board... I'm thinking about that. Right now I would think you'd leave the connector sticking out, and either let the parts hang over onto a heat sink (will show soon in a pic) or put the connector through the case.

I think a through hole set of DB's (likely a 15 and a 37) will cover all the pins we'd need, be unambiguous, be EASY to find anywhere, cheap to implement, and flexible if someone wants to use some other sort of panel connector.

If I didn't care for flexability, I would do as drawn above with surface mount pads and a DB - which seems to keep people happy avoiding vias.

Stay tuned for my "what to do with the overhang" picture. BTW - how much space would two DB-37's take verses twoi ampseals? Ampseals are NOT small... Do they FIT on eurocards?