Connector considerations

[Fred]

Hi, welcome along, nice username by the way. We need a matching "pinknoise" member now ;-)

Nothing is set in stone at all. I've got a lot of ideas about how I see that it "should" be, but I'm totally open to suggestions. Those look nice. Can you get the cases like that too? or is that an oem one that you've used?

Thanks for posting that. Most appreciated.

Admin.

[whitenoise]

Thanks....username is inline with your suggestions in the announcements section

The case is actually that of an OEM Denso ECU from an early miata.

[Fred]

Good move. Nothing would surprise me. I'll post something up in that thread in a few minutes for you and others to see.

I thought it looked a bit mazdaish :-) Then again, they all look very much like that really.

[Rotule]

Hi, my name is francois and i am new to the site but not to ECU design, I build ECU for a formula racecar since 3 years now.

i wanted to let you know a few points about my experiments with conenctors.

i know for prototyping DB25 is perfect, but at last if you want a complete product, you will need a real automotive connectors and the reason is simple : reliability

1 : most db25 connectors are solder lugs . in race application , soldered wire tend to break because of vibrations and cause failure.

2: i already used the ampseal connectors : the problem is that the female pin (on the cable side) is a bit loose when connected (at least not tight enough) and this caused me a lot of intermitent problem.

3: i used the Econoseal connector also from amp (they can be bought at the VEMS web shop http://shop.vems.hu/catalog/index.php?c ... 9b9c7ff2a8): electrically i had no problem. but it is a bit difficult to disconnect and it finally pissed me off.

4: from now, i still use a amp connector, the same used on the MOTEC M800 ECU, i think we buy them directly from motec. let me tell you that this connector is AWSOME. you don't even need a screedriver to remove the pins, every thing snap in very tight and it's easy to unplug, perfect for racing application.

i wanted to share my experience in the domain.
i will now try to interract with you more on the forum and once i have some spare time i will try to contribute more.
i like open source !

i don't know much about HCS12 (i used them in a course at university..) but i worked with severals micros and we are all here to learn!

[Fred]

Hi Rotule,

Welcome aboard!

Thank you very much for sharing your experiences with us :-)

The hard thing that a lot of people are possibly not grasping properly yet is that the core idea here is to have a design available that absolutely anyone can afford and build.

When I say we have to use DB, I don't mean for everyone, and I don't mean on all designs, I simply mean on the first and simplest design that can live on for those with very low budgets to use. I'm all for all sorts of flash connectors etc, esp under harsh conditions, and when I have work, I can afford whatever I like too, but all of us (well, most at least) have been a poor student etc at some time. I don't want to forget about such people who will struggle to buy the CPU card, let alone a flash case and connector.

That is why I want the first design to use DB connectors.

Also, in reality, most people using this will be using it on (relatively) softly sprung road cars. MS has taught us that DB connectors ARE reliable in normal road use situations. I know a lot of people don't like them, me included, but reality is that they are "OK", not brilliant, but OK.

Additionally, because the code will be open source, there is nothing to stop someone from reengineering the physical side of the project to a higher standard at a later time. I would really like it though if we all pulled together to help make it a cheap and easy affair at least to start with. Once the code is there and working well, we will find a lot of people designing nice boards and sharing the design or selling them cheaply. Because the source is open, my hope is that there will be a large diversity of awesome hardware to choose from in the long term.

Fingers crossed that I am right :-)

It is good to know about those experiences of yours for sure. I also had heard some stories (second hand) about issues with ampseal connectors.

My good friend Cam who is on this board as walkercam is an FSAE guy too, he has also suggested that :

A solder sucks
B motec connectors kick arse

I know you guys are right, but don't forget why we are here :-)

Is what I have said fair enough? I hope so, but let me know if you disagree.

Thanks again,

Admin.

[AbeFM]

Hi, my name is francois and i am new to the site but not to ECU design, I build ECU for a formula racecar since 3 years now.

...
4: from now, i still use a amp connector, the same used on the MOTEC M800 ECU, i think we buy them directly from motec. let me tell you that this connector is AWSOME. you don't even need a screedriver to remove the pins, every thing snap in very tight and it's easy to unplug, perfect for racing application.

I'd love to hear more about that!

Otherwise, while I think Fred made the case for connectors in space a bit simplified (the launch environment is ridiculous, and thermal cycling can be very demanding) he hit the nail on the head with the "Good enough" comments on DB25/37/9 etc.

One thing about them, they've been around a long time, and many people have had a crack at them. I'll often get the $5 DB37 from AMP over the $2 generic, and I've been happy with them. You can get them rated in several amps per pin. That goes a long way in making them seem better.

Looking at the MS, there's a lot of pins! Unfortunately, they used a pinout inspired by parallel ports, having many more grounds than necessary.

And, if you want to keep the same design, but avoid solder (not that I have issues with it) you can certainly buy crimp DB-connectors. And sure, you can redesign the board to take any connector you want - make a daughterboard to support the other connector.

Long term, I like hearing what people have found works and doesn't.

[Tony]

Hi, my name is francois and i am new to the site but not to ECU design, I build ECU for a formula racecar since 3 years now.

i wanted to let you know a few points about my experiments with conenctors.

i know for prototyping DB25 is perfect, but at last if you want a complete product, you will need a real automotive connectors and the reason is simple : reliability

1 : most db25 connectors are solder lugs . in race application , soldered wire tend to break because of vibrations and cause failure.

2: i already used the ampseal connectors : the problem is that the female pin (on the cable side) is a bit loose when connected (at least not tight enough) and this caused me a lot of intermitent problem.

3: i used the Econoseal connector also from amp (they can be bought at the VEMS web shop http://shop.vems.hu/catalog/index.php?c ... 9b9c7ff2a8): electrically i had no problem. but it is a bit difficult to disconnect and it finally pissed me off.

4: from now, i still use a amp connector, the same used on the MOTEC M800 ECU, i think we buy them directly from motec. let me tell you that this connector is AWSOME. you don't even need a screedriver to remove the pins, every thing snap in very tight and it's easy to unplug, perfect for racing application.

i wanted to share my experience in the domain.
i will now try to interract with you more on the forum and once i have some spare time i will try to contribute more.
i like open source !

i don't know much about HCS12 (i used them in a course at university..) but i worked with severals micros and we are all here to learn!

You mean connectors like this?

[Wiglaf]

Just thought I'd chime in and agree with Rotule, hot-swap power supply connectors or purpose-made automotive connectors are the way to go. Those data db-25 connectors are worthless when it comes to vibrations and humidity.

Also, on those ones that go into space, they are different. The female sockets are quite different and work well, none of the troubles that the computer grade ones will give you. But they are too easy to confuse, I would rather spend the money for a good connector that I know won't be intermittent.

[Rotule]

Tony : yess, i was talking exactly about those connectors : nice big package that you have

andmin : all i wanted to do is to share my experience i really don't want to critism your choice.

I totally agree with the fact that you use DB connectors for the low price and it does the job for you, i only wanted to share things i know from the past, and since people will probalby try and do their own hardware design, i think it is good to give feedback about parts i've used in the past so other people can make their choices.

[ababkin]

Tony : yess, i was talking exactly about those connectors : nice big package that you have

andmin : all i wanted to do is to share my experience i really don't want to critism your choice.

I totally agree with the fact that you use DB connectors for the low price and it does the job for you, i only wanted to share things i know from the past, and since people will probalby try and do their own hardware design, i think it is good to give feedback about parts i've used in the past so other people can make their choices.

let me take on this one for Fred(Admin), since he's away:
Please do feel free to criticize anything as long as it is a.) constructive and b.) reasonable in the context used. One thing we definitely promote here is open-mindedness.
Your experience is very useful and is appreciated, but as Fred mentioned, the target platforms for initial prototypes of freeEMS will be mostly cozy grocery-getters and not the teeth-chattering full-out race cars. Humidity/harsh weather is not an issue as we plan to keep the EMS inside the cabin and not under the hood/bonnet.

personally i also see the DB connectors as mediocre at best, but budget is budget.