DFH - Defacto FreeEMS Hardware in KICAD

[jharvey]

Do you still think I should drop the drain resistor?

Do you have a scope? I'd say the way to really confirm this is to try it with and with out the drain resistor. See if the wave is nicer one way or another. I would guess the difference will be negligible, but that's only a guess.

You mention it's PWM, these resistors will also change the rise and fall times of the transistor. I suspect your PWM is low enough frequency that this won't matter much. If you can choose a PWM you may want to try lower frequencies if possible.

[jharvey]

I guess I should make a post here, it's been a while. Fred now has checked in the code he used in FL. Sense then, I've found a couple mild problems with the layout. I don't have time to fix these right now, but I'll list them so I remember to fix them when I get a chance. Or if someone else wants to fix them, have at it.

The diode foot print is about .120 wide, but the actual parts are often .140 wide. So a wider diode silk screen foot print is a good idea.

The silk screens use a thickness that is to fat for small text, changing those to a consistent .004 would be a good idea.

Also the version of KICAD I was using is old and I should update it to the newest version. There are many nice new features in KICAD now.

[Fred]

Guys on ms irc were talking about gEDA being good these days? Maybe kicad isn't the best choice anymore? Are the files compatible? I do not know, worth checking though :-)

[jharvey]

I've used gEDA, and found it hard to use. Perhaps the user interface has gotten better, but the screen shots don't indicate a change there. Do they finally offer a windows version? No complaints if someone wants to try it, however it's hard to beat KICAD's usability. I haven't found anything that gEDA can do, that KICAD can't do.

[Fred]

Yeah, you're probably right. At the same time I posted here, I suggested kicad there. He hadn't heard of it/seen it and thanked me for the info/liked it :-)

[AbeFM]

KiCAD is certainly upgraded. There's still a couple things which kill me about it, which they didn't fix, but it's better nonetheless.

I'd love it if resistors could be labeled as symmetric. Yes, I'm a pussy and let some auto-routing occur, but really people?

[Fred]

Just a thought, and I know we might be too short on space, but it might be worth looking at leaving space to mount one of these on the board as an optional extra :

http://www.14point7.com/Widebands/SLC_OEM/SLC%20OEM.htm

It might be possible to stand it up off the board such that various components could live underneath without impacting usable space much. It'd also make for quite a neat little solution without requiring us to TRY (bad idea) to incorporate that functionality into the actual ECU.

Just a thought.

Fred.

[AbeFM]

Sure seems like it would be reasonable to leave a space for it. I think it'd fit quite nicely where those injector and ignition drivers labeled "5" and "6" would be. Physically, it's pretty small, that's for sure!

[jharvey]

Looks fairly small, I think the only real space we need to leave is for those pin connectors to pass through to the board. I think this could sit sandwiched between the brain and the driver board. If we plan for the connector board, it could easily fit there.

[AbeFM]

Isn't there going to be a lot of empty space next to the CPU/brain card anyway? If it doesn't fit BETWEEN them, just have it coplanar with the CPU.

Seems like a really nice card, I wonder how well it works? Certainly seems more attractive than my 75 lb innovative board which always has errors. Then again, it's lasted for years on a single sensor and IS very fast.