OT: DIY Printed Circuit Board ????, For Programable Ignition Options

[Mueller]

MegaJolt EDIS



I'd like to build this PCB if the group buy takes too long to materialize.

I've seen a few websites that show how to make your own PCB and it does not seem too difficult, any pointers or tips or links to an outstanding DIY PCB site??

Thanks

[fiid]

My roommate gets pcbs made all the time. I think it's pretty easy if you can get the source design file for the PCB. Cost is not prohibitive - although is a little steep for low volumes.

I'd go in for one - I'd like to see this stuff working.

Fiid.

[ss6]

I've used http://www.expresspcb.com for prototype ckt bds and they are great. If you can stick to their "mini-board" footprint, you get 3 for a little over $60 fedex'd to your address in 2 days. You'll have to copy the design, but they provide a downloadable pcb design package too. You're limited to 2 layers, but the pcb you're interested in appears to be 2 layers and small enough to fit.

[garyh]

I'd like to build this PCB

I see you're still real cavalier about ripping off copyrighted designs.

[ss6]

Suggest you check out the site - http://picasso.org/mjlj/index.jsp, specifically the part where it says

"The design is covered under a variation of the GNU Public License- you're free to copy and modify it, as long as the modifications remain public. No warranty, expressed or implied, is provided- so if you blow up your engine, it's your fault! (IMG:style_emoticons/default/smile.gif)"

[Mueller]

you're free to copy and modify it,etc, ect.......

I knew that, but thanks for letting others know it as well (IMG:style_emoticons/default/smile.gif)

[GWN7]

I remember reading a site that showed how to make DIY PCB while researching bootstrap boards. If I remember rightly you use heat transfer paper to make the circuit outline and a simple acid wash to remove the unwanted material. I built one in grade 7, but that was a long, long time ago. I'll check to see if I saved the link when I get home from work.

There is these books: BOOKs

[airsix]

Mike, here's one way to do it. There are probably better ways, but you can give this a try - it won't cost anything. Get a PCB kit at Radio Shack for like $9. It's got a board for etching, and a bottle of ferric chloride. Now get your diagram ready on the computer so you can print it out 1:1. Here's the trick though - you have to mirror the image with software before printing. If you've got photoshop or Paintshop Pro you won't have trouble doing this. There are special kits that let you print your circuit design and iron or stick it onto the board for etching. Here's how you can do it without a transfer kit. Get a Avery label sheet and peel the labels off so you are left with paper that is kinda waxy on one side. Now print your circuit onto the waxy side of the paper with a lazer printer. Handle it very carefully because the toner will want to flake off the paper. Now lay the paper printed-side down on your board. Use your wifes clothes iron (while she's not home) to heat the back side of the paper. When you have it nice and hot just leave it to cool or run cold water over it. Don't lift the paper while it's hot or you'll have a royal mess. When it's cool peel the paper off and you should have sucessfully transfered the toner image right off the paper and onto the copper board. Because you mirrored the image when you printed it the transfer should now be correct. Check all the traces to make sure everything transfered correctly. Use a sharpy marker if you need to fill in any spots that didn't transfer toner correctly. The toner and sharpy ink will act as resist. Now dunk that sucker in ferric chloride per the instructions in the PCB kit, and you've got yourself a custom circuit board (as soon as you drill it).

You might want to pick up extra board matterial since you might have to do a couple to get the hang of it.

-Ben M.

ps - What's up? I thought you did this for a living?

[Mueller]

Thanks Ben,

I found a site earlier today describing that process, sounded too easy (IMG:style_emoticons/default/smile.gif) (famous last words, LOL)

ps - What's up? I thought you did this for a living?

not me, I'm mechanical, not electrical...I do "stuff" a few boards at work (most have one IR sensor and a resistor, not too hard), but not 'cause I know what I am doing, just that I am the only one that can read the prints, hahaha

I found out that another offshoot of the Megasquirt will allow me to run the EDIS ignition using my existing MS...I lose the fast idle circut, but that is no big deal since I never had it activated (it would drive a stepper motor). If I do end up having cold start issues, I can always use a cold start valve like the stock 914 motor uses.

The board I showed can be used in conjunction with a MS or standalone so that one can have a distributorless programmable ignition (crankfire) for use with another FI (stock) or carbs.

[ss6]

Don't bother with Radio Shack, heat transfer paper, etching acid, etc, etc - used to be that was the only approach available for us weekend warriors, but it's way obsolete now.

There are now a number of manufacturers who specialize in low volume, fast turn-around pcb services over the web, one of whom I mentioned above. They provide free CAD programs that allow you to lay out your pcb, you upload the file, and a couple days later, you get a few copies of your pcb delivered to your door, for not much more than what the R/S pcb kit costs. I do circuit design, have used these guys, and they are awesome.

The biggest problem with those pcb kits, in addition to the time and the mess, is that you have to drill the holes (tiny, tight tolerances, lots of them) yourself. BTDT, PITA, NFW.

BTW, I'd wait for Mr. Picasso to get a little mileage on his design before I got too excited about it. Looks like he's doing a thorough job, but it ain't over till the fat engine sings.

[DNHunt]

Mike

I'm not sure any of the Megasquirtnspark stuff is running on cars yet, but I think that is the way I'm going to go. I'm going to wait until late winter and let other people work out the bugs.

I've been using the fast idle circuit on the MS to control a fast idle solenoid. It is not a pulse modulated circuit and will not control a stepper motor, so it is either on or off and is triggered by CHT. It's not a very good solution. The old AAR is much better so I won't cry over losing the fast idle control.

I don't remember for sure but the modifications are minimal so they should get it working and driving soon.

Dave

[applescotty]

I'll have to agree with John on this. If you're wanting to actually make a PCB, then the iron transfer method is fun, although drilling all the holes is a bit of a pain. But, it's an educational way to use up a few evenings. Otherwise, I'd send it off to a board house. A place like Express PCB or Alberta can do it pretty cheaply, and if you're just wanting to have the board, it's worth the cost. Have a few made up, then sell them off. A few boards isn't much more than one.

applescotty

[garyh]

Suggest you check out the site - http://picasso.org/mjlj/index.jsp, specifically the part where it says

"The design is covered under a variation of the GNU Public License- you're free to copy and modify it, as long as the modifications remain public. No warranty, expressed or implied, is provided- so if you blow up your engine, it's your fault! (IMG:style_emoticons/default/smile.gif)"

If you look at the artwork, is has the words "copyright 2003" on it.

That would exclude that portion of the design. If it was "GNU", it would say "copyleft".

[krk]

Suggest  you check out the site - http://picasso.org/mjlj/index.jsp, specifically the part where it says

"The design is covered under a variation of the GNU Public License- you're free to copy and modify it, as long as the modifications remain public. No warranty, expressed or implied, is provided- so if you blow up your engine, it's your fault! (IMG:style_emoticons/default/smile.gif)"

If you look at the artwork, is has the words "copyright 2003" on it.

That would exclude that portion of the design. If it was "GNU", it would say "copyleft".

(warning: I've not looked at the site -- but I live in a GPL'd world :-))

We seem to be mixing copyright and license.

The GPL is a license to use, not a copyright. The easy example -- GCC (the FSF's C compiler -- used to build linux, for example) is licensed to the universe under the GPL but the copyright is strictly held by the Free Software Foundation.

The Linux Kernel is distributed under the GPL, but the copyright for the sources are held by lots of people.

So Mike needs to be aware of the license, as that's what does or doesn't give him various rights of use.

Warning: I'm not a lawyer. YMMV. Offer may be void where prohibited.

kim.

[mskala]

John has it right, I've used them for a number of things on the mini-boards. They
work fine and are cheap for low volume. If you are making a bunch, they or others
will make them even cheaper. Don't waste time etching and drilling this stuff.

[Mueller]

Update:

I e-mailed the "owner" of the above mentioned PCB that I was talking about making myself:

Hello Brent,
Just a quick question if you don't mind? (IMG:style_emoticons/default/smile.gif)

I showed your site with the PCB for the MJLJr to a
few EE friends of mine and I got hammered for
wanting to make this board (for myself), they say
that I  cannot legally make it due to the ©
copyright of the board.

Can I get some clarification on this??

thanks,

Mike Mueller
(getting accussed of "ripping" off someone elses PCB
design?!?!?!)

Sure, that's easy. (Hmm, I was hoping that it was a
technical flaw that they hammered you on. (IMG:style_emoticons/default/smile.gif) )

Like the Linux operating system, the MJLJ is
copyrighted under the GNU public license. take a look
at the license at http://picasso.org/mjlj/license.jsp
.

This basically says that you're free to use, copy or
distribute it, but any changes/improvments must fall
under the same license as well, and therefore remain
in the public domain, so it best serve the community.

So the only thing that the copyright indicates is that
the're a license attached to the intellectual
property. that's all (IMG:style_emoticons/default/smile.gif)

Hope that helps.
Brent

[ss6]

So much for your cavalier disregard...

Mike, what's your interest in this gizmo? Has Brent gotten something working?

[seanery]

i hate those damn cars anyway.

crappy lil chevies.