Making your own printed circuit board can be a truly satisfying process, tying together electronics and the handmade craft of etching. It’s the most accurate way to build a circuit short of sending away to a PCB manufacturer and it’s a lot more fun (+ cheaper too!).
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my question is in the etching process. I was curious, do you guys have any tips in the disposal of the chemicals. organizations??? or a process were how many times i can reuse my chemicals in the etching process. with out endangering the environment.
Ferric chloride isn’t that bad — at least the stuff I got from Radio Shack (part #276-1576). While etching PCBs in the past I’d gotten it on my skin and not noticed. Never got burned but it did stain the skin yellow. To discard used ferric chloride, I just dilute it with cold water and flush it as per the instructions on the bottles I got from Radio Shack: “Discard used solution into toilet bowl and flush.”
A little FeCl3 goes a long way but in my experience, it doesn’t store well once you’ve dissolved some copper in it. I’m nearly out of FeCl3 (only about 2 oz unused FeCl left, which can do several small boards) and my local RS closed down a couple years back. I picked up some muriatic acid from my local Lowe’s, and it was extremely cheap compared to the FeCl3 from RS. Will be trying the muriatic acid and peroxide solution etchant once I’m out of FeCl3.
I really like the video Collin put together (thanks for posting this, Adafruit team.) I’ve been using the laser toner transfer method for a few years now but I’ve been meaning to go to the photo-resist method for about as long, just haven’t gotten the stuff together. I’ve recently gotten to the point where I’m butting up against the resolution of the the laser toner transfer method (TQFP AVR mcus.) I like his idea of using the photo frame and desk lamps. That hadn’t occured to me. I think I’ll hit my local *mart tomorrow and pick up two inexpensive medium frames and two desktop bendable lamps and see about using the glass from both frames to make one double-sided frame.
Oh, I’d forgotten but meant to ask: Collin is using pre-coated boards. I have a bunch of double-sided copper clad boards here, so I’d like to use them up. Anyone here have experience coating boards with photoresist? I’ve seen sprays online. Any gotchyas to look out for?
@Nomen I’ve yet to use spray coat myself but have heard it can be a challenge to even apply it & avoid streakiness. I’m guessing w/ some attentive practice (ideal spray distance, etc) results would improve.
Hey guys, can someone post instructions on how to print out multiple copies of the same board when using EAGLE CAD? What are the steps?
I want to use the opensource Boarduino designs but don’t know how to print it in the right scale on paper and I’d like to print multiple copies if I’m using the kodak paper?
using 1 printout on one whole sheet of glossy paper is such a waste IMO.
And after etching, how do you apply the green layer and letters in white? Is a DIY procedure?
Colin: I’ll have to give it a try soon.
YoYo: I don’t use Eagle myself, so I can’t give you any direct info, but look to see what formats Eagle can export. If it can export to pdf, ps, or EPS, you might be able to compose multiple copies together in another editor like OpenOffice or such. Not sure — never tried it myself.
Since you’re using paper, I assume you’re using the laser toner transfer method? If so, you may want to try using glossy paper from junk mail or catalog covers. That’s what I use since they’re free and I have a never-ending supply. It can be a bit hit-or-miss, though, as sometimes the color ink(s) used in the advertisement or catalog may transfer depending on what type they’re using. Also, too thin paper has a tendency to jam in my printer but YMMV.
Gus: I coat my etched boards with two layers of shellac using a brush before I drill, or just one layer if I’m in a hurry. Allow the shellac to dry fully between coats and before drilling. I’ve also applied the shellac after drilling holes and soldering in surface-mount parts, but before mounting through-hole parts. Shellac is clear, not green, but it helps to protect the surface from corrosion. I’ve seen online where some have also used clear spray-paint, but I’ve never tried that and I would think some experimenting with different brands and colors would be in order before-hand if you decide to go that route. You can silkscreen your white lettering before mounting your parts, but I’ve also never done silkscreening. If I require lettering, I just etch it in the copper.
MG Chemicals makes a dry film photoresist that can be applied to copper clad boards using a laminator. Neat. If applying spray resist turns out to be too sloppy, the film looks like an interesting alternative.