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I should make an electronics icon
Oct. 12th, 2013 11:22 pmOne of the things I've been wanting to do for a while is learn how to make PCBs. Not "make" exactly, since I really don't want to deal with all the noxious chemicals involved, but "make designs for and order from a company online."
PCBs are Printed Circuit Boards, the (usually green) boards that all the components get soldered to. The idea is that you lay out your circuit in copper lines on this board, with holes where components go, and then you don't need any messy wires or junk, your whole device is just this board.
There are a lot of arcane tools for designing them, and terminology no one explains, like "mils" (a thousandth of an inch), "traces" (the lines of copper that act as wires in the circuit), and "vias" (a little hole in the board that's filled with copper, to connect traces from different layers). First, I tried to use open-source tools for this, because why not? I eventually gave up on that dream though, after the open-source tools were pretty awful. I finally settled on Eagle, which is closed-source and costs a fortune, but it has a free version that everyone seems to use in the open hardware community. It's limited to larger boards than I will probably ever make, which is fine.
So, I spent last night making this. This is like version 4. It's 2 x 2 inches, which is the size of one quadrant of the button matrix, and the screw holes in the corners ought to line up with the ones on the matrix. The big rectangle in the middle is where I will plug in my favorite microcontroller, and the things along the edges will be where I plug in cables to the button matrix (so I can take it off to mess with the board separately, or to replace with a newer board if this one doesn't work).
I played with several different layouts, this one had the benefit of being both the smallest and the cleanest for laying out the traces. The disadvantage is that the plugs on the sides aren't in any rational order, so the cables connecting it to the button pad will be sort of messy.
After I laid it out, I sent it (in a standard file format, "Gerber") to OSHPark.com. They provide an awesome service: collect board designs from the community and collate them into one really BIG board, which they send to a printing company once a week. It turns out if you do this you can about break even charging $5 per square inch, with free US shipping (helps that PCBs fit in envelopes). They print three copies of each board (like most things, the setup cost is the main expense) so for $20 I will get three copies of my little 2x2 inch board, hopefully next week sometime.
PCBs are Printed Circuit Boards, the (usually green) boards that all the components get soldered to. The idea is that you lay out your circuit in copper lines on this board, with holes where components go, and then you don't need any messy wires or junk, your whole device is just this board.
There are a lot of arcane tools for designing them, and terminology no one explains, like "mils" (a thousandth of an inch), "traces" (the lines of copper that act as wires in the circuit), and "vias" (a little hole in the board that's filled with copper, to connect traces from different layers). First, I tried to use open-source tools for this, because why not? I eventually gave up on that dream though, after the open-source tools were pretty awful. I finally settled on Eagle, which is closed-source and costs a fortune, but it has a free version that everyone seems to use in the open hardware community. It's limited to larger boards than I will probably ever make, which is fine.
So, I spent last night making this. This is like version 4. It's 2 x 2 inches, which is the size of one quadrant of the button matrix, and the screw holes in the corners ought to line up with the ones on the matrix. The big rectangle in the middle is where I will plug in my favorite microcontroller, and the things along the edges will be where I plug in cables to the button matrix (so I can take it off to mess with the board separately, or to replace with a newer board if this one doesn't work).
I played with several different layouts, this one had the benefit of being both the smallest and the cleanest for laying out the traces. The disadvantage is that the plugs on the sides aren't in any rational order, so the cables connecting it to the button pad will be sort of messy.
After I laid it out, I sent it (in a standard file format, "Gerber") to OSHPark.com. They provide an awesome service: collect board designs from the community and collate them into one really BIG board, which they send to a printing company once a week. It turns out if you do this you can about break even charging $5 per square inch, with free US shipping (helps that PCBs fit in envelopes). They print three copies of each board (like most things, the setup cost is the main expense) so for $20 I will get three copies of my little 2x2 inch board, hopefully next week sometime.
