Set myself a simple task to wean myself off protoboard and on to reading/creating schematics, PCB design in Eagle and etching boards at home.
The schematic, a MIDI in/out breakout board for an Arduino project.
The board layout.
Bottom layer and pads.
Mirrored mask for etching printed to reverse (emulsion) side of Press-N-Peel sheet and ironed on to single-sided copper clad laminate.
The etched board, copper side up.
So far so good? Well no ... presumably I'm supposed to solder to the copper side with the components on the reverse side ... not a problem for the MIDI sockets, 4-pin molex connector, diode and resistor but ... if the IC (a 4N25 opto-isolator) is on the other side then it's pins get reversed!
What should I have done differently? Where did my thinking go wrong? Did it not need mirroring and if not then why do all the etching guides say reverse it?!
... eh ... Ok ... thinking about it ... I didn't visualise the bottom layer as the bottom layer did I? It didn't need mirroring because it was always mirrored anyway as I was "looking through" the board if you will at the bottom layer.
So it's only traces on the top-layer that require mirroring? Not that there would be any on a single-sided board.
Set myself a simple task to wean myself off protoboard and on to reading/creating schematics, PCB design in Eagle and etching boards at home.
While I can't answer your question as to what went wrong, and you are clearly ahead of me (etching boards); never discount using protoboards. Indeed, for most purposes (ie, one-off designs you have no intention of replicating or commercializing), protoboard developed circuits will serve the purpose just fine.
There are only a few reasons to consider anything beyond a protoboard, IMO. Such reasons, as those listed above, include knowing when your design will work on a protoboard; typically if you are dealing with high-frequency or high-voltage designs, a custom etched or manufactured PCB would be the way to go (though with some high-voltage designs you may have fall back to point-to-point wiring!).
Depending on what you are doing, etching a single PCB for each circuit you build may actually take more time and cost you more money than building it using a protoboard. As noted, though, its a different thing, though, if you intend on making more than one instance of the device, or for commercialization purposes.
Finally, of course - as you are learning - you must make a few PCBs in order to learn the process. Hopefully someone else here can answer your questions.
... eh ... Ok ... thinking about it ... I didn't visualise the bottom layer as the bottom layer did I? It didn't need mirroring because it was always mirrored anyway as I was "looking through" the board if you will at the bottom layer.
So it's only traces on the top-layer that require mirroring? Not that there would be any on a single-sided board.
Is all that right? I'm confused ...
That sounds right to me, but once again I would wait for an informed opinion as to what went wrong...
There are only a few reasons to consider anything beyond a protoboard, IMO.
Even for one-off builds, I still like having a PCB for any circuit I might want to use again later on. The PCB tends to be a cleaner implementation, since you have probably debugged the design on a prototype already.
Plus, by working back through a schematic capture step, you give yourself some very excellent documentation.
Thanks! First attempt as well. I expected the etch to go wrong not the design Do you know the Press-N-Peel stuff? I think that helped a lot, it transferred very easily onto the board. Plus I used my own laser printer to get the toner on it (mono lasers have got very cheap now in case you haven't looked lately) rather than a photocopier in a shop which I imagine is better for no reason other than I had control over it and didn't have to worry about the staff wondering why I was feeding sheets of blue plastic into their expensive copy machines!
All I have to do now is learn how to cut in a straight line
Don't forget to account for no thru-hole plating on home made boards!!!
You have to either keep traces to the correct side so you can solder them, OR add adjacent vias so you can solder the 2 sides together with a wire or something.
I also try to make my pads,traces and spacing bigger on a home etching as extra margin.
Haha, bad quality pins then ? I've had to do it a few times and none of the pins broke!. I think I didn't make the bend as close to the package as possible (what kinda happens automatically) but a little further outside.
Maybe I'm missing something, but why don't you just solder it to the bottom of the board, the electrons don't care. It will look a bit funny but if you don't have a clearance issue there shouldn't be a problem with components on both sides.
I did a pseudo silkscreen! You can just see it by the MIDI ports. I labelled them and I labelled the 4 pin connector. I thought I probably didn't need to label the components as there are only 4 on the board
I'm quickly realising that a single-sided board will only take me so far with the projects I have planned and too many air wires seems to begin to defeat the purpose. People must have devised some foolproof methods for accurate aligning by now? I'm thinking - drill alignment holes through printout/board/printout while sandwiched together and then mount the sandwich on a piece of wood with pegs sticking out (like the used to do with handdrawn cell animation). That would keep them aligned but then the pegs would get in the way when it's time to start ironing ...
Doh! Didn't see the silk screen in the pic, nice work!
I'm thinking - drill alignment holes through printout/board/printout while sandwiched together and then mount the sandwich on a piece of wood with pegs sticking out
That's one way of doing it...
I've never done one yet (i have a dual sided board waiting though), but my plan is to use a 'folder' type of system combined with a couple alignment markers on the board layout (could easily be components or something added to the board).
Take the top and bottom sides of the board and print them side by side with an inch or so gap between them.
Oversize the bottom layer, but cut the top layer to the exact size of the board (using the dimension layer in eagle).
Crease the 'folder' using the alignment guides on the layout to help. Crease VERY well to ensure proper alignement.
At this point you should be able to slide the board between the folded paper and secure it to the bottom, then the top layer. The rest is as before, except be sure to iron both sides!
The most important thing that will help is to oversize your via's so that in case the alignment isn't 100% perfect, you have some 'wiggle room' that should eliminate any issues.
Then it's just a matter of drilling and soldering small wires in the via's to connect top and bottom. For that I would use wire just ever so slightly smaller than the hole. Insert some wire and solder one side, then solder and cut the reverse side. You may not be able to hide the via's under small components as the 'pros' do due to the hight of the via's but that's a minor inconvenience.
When/if I ever get around to trying a double sided, I will try to do a video guide of the important steps in the process.
