Thanks for this. I guess I've always gotten lucky here but now I'm imagining the frustration of getting done with all the discretes on a board just to blow it all on the uC. Great advice, thanks again.
Been doing a design proposal for a yet another ultrathin laptop, this time with "pro gaming" spin.
One of client requirements was "be it the end of the world, but switches must be mechanical."
That sounded like an easy task... , but we ended up spending a week on the switch and having them custom made by a watch parts factory.
It is remarkably difficult to design a purely mechanical mechanism for making a "snapping action" that will be small and moderately wear resistant.
We almost thought of "screw that, lets make the mechanism electrostatically actuated," but finally made a parallelogram mechanism with just enough set of spring loading there, and there
https://support.wasdkeyboards.com/hc/en-us/articles/11500927...
As for the ground plane [0], you usually want this uniformly connected despite the grid routing of the matrix. But since there is no connection on the plastic pins you can use these holes for that instead of making a bunch of other connections.
[0] https://en.wikipedia.org/wiki/Ground_plane#Printed_circuit_b...
I would recommend that if you're new to surface mount, to get a couple of SMD practice boards so you can exercise your skills and get a feel for what will be hard/risky and what will be easy/repairable. They're a few dollars online.
No idea how can i make DC to DC UPS with easily available items
I've 12v 0.5amp requirement @6watt.
I need this appliance to be running for 5-6 hours when power has failed.
Does anyone know of the community where I can ask such question?
1. Get a through hole supported usb connector instead of a pure smd one, since the latter likes to fall off.
2. I would avoid routing under the switches for durability, this might just be superstition though.
3. You can route the x and y of the matrix on different sides of the board to make things easier.
4. If you want to pick and place or wave solder it is probably easier to have the smd and through hole parts on different sides of the board.
5. No reason not to use the supported switch footprint, especially since you can connect your ground planes with the additional holes. (well, I guess space is a reason but still).
6. If you are going to assemble by hand, make the pads longer as needed. Probably especially on the microcontroller and diodes.
7. Solder in order of cost and success rate.
8. Always add switches, leds and connectors for debugging even if you don't intend to use them.
9. Some traces are quite close to the center hole, which might also be too small? Anyway, some margin is good for reliability/yield. (especially mixing 'technologies' e.g. holes/edges and traces).
Edit: Oh, I forgot. You might consider scripting the placement of the switches/diodes.