A few things I learned about PCB design…
Published by rich on Tuesday, January 8, 2008 - 07:26:35 - Filed under Robots and Electronics
I recently got my first batch of “MeltyBoards” in the mail from BatchPCB.
The MeltyBoard may someday be available either commercially or as open source hardware for people doing Melty Brain combat robots.
For right now it’s mostly a general-purpose board with some extra goodies based on an AVR Atmega168 (and for SpamButcher internal use only).
More info on the board’s design is here.
Here’s a few things I’ve learned from initial testing:
1. BatchPCB is a great, cheap way to get boards made (mine came out to about $10 / each + $10 per-order-setup and shipping). Eagle is a bit difficult to learn, but probably not more so than any other PCB design program (and it has a free version). Look at the tutorials here and here.
2. Do a schematic first, then do the layout. Eagle’s auto-routing is pretty cool, and can be tweaked afterward.
3. You absolutely, positively want to have a small (.1 uf or “104”) capacitor wired in parallel to your power supply after your voltage regulator. If you don’t - anything that requires significant power may cause a reboot.
4. Those pins “AVCC” and “AREF” need to get wired to +5v - at least if you want get usable ADC (analog) readings (yes, even if you’re using “internal” for the ADC).
5. Don’t wire up an ultra-bright blue LED as your main indicator LED. While cool at first, it will eventually make you go blind, and insane from chasing the after-image around the room.
6. There a tools to help you determine how wide your traces need to be for a given amount of power.
7. Tiny little traces can quickly be vaporized if you accidentally run 15 amps through them (related to above).
8. When designing on a 19” monitor, it’s easy to forget how big 1.5”x2.5” is. Small type on your screen may be too small to read when printed on the board.
9. It’s easy to get sucked into PCB design, and forget about everything else. For instance, I made it this far into the page without mentioning what a great piece of anti-spam email software SpamButcher is.
