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Fail fast, fail often...

April 22, 2013 Benjamin Gray

It's a phrase that's bounded around the web an awful lot. At phenoptix there are only the two of us and most of the failing duties seem to fall on my shoulders, fortunately it would seem that I'm starting to get the knack of it!

Today a new batch of PCBs arrived, designed by yours truly late one evening maybe even with a beer on hand. Well at least I hope I had a beer on hand. The layout was completed fairly quickly as the badge PCB contains only a battery clip and an LED. Using KiCad it was a free and fast process, however the LED contained in the stock libraries only has solder pads on the top layer - this I managed to sort out with a few clicks before sending for production. The libraries are also lacking a CR2032 clip module. I set to work building the said module and got the polarity wrong - first mistake that made it to the finished board!

The idea behind this board was to make a striking badge with a nice shiny logo on it, so I set about emblazoning our logo not just in the silk screen but in the solder resist AND top copper layer. And so created the second problem in the final piece. I had bridged the connections of the LEDs in my fancy copper pour and managed to completely avoid pouring copper into the area that I wanted to make shiny. Bugger! The process of getting the logos into the copper and solder resist is a reasonably long winded but very satisfying one, check out Matt Little's blog for details (Matt is the fella behind our RGB Arduino board).

So what was the damage? 300 boards... all needing a touch with a dremel to undo the bridging and a little sticker placing to tell you to put the long leg on the LED into the other hole. Not too bad really, but considering the simplicity of the board I feel a little ashamed. I checked and checked before sending but next time I will check a little harder. 

What have I learned? Check the stock library parts for starters, if the PCB had been sent without the bottom solder pads they would be beyond fixing. Keep it simple (stupid), another cliche I know, but if I had been satisfied with the soldermask logo and had gone for a normal copper pour on the top layer the dremel work wouldn't need doing and the logo would be shiny in silver. Also I probably need to reach out a little more. There are plenty of folks I know that could have given the board a quick look over and saved me some time. That said, for the mistakes they look great and it gave me the excuse (if I ever needed it) to invest in the dremel drill press mount.


Riddled with errors (two errors for two components) but I think they still look rather nice!





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