Adam — Fri, 15/01/2010 - 4:51pm
I'm working on a simple lighting display for a friend's night club event. It's based on 9 Aerpro 'neon' under car lights and will be sequenced by an Arduino.
I've decided that this would be a good a time as any to design my own Arduino shield and to start having a serious attempt at using gEDA.
All I need is a transistor, a resistor and a header to control each light, all of which were a few bucks at my local Jaycar. I've decided to put 12 copies on the board incase we want to expand. 12 is convenient because: a) that's how many digital pins aren't reserved for other uses on the Arduino b) I still have all 6 analog pins if I need more IO lines and c) thats how many edges a cube has. :)
This is the first time I've seriously tried to design a PCB and I'm not very good at it. I'm stubbornly into open source and have shunned Eagle for the gEDA suite. This has proven to be problematic because very few people in the Arduino world appear to be using gEDA. I spent a very long time trying to find a layout for pcb which had the Arduino headers and mounting holes in the right places. I ended up having to lay it out myself using a mechanical drawing of the Arduino done by The errant engineer as a reference. I also got a lot of help from Getting Started With [gEDA] PCB by DJ Delorie. I've pulled a few nice footprint deffinitions from this library of gEDA footprints, most notably the TO-92 for the transistors.
I'll be posting the layout for review in the next few days and hopefully I can get a prototype milled soon, that's if the mill can handle the TO-92's pitch. Otherwise I'll just break them out to a 100mil pitch. Once I've tested the layout I'll post files and docs on using the gEDA tools to build Arduino shields, a document that the internet is sorely lacking.