I really don’t like hanging or taking down Christmas lights. I generally do the bare minimum my wife requires to get through the holidays. I HAVE always been intrigued with the computer controlled lighting displays that are synced to music. Last year I got into a fun partnership with one of my neighbors. He wanted to do the whole music shebang, but didn’t know how to do the hardware side of the equation. Mmmm.. symbiotic relationship.
Last years’ system was a 12 channel deal controlled by a basic arduino. Worked well enough, built on perfboard and stuffed into a 2-gang junction box. Downsides were it was not engineered well at all, with the 5v logic intermixed with the 110v ac. It also required a lot of extension cords as all 12 channels/outlets were combined at the same location (in his garage).
So, we are at it again this year. The objectives are:
- increase to 30 channels (arduino mega)
- hub/spoke design.. with centralized control and 6-channel remote boards to minimize extension cord usage
- add LEDs to show when channels are on/off for easier programming/debugging
- safer design.. with better isolation between logic and 110v. also include little things like fusing on board.
- waterproof enclosures as we are approaching this as a modular multi-year initiative
So with that in mind, I first created one of the satellite boards. I designed this in eagle, with a goal of keeping it a single-sided board for easy machining. The initial trial board machined out well (see previous posts showing generation of gcode from eagle-cad).
First run was pretty good, and soldered up into a usable board. I did have to hand-dremel a joined trace. Improvements identified were:
- Increase the amount of cnc routing around the traces to improve isolation
- fix the 110v connector pin sizing. I had them at .1 and they are really .2, so my screw terminal connector wont fit
- Add a fuse which I forgot to add
- Increase trace size where possible. Mid-trace holes sometimes cut the whole trace, so had to bridge with solder.
Did solder up ok into a usable board though:
After a few eagle cad changes and some modifications to the cnc gcode generator you can see the a/b comparison of the boards. With the original run on the right, and the new one of the left. Machine time takes about 30 minutes/board. Using a 60 degree v-carve bit… probably not the best tool for the job. If you have recommendations on bits please let me know.