Here is a picture I took before throwing them on the roof:
The setup used wire nuts since it was a 1-year 1-off type build. I already planned on using the E681 next year and if I couldn't get my controller working in time, planned on using the E681 using "groups" to get the "dumb rgb strip" my sequencing was all done for, but I was able to get everything working.
Basically the controller consists of a little RS485 break-out on perf-board which takes in RS485 data (renard protocol) and feeds it at TTL to an arduino clone that I picked up on eBay for under $10. The "firmware" I wrote for it is very simple and basically takes 4 channels of data (hard coded location in the renard stream, similar to the renard start-address firmware) and spits out GECE commands to the lights from one of the pins. At initialization time I assign all bulbs address 0 and only send one command to the GECEs per vixen event update, getting the dumb rgb strip effect.
I had a couple of issues with the design:
First was a flicker problem when controlling the GECEs with my original code. Turns out it was because the arduino serial library's interrupts were interfering with the timing of my writing to the GECEs. Based on the timing of my event updates, writing to GECEs, reading data, etc. I was able to "hack" around it by simply disabling interrupts before sending my GECE data so the serial library didn't affect my timing, then I would immediately re-enable them to resume reading data. There's a thread when I asked for help
here.
The other issue I had was not having foresight. I had about 5 sets worth of GECEs cut into 7 segments for portions of my roofline. I had 3 controllers total. One running 3 strings (3 output pins of the arduino clone) and 2 running 2 strings each. I planned on using only 3 of the GECE power bricks, one for each controller. The arduino clone I was using didn't have power regulation, only input for a clean 5V source. I knew the 5.6V that the GECE controller was too much, so I threw a 7805 regulator on to "fix" that high voltage for me. Once everything was up, I had problems that manifested itself in white blinking GECEs. Long story short, it was a brown-out of the µC. I originally mis-diagnosed it as not enough current available from the 3 power bricks, bought a beefy 7.5V supply (adjusted to ~6.75V) which still didn't fix my problem. Turns out I couldn't use a regular 7805 (which I should have known from reading up on the renard controllers), I needed an LDO 5V regulator. I measured the voltage at the µC and it was about 4V with nothing going on, and as soon as the GECEs turned white, the voltage drop from them pulling a bit of current from the supply resulted in about 3V to the arduino clone and a brown-out reset. Once the LDO regulator was swapped in, I haven't had any problems.
