Sound to lights interface

Like the circle drawing robot Bowed, this one went to Venice Biennale in Venice, as part of Jaša’s Utter show in the Slovenian pavilion. Utter was sponsored by Arcadia Lightwear, providing lights for the installation. One of the ideas was to make the lights to follow the sound, so that poetry and music and everything would translate to a visual effect. I do not know if the problem was technical, financial, project management related, or what, but for some reason they could not provide a solution for that. So, the next one to call for help was me. This article is about the solution.

After some hard struggling with the idea of building a dimmer circuit from scratch using triacs, I figured out that I was to get it working at all, I had to start from something a bit more ready made. Research very quickly turned up the dmx protocol. It looked like a good fit because dimmers receiving it were reasonably priced. Also the protocol was simple enough for hacking around, and indeed DmxSimple library had already a solution suitable for avr, only pending removal of stuff specific to Arduino, which I did not use for this project.

This project was interesting, since I had not worked with uart before. It was a magical experience to first read the [description of dmx protocol][dmx- desc] talking about microsecond signals, wire something together and see it work on the first try. Taking that I did not use an oscilloscope or any other tools that could see those high frequency signals being passed around, I managed to impress myself b getting the thing to work as quickly as I did. We owe so much to people who take their time to write down how things exactly work, and who make all the parts and components available for us!

Sources and some technical documentation is available in the project Github repository.

The biennale lasted for six months. I consider half a year of constant use a tough reliability requirement, so I was not so surprised to hear about a problem half way through. Luckily, it was one that was solvable without me having to go to Venice:

Dear Otto,

I followed all your steps, doubled check before with Junzi, he’s gone now, his turn for some time off…to make sure that it was not due to some audio output … once all of that was cleared I started following your instructions…started with the dimmer, and all looked fine there was exactly as you described…so I did not change anything…I followed the cables, if by chance anything got unplugged…all good there too… which led me to the black box…there I started unplugging, plugging back in…followed the cables, but nothing happened not even a glimpse of light on the three bulbs, then the desperation leaded me to your last instruction, I’ve shaken the box…nada, then as the last desperate act I slapped it and put it back to where it was, to my biggest surprise and immense kick of satisfaction, when I got up and turned determined to go for a smoke to cool down, the bulbs where on!!!

so the old kicking of the machines of of mere desperation still works!!!

ha ha

take care, and thank you for this…will keep you updated…for the rest it is all running perfectly… you, ales gut?