Tuesday, June 7, 2016

Down to the Wire

Here we see the electronic components of a single pod. 576 LEDs, two 20 amp/100 watt 12 volt -> 5 volt converters, a bunch of wire and connectors, and a microcontroller...  In this case, an Arduino Uno. The finished work for Sculpturefest will include four pods for a total of 2,304 LEDs.  One microcontroller will direct all four pods.

In addition to the electronics, each pod will be comprised of metal mesh, four 3D-printed plastic spacers, and 640 square inches of clear woven diffusers repurposed from two-liter plastic bottles.
As you might notice, this portion of lights, those that are lit, are drawing less than an amp of 12v power but are overdriving my phone's camera. 

My prosumer bench power supply maxes out at 4.5 amps at which point the LEDs are incredibly bright. The LEDs and the DC converters (seen in the foreground) still have a lot of headroom as evidenced by flickering when I try for full white. Unfortunately, I can't coax more power from my bench supply so I can't fully drive these LED strips.


Once I have the final power supply in place, I'll be able to signal directly to extraterrestrial cultures.

These bright lights won't be used at Woodstock's Sculpturefest, opening next month. There, the lights should be constrained; not draw attention from other works but be apparent to viewers of the piece itself as part of the aspect of the work.  The electronics include a dimmer on the outside of the device to facilitate balance.

There are other venues where the ability to brighten things up might be more appropriate and I expect to take this work to those places.

At each venue the brightness will have an impact on the surroundings so it is possible that the dimmer will be placed in such a way that it will be operable by persons observing the piece, to allow the viewer to adjust the brightness to complement their experience.

I have about 20 days to get this piece installed in Woodstock. At this point, I've completed prototypes of all of the major physical, electronic, and software components. The overall design is done; almost all of the ingredients have been acquired or are on their way. Coming up is a period of frenzied art production and installation.

There are still a few mundane structural items that need to be thought through and designed... But those will come in time.

I still have two significant technical challenges that need to be successfully addressed to support the design-specified number of LEDs.  Tomorrow night I'll be working on moving the deployment platform for LED control from the Arduino Uno to the Teensy 3.2. The Teensy supposedly works in the Arduino ecosystem. After that, I'll be migrating the LED hardware from APA102C, DotStar, to WS2812, NeoPixel. Hopefully that will be nearly seamless, too.  Once those two tasks are completed I will be able to run all 2,304 lamps from a single microcontroller.

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