Light Sculptures

There is an explosion of inexpensive decorative LED lighting happening.  My contribution is a device that produces shifting colour separation shadows using 1 watt LEDs.

Powering a 1 watt LED isn't something you can do directly from a MCU GPIO pin so I found a suitable driver circuit online (https://cdn.sparkfun.com/datasheets/Components/LED/femtobuck_v12.pdf) that I could base my own design from.   That design has a creative commons license and I am duely attributing the source.

This was my first iteration of the LED driver using point-to-point hand soldering.

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I built three driver boards and connected the PWM input of each to a PWM output of a Technological Arts Esduino board.   A simple program that slowly cycles the PWM duty cycles of each output produces a pleasant random colour shift.  I installed an RGB LED on an old PC chip cooler which made a convenient support for translucent objects like this candle in a bottle (the lights are too bright to look at directly).  I replaced the Esduino with a compact board that uses a Freescale S08PA8 MCU with a LIN chip as the voltage regulator.  I never did get around to networking the design using LIN.  Such is life.  I laid out both the LED driver and controller as 2 layer boards in WinQCAD and had them made in China.

My younger daugther and her husband use this piece to illuminate the wall behind a Buddha statue.

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The next iteration used a hand crafted support for individual LEDs soldered onto copper bits I had on-hand.  The spacing between the red-blue-green LEDs produces lovely colour separations in the shadows of nearby objects.  The MCU board has a single button interface that sets the speed of the colour phasing as well as an "off" state so that unplugging the AC supply is unnecessary.  I gave this piece to Norman White, a friend and a scion of electronic art.

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I liked that piece a lot and missed it after I gave it away so I made another light for my living room much like the first one but with the LEDs spread apart to produce the colour shadow separations.  Because of tight spacing I stopped trying to handsolder some of the components and built myself a solder reflow oven using an inexpensive controller kit that I bought online (Nick Sayer's Toast-R-Reflow) and an old toaster oven that I appropriated from my younger daughter (she said she didn't mind).

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A bunch of dried Lunaria Annua (Money Plant) make the ideal source for colour shadows on our living room ceiling.

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This past Christmas I built a light sculpture for my older daughter.  This light is similar to the one I built for Norm but with more hand work to the copper.  One aspect I like about this design is the protection of the LEDs if the thing gets knocked over.  Packing the 4 boards into 1" copper tubing was challenging.

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