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RGBulb. Richard Whitney. Background . Proliferation of LED-based lightbulbs Monochrome Overpriced …But they do last for ~100,000 hours, are extremely efficient, and aren’t a fire hazard $0.80 for a year of 12-hour days. Design Requirements. Must look like light bulb
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RGBulb Richard Whitney
Background • Proliferation of LED-based lightbulbs • Monochrome • Overpriced • …But they do last for ~100,000 hours, are extremely efficient, and aren’t a fire hazard • $0.80 for a year of 12-hour days
Design Requirements • Must look like light bulb • Screw into socket, no external components (transformers, etc) • Easy to use • Can be constructed in two days (of continuous backbreaking work) • Be safe
Implementation (Electrical) • Red, green, and blue light-emitting diodes • Atmel AVR (Tiny26) • 3 n-MOSFETs • 3 potentiometers (50K ohm) • Various resistors
Implementation (Software) • AVR reads voltages off of potentiometers via ADC, produces 0-255 integer • Continuous “for” loop, 255 times between breaks • R, G, B channels turned off after relative time • Results in pulse-width modulation
Implementation (Hardware) • Small transformer from RadioShack • Disassembled fluorescent socket light • Vacuform over incandescent bulb
Results • Worked great on protoboard • Construction went well • Migration to breadboard had difficulties • Current status: some kind of glitch (short) holding G and B potentiometer pins high (possibly)
Future Development • Fix circuit • Potential for using AVR to expand capabilities • -Remote control • -Timer • -Contextual response
What I Did With My Weekend • dx/dt