Jana Marie Hemsing's LÄMP-Panel Is an Infinitely-Tweakable LED Spot with RGBY and Two White Channels
Built with Zigbee connectivity for smart home integration, these flat-panel LED spots mix more than the usual number of colors.
Electronics and embedded engineer Jana Marie Hemsing has designed a custom set of LED spotlights with additional color channels over the usual red, green, blue, and white, allowing for finer-grained control over their color rendering index (CRI): the LÄMP-Panel.
"Being in need for some colorful light for my room I designed some RGBY + W [Red, Green, Blue, Yellow plus White] spots a while ago. They feature Zigbee and fit right into my existing ecosystem (Philips Hue)," Hemsing writes of the flat-panel lamps. "I love the extra yellow channel, this was super important to me, I have huge aversion for mixed yellow."
The hexagonal lamps are built around SK6812 surface-mount LEDs, but in an unusual mix. A typical single-color LED lamp will use warm-white or cold-white LEDs, sometimes mixing the two to allow for finer control over color temperature; a full-color lamp will either use red, green, and blue LEDs or add a white channel to the mix to make up for the inability to mix true white with RGB LEDs. Hemsing's panels, though, include four colors - red, green, blue, and yellow — plus two white channels.
"The 4 color + 2 white channels can be [achieved] by combining RGB and WWCWA (warm-white, cold-white, amber) SK6812 LEDs," Hemsing explains. "This also allows increasing the CRI [Color Rendering Index, a measurement of how far away artificially-lit objects' perceived color is from their appearance under direct natural sunlight] by e.g. adding green to the white channels."
The project comes as a spin-off from Hemsing's LÄMP-Prism, a larger decorative lamp built from nine interlocking PCBs and 291 LEDs; the LÄMP-Panel, by contrast, is a simpler affair, built around an Espressif ESP32 microcontroller and a Chengdu Ebyte E75-2G4M20S Zigbee transceiver.
Hemsing has published the design files and source code for the project on GitHub under the CERN Open Hardware License Version 2 — Strongly Reciprocal.