September 5, 2014
Jellyfish Lamp - Under Construction
I am working on my latest Jellyfish lamp. During a test I learned two things:
- It had some heat dissipation problems.
- It was absolutely gorgeous.
From the start, the main problem with the Jellyfish lamp was generating enough light for it to be impressive under normal conditions. I started using more and more powerful LEDs. This lamp, however, just uses more LEDs, many more. It is powered by more than 700 RGB LEDs, with a maximum draw of about 45 Amps. In the green close up, the dots are the individual LEDs.
Using that many LEDs became feasible with the appearance of WS2812 (or NeoPixel) strips with a packing of 144 LEDs per meter. My lamp uses 12 strips at about .42 meter, or 61 LEDs per strip. The lamp is powered by a 60 Amp 5 Volt power supply and controlled by an Arduino Mega.
Originally, my lamps displayed colors by shining the LEDs at the ceramic surface. Last year, I started to enclose the light with a translucent cloth skirt. That creates the large surface that changes colors. Coupled with the large number of LEDs, I now have a lamp that can hold its own against normal lighting conditions.
LEDs are traditionally pretty cool (temperature) light. I did not anticipate any problem using a PVC pipe as the vertical structure holding the LED strips. However, the 15-45 Amp draw eventually produced enough heat to soften the PVC. After 3 hours of use, there was a noticeable bend.
I am currently throwing a new bell/top for the lamp. It will include the same vent hole patterns that I included in the base to allow cooling of the power supply. That will be a visual improvement anyway. I will also replace the PVC with a metal pipe. I think that including multiple parallel power/ground taps on each strip will reduce the heating and spread it out from the top. If needed, I can add a small fan to the interior of the support pipe.
I was hoping that this would be my final Jellyfish lamp and that I could move on to other projects (or to finish off a few more). But two things have me questioning that. First, the problems that need to be resolved will keep me with this one for a little while longer. Second, it is such a visual leap from my previous one that I have new design questions to answer.