Almost 500 stars were constructed individually and operated under the power of a coin cell for close to a month. Each star was adhered to the surface of the dome with adhesive, in my case, hot glue. Pay close attention to the threshold voltage across the LEDs, as reasonably priced bulk coin cells only come as high as 3V.
If using fabric in the future consider sewing/gluing in conductive thread. We did a small area running parallel lines an inch apart which were then alternatively hooked up to + and - to them at the edge. Treat like a flexible breadboard then to power stuff on the fabric with short hookup wires.
Works well for small areas, not sure about a 20ft wall though.
That's a great idea! I'd have preferred to do something like that, except the fabric was already up prior to creating the lights. I'll keep this in mind for next time!
They did twinkle, though there was definitely room for improvement in the twinkling behavior. I'll post schematics when I'm not on a mobile device. Thanks for the reminder!
I'm considering redoing the whole project in fiber optics. This quantity of cell batteries proves a bit expensive for a consumable cost each time we set up the dome. The main drive behind batteries was that we didn't have much time, and we didn't want to worry about how we were going to distribute power over the whole thing.
The next installation is going to be a wall indoors as a particle effect, so thankfully I won't have to mount things on a 20ft high concave fabric surface.
I didn't see any info on mAh for the batteries you used. But when you mentioned consumables I wondered if you could possibly get away with a super-cap setup? I envision an inductive charging system that puts a stick with a coil on the end of it... like lighting oil lamps of yore, someone would go around each evening and juice up the caps. Whimsical, isn't it?
In response to Mike, because nested replies aren't a thing yet.
The more I think about your idea, the more I like it. I'll have to look into doing that for future installations. I can probably even modify my existing boards, rather than having to buy new ones, which is a huge plus.
Works well for small areas, not sure about a 20ft wall though.