Bender

[Dragonfly DIY] Modified pumpkin

We picked up a kind of neat pumpkin with a color changing LED in it. However it was just a standard Fast Fade LED of the kind that you buy on eBay (in fact I have some in the lab that are exactly the same shift pattern) and the pattern was disliked by all as it does a lot of flashing, not so much with the fading.

I grabbed an ATTiny85 off the shelf, wired an RGB LED directly to the PWM outputs (no resistors needed because of the internal resistance of the batteries), whipped up some quick code for it, got the color shifts about where we wanted them, and threw it all on a small board that replaced the single self-flashing LED on top of the existing battery holder/switch and hot-glued it in the pumpkin again.

Here's the board pre-install and the completed thing:




Click here for the code
Colors
When shifting through RGB space, I found it better to keep a constant sum, and always keep one value zero. The constant sum keeps the overall brightness level, or does so modulo that fact that the B LED will be brighter than the R or G, so you may want a scale factor. The one value zero is to avoid pastels, which haven't looked good in the LEDs I've used. Pastels may work better for you since you're lighting an interior, and I've been doing LEDs you look directly at.

So, you've got Orange as {255,153,51}, but that's the same as {204,102,0} plus a {51,51,51} aka white.