Monday, November 30, 2015

Troubleshooting NeoPixel Problems

The NeoPixel packs a lot into a tiny package, millions of intense colors! As I developed the 24 NeoPixel ring Arduino shield I encountered a couple problems and had to learn more about the NeoPixel to solve them. I found the ring needs a very stable power supply and any jostling of the pins connecting it to the Arduino or the pins connecting to the ring were likely to reset the Arduino or cause the ring to do weird things, like become dim, flash suddenly, etc. So a couple modifications I
made to the shield were to use rubber bands to hold it fast to the Arduino and to solder the pins going into the power, ground, and data in holes on the ring.
Solder bridge causing a short
Soldering a NeoPixel ring is not easy. Reaching down in the small space between the NeoPixels pretty much guarantees you will melt more than solder. Melting the plastic at the edges of the NeoPixels was not the problem I thought it would be, though. The problem came from solder bridging from a pin in a hole over to a foot of a NeoPixel. In the picture you can see this is probably happening, and is causing a short that is forcing my laptop to disable the USB device because it draws too much power. To understand how this was happening I found this post very helpful. At one point I had another ring that would only light up half way around, and this explained why. If one NeoPixel is shorted some or all of those that follow will lose power, or "single point failure."
So the solder has to be removed with a solder sucker. Fortunately as long as you don't hit the NeoPixel too much with the iron the damage is fixable. The NeoPixels turn out to be pretty resilient. If your NeoPixel ring isn't lighting up as it should and you've soldered some connections, take a close look at your solder points for any bridging.

No comments :