In my last post, Batteries, batteries, batteries! (Or, how do I power this thing!?) I mentioned the power and flexibility of Lithium Polymer (LiPo) batteries for your projects, but said I mentioned that I hadn’t started to work with them.
For an upcoming project, using an Arduino Gemma (which I talked about in my post about “But the Arduino is too big for my project!“) I decided to use a LiPo battery, since the Gemma conveniently has a JST battery connector on it.
As a test, I connected a NeoPixel Stick — another awesome piece of kit from Adafruit, to the Gemma. The Neopixel Stick, like all Adafruit’s Neopixels, is a string (in this case, a stick) of RGB LEDs with a built-in color controller. The Stick is 8 of these LEDs on a rigid circuitboard. Each LED in the stick is really three sub-LEDs, one in Red, Green, and Blue (hence RGB). With these three sub-LEDs, you can make almost any color you can imagine. Because of the built-in color controller, you only need a single data pin (besides the two normal power connections) to control an entire group of LEDs!
Note that if you are interested in NeoPixels (I learned about them from my friend Jeff McDaniel, who did the Teslapunk panel at Phoenix Comiccon) you should read Adafruit’s entire Uberguide, here. I’d call them a medium difficulty item, as there are some power requirements to be aware of…in short, the individual pins on an Arduino can’t handle the amperage for many of these LEDs, so you need to directly wire them to power.
To test the LEDs, I connected the appropriate pads on the Stick to positive, negative, and D1 (digital pin 1) on the Gemma. I ran a “Larson Scanner” test — this is named after Glen Larson, who was the producer of the old Knight Rider and Battlestar Galactica TV shows, which both featured a red moving LED light (on KITT the car’s front bumper and the “eye” of the Cyclons). This test basically chased from one LED to another and altered the colors each time.
Here’s a demo video of the setup:
The Neopixel Stick is held in the grip, the little blue breadboard in the middle is just linking the soldered wiring to the alligator clips connected to the tiny Gemma board. Notice the silver LiPo battery pack powering the Gemma!
I’ll mention the Neopixels are really bright, wow!
The LiPo battery pack is 850ma, and cost around $8. So, take a guess at how long it ran that Neopixel test?
Over 30 hours, wow!
I think I’ll be using LiPo more in my projects!