Random experiments, circuits, code, rapid prototyping examples, sometimes things to buy, and occasionally tunes by Tod E. Kurt.
Yay BlinkMs!
BlinkM is a smart LED. Imagine an LED with a tiny computer inside, one that can be any color and have a life of its own. You can buy them now from one of our global distributors.
SketchUp is pretty great, but I found a problem with it if you’re trying to make accurate to-scale electronic parts: it won’t create surfaces with an area of <1mm. Took me a while to figure that out. The solution is to make a 10x or 100x size version and then do a scale by 0.1 or 0.01 when you’re done.
BlinkMs are a lot of fun by themselves, but they’re also little network devices, each having its own address on an I2C network. Here’s where I think BlinkM can really shine since it makes controlling multiple RGB LEDs pretty easy. For Maker Faire, I wanted to show off this facet by having a single Arduino control a dozen or so BlinkMs on a single I2C bus. The result is shown in the little video below.
Want to hook up a Wii Nunchuck to an Arduino but don’t want to cut up the cord on your Nunchuck? Yeah me too. So I made some of these:
It’s a small PCB that adapts the Wii Nunchuck connector to standard 4-pin header. I call it the “wiichuck adapter”. It plugs directly into the Arduino, no wiring necessary. You can get one too for $4.
This is a BlinkM:
BlinkMs are “smart LEDs”, a type of smart interface component. A BlinkM consists of an ultrabirght RGB LED backed with a microcontroller with built-in knowledge about 24-bit color spaces, color fading, and color pattern generation. All in a package 0.6” wide. You talk to it over I2C, a serial protocol spoken by many different things. (Arduino speaks it, as do Basic Stamps, and your PC) And you can have over 100 BlinkMs on the same serial bus, each individually addressable. Here’s how they can hook up to an Arduino:
BlinkMs are available from SparkFun (US) and Little Bird Electronics (AU). It’s hard to show in just static pictures how fun and easy it is to play with BlinkMs, so here’s a few quick video guides.
A demonstration of one of the example Arduino sketches “BlinkMTester”, which lets you exercise a BlinkM by typing simple commands to the Arduino.
Exampe Code
There are a couple of examples of how to talk to BlinkMs all zipped up in BlinkM_Examples.zip. You can also peruse them unzipped if you like. The examples are predominately for Arduino currently, but any I2C master will work. Some of the examples so far:
BlinkMCommunicator
A simple serial-to-i2c gateway for PC controlling of BlinkM (for instance via Processing or the BlinkM Sequencer)
BlinkMTester
A general tool to play with a single BlinkM
BlinkMMulti
An example showing how to communicate with multiple BlinkMs
BlinkMScriptWriter
A demonstration of how to write BlinkM light scripts with Arduino
BlinkMChuck
Control the hue & brightness of a BlinkM with a Wii Nunchuck
More examples will be added periodically.
For the Arduino examples, a convenience library called BlinkM_funcs.h has been created. Just drop this .h file into your sketch folder and call the functions to start playing with BlinkM.
The complete list of functions is below, though you’ll probably only use a few of them for a particular project.
With BlinkMs available for purchase soon, I figured it would be neat to show what a large collection of them can do. BlinkMs were created from my desire to have a “smart LED” that did its own tri-color PWM. I didn’t want to build a real-time system to control the PWM of several hundred RGB LEDs. And existing LED controllers didn’t meet my needs. I wanted something that knew a bit about color and color patterns and could be networked together into clusters. Thus BlinkM. A single BlinkM is fun, but the real utility is seen when you have several of them on the same I2C network.
Below are two movies of the lighting system in WineM, our smart RFID winerack. Each place a bottle goes contains a essentially BlinkM and RFID reader controlled via an I2C master.
WineM prototype at NextFest
This video shows WineM in use. A handheld web device allows one to select and display different facets of the wine collection. In the video, first all wines are shown, colored by varietal, then Cabernet wines are selected. Within the Cabernets, color them by year. Select 2002 as the year and only the 2002 Cabernets are shown. Then color those by price. Finally, select the 2002 cabernets that are between $20-$30. You’re left with the perfect wine for tonight’s meal. Also shown is the visual indication when bottles are added or removed.
WineM prototype light tests
This is just a light show using the WineM lights. It was taken right after I had assembled and installed everything in the rack. Apologies for the exposure fluctuations.
For a bit more detail on the WineM prototype hardware, see this post.