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So far in this series, we’ve shrimped our 11 year old recovered Compaq Presario 700 laptop with a 64 pixel HL1606 RGB LED display, and attached it to our desktop’s music player as a graphic equalizer.

So far; however, we’ve hardly used color at all, so it doesn’t look nearly as nice as the color_swirl example provided by the original Adafruit library.

A simple modification we can make is to introduce a random walk in the colors, which we paint to each pixel when it’s on. If we place the following code at the top of the loop() function, it will cause random numbers to be added to each of the red, green and blue components of the active color in our graphic equalizer.

The use of constrain() stops the random walk from wandering outside the conventional range. Try changing the walk value to make the colors change more or less rapidly.

Here’s the final demo.

Much more complex behaviours are of course possible. For example, why not make each equalizer column into a rainbow, graduate it vertically from green to red, or use a moving average to have the equalizer remember the general trend and maximum of recent values in each band, then leave that average or maximum showing as a trace of a different color.

Graphic equalizers are also only one example of the kinds of information that can now be displayed on our HL1606-shrimped laptop. It’s feasible to use low-resolution pixel fonts to write and scroll text to the screen, very simple icons can be shown on it. You can probably hypnotize your boss with it and ask for a pay rise. Maybe experiment with the cat first.

Whatever you do with it, you’ve recovered a machine that would otherwise be on the scrapheap, and you’ve given it a ticket to the future.

Safari Books Online has the content you need

These books in Safari Books Online will help you enhance your Arduino project:

Getting Started with Arduino gives you lots of ideas for Arduino projects and helps you get started with them right away. From getting organized to putting the final touches on your prototype, all the information you need is right in the book.
Arduino Cookbook, 2nd Edition helps you create your own toys, remote controllers, alarms, detectors, robots, and many other projects with the Arduino device.
In Beginning Arduino teaches by using an amazing set of 50 cool projects. You’ll progress from a complete beginner regarding Arduino programming and electronics knowledge to intermediate skills and the confidence to create your own amazing Arduino projects.
Building Wireless Sensor Networks helps you build a series of useful projects, including a complete Arduino- and XBee-powered wireless network that delivers remotely-sensed data.
Arduino Robotics will show you how to use your Arduino to control a variety of different robots, while providing step-by-step instructions on the entire robot building process.
Arduino Projects to Save the World shows that it takes little more than a few tools, a few wires and sensors, an Arduino board, and a bit of gumption to build devices that lower energy bills, help you grow our own food, monitor pollution in the air and in the ground, even warn you about earth tremors.

About this author

Cefn Hoile sculpts open source hardware and software, and supports others doing the same. Drawing on ten years of experience in R&D for a multinational technology company, he works as a public domain inventor, and an innovation catalyst and architect of bespoke digital installations and prototypes. He is a founder-member of the CuriosityCollective.org digital arts group, and a regular contributor to open source projects and not-for-profits. Cefn is currently completing a PhD in Digital Innovation at Highwire, University of Lancaster, UK.

Tags: Arduino, Color, Python, shrimping,

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