LED Mood Cube
Everyone has seen those simple, heat-activated, 60's faux pas mood rings that change colour depending on your "mood". Ever wanted that same funky effect to light up your 'pad'? I didn't think so. But a colour changing mood light can be fun; and when it incorporates LEDs, circuitry and the Arduino microcontroller, what could be better?
You will need:
- 1x Arduino Microcontroller (or similar device)
- 1x Arduino Protoshield or a Breadboard of some sort
- 1 each of Red, Green and Blue LEDs. Preferable bright models (>=1000mcd)
- 3x 330 Ohm 5% resistors (Orange-Orange-Brown-Gold)
- 6x or so jumper cables for use with the breadboard
- One power source; I used the 9V battery pack for the Arduino
Building it
Assembling the device is about as simple as it gets. Basically, we're connecting each of the red, green and blue LEDs to one of the pulse-width-modulation capable pins on the Arduino. In my project, I used pins 3, 5, and 6 for red, green and blue respectively. Each of the anode (positive/long) ends of the LED is linked to a 330? 5% (330 Ohm or Orange-Orage-Brown-Gold) resistor before
After the LEDs and resistor pairs are in place, simply run a jumper cable from pins 3, 5, and 6 for red, green and blue respectively. These jumpers will provide power to the corresponding LEDs at a modulating square wave of varying frequency. Basically, the pin goes HIGH for a certain number of milliseconds and then goes low for a certain number of milliseconds. Proportionally, the more time the pin spends HIGH, the closer the LED is to full brightness. This is reflected in the Arduino code as a value of 0-255 where 255 is full brightness. The project code for this project is available at the bottom of the page along with the GNU/GPL license.
Once the Arduino setup is comple, the last thing to do is to build a light diffuser. If you were to run the device now, it would be obvious to tell where one colour ends and the next begins. With a simple light diffuser, the light given off by the LEDs is mixed into a solid shade of whatever colour the primary R/G/B LEDs create. To make your own simple (and free) light diffuser box, print out the following pattern on a piece of paper:
Click to enlarge
Cut out the shape and the shaded box; this will be where the LEDs stick into the box. Fold the box, gluing the sides together via the tabs. Before you glue the last side, stick a couple sheets of tissue paper inside so that they cover the entire inside of the surface of the cube and are fluffy enough so that the light will diffuse through the material evenly. Once you glue all the sides together, you have your diffuser box!
Sliding the protruding LEDs into the hole you cut, in the middle of the tissue paper filling, place the box on the Arduino setup. Then, power it on!
