RGB disco!

The RGBController.js file in this package, when run, will attempt to find three directories under the current working directory (pwd): red, green and blue, and attempt to use them as PWM controls. It will then present you with an HTML/JS-based command interface over HTTP so that you can set your own duty cycle, i.e. control lighting brightness interactively.

Running

The script assumes that files ./red, ./green and ./blue are symlinks to the respective GPIO PWM output channels.

For example, on the Intel Galileo, you need to export the appropriate PWM channels as per http://www.malinov.com/Home/sergey-s-blog/intelgalileo-programminggpiofromlinux

In my case, the red PWM output was channel 4, the green - channel 7 and the red - channel 1 (corresponding to Galileo pins 11, 10 and 9 respectively).

Thus, I first had to export the PWM channels from pwmchip0 to enable userspace visibility:

# echo -n 1 >/sys/class/pwm/pwmchip0/export
# echo -n 4 >/sys/class/pwm/pwmchip0/export
# echo -n 7 >/sys/class/pwm/pwmchip0/export

Then, I created the symlinks to the newly-exported channels in the directory that I was going to run RGBController.js in:

# ln -s /sys/class/pwm/pwmchip0/pwm4 red
# ln -s /sys/class/pwm/pwmchip0/pwm7 green
# ln -s /sys/class/pwm/pwmchip0/pwm1 blue

Finally, I ran the script (having made sure all dependencies were in place via npm install):

# node RGBController.js
Listening on port 9844

Apparently, all went well and my little script opened an HTTP management interface on the displayed port!

Short-term improvements

• Separate the Web interface and the runner from the RGBController logic
• Implement another control/status interface (AMQP? STOMP?)
• Publish color changes to the client; synchronize values with all clients for consistency
• Document the reference MOSFET-based circuit design & pin connections to the Galileo

Roadmap

Yeah, well... any ideas?

License

MIT