LightScytheJS is a control software for a LED stripe light painting tool written entirely in javascript/node.js.
The basic idea for this tool was developed by The Mechatronics Guy and brought to life with the LightScythe project which in turn took inspiration from Immaterials: light painting WiFi.
More 30C3 images on flickriver, by Universalist on tumblr an on Martin Voigt's Photo Blog.
So the LightScyteJS is more an evolution of an existing concept than a new idea. It was intended to be an excercise to get accostumed to node.js using the Cubieboard platform and improved the original in some aspects:
- Pure node.js makes the code easy to understand and to maintain for people not used to microcontroller platforms.
- A web interface utilizing express and jQueryMobile provides convenient and fine tuned control of the device in the field.
- Images to be displayed need no special preparation and are pre-processed on the device using gm and GraphicsMagick.
The hardware consists of
- a cubieboard (raspberry Pi should work as well)
- a WS2801 LED strip
- an USB wifi dongle
- a 2S LiPo and 5V BEC for power supply
We use setcap:
sudo apt-get install libcap2-bin
sudo setcap 'cap_net_bind_service=+ep' `which node`
If the node process runs as non-root (recommended), the GPIO pins have to be exported prior to starting the process: sudo su -c 'echo 1 > /sys/class/gpio/export;echo 2 > /sys/class/gpio/export'