node-omega-frekvens

Controls an IKEA FREKVENS LED cube lamp through Node.js driving an Onion Omega 2+.

Companion repo: https://github.com/atesgoral/frekvens-fjarrkontroll

Omega Setup

You'll need space to install the required packages. Extend your storage with external storage first. I used an SD card and mounted it as overlay. You'll also need more memory to be able to run npm install. I created a swap file on my SD card. Onion has great guides on doing these.

To pull this source directly onto Omega:

opkg install git git-http
git clone https://github.com/atesgoral/node-omega-frekvens.git

Install Node.js, npm, Python and node-gyp:

opkg install node node-npm python
npm install -g node-gyp
node-gyp install

Edit /etc/opkg/distfeeds.conf and uncomment the following two lines:

src/gz openwrt_base http://downloads.openwrt.org/releases/18.06-SNAPSHOT/packages/mipsel_24kc/base
src/gz openwrt_packages http://downloads.openwrt.org/releases/18.06-SNAPSHOT/packages/mipsel_24kc/packages

Install GCC + Make:

opkg install gcc make

Do this thing that I needed to also do to be able to start compiling things:

ar -rc /usr/lib/libpthread.a

Run

npm install
npm start

To tweak things, make a copy of .env.example as .env and set the following values:

• FREKVENS_CLIENT_SECRET - the secret used for identifying this client to the Glitch server as the FREKVENS cube.
• WEBSOCKET_SERVER_URL - the WebSocket server URL, e.g. "https://frekvens-fjarrkontroll.glitch.me/"
• FAKEVENS - set to true to bypass the Omega driver and enable the textmode emulator
• LOG_BUTTONS - set to true to log button events
• LOG_CLIENT - set to true to log client events
• LOG_SYSTEM - set to true to log system events
• OVERLAYS - set to true to render visual overlays:
  • The pixel at (1, 1) indicates WebSocket client reconnection attemps. It's a good thing if this pixel is not blinking.
  • The pixel at (14, 14) indicates frame drops. It's a bad thing if this pixel is lighting up.
• ROTATE - set to whole number to rotate the rendering in 90 degree turns. 1 means 90 degrees anti-clockwise, 2 means 180 degrees, -1 means 90 degrees clockwise, etc.
• FLIP - set to either "H" or "V" to flip the rendering horizontally or vertically.

Daemonize

Assuming you cloned the repo at /root/node-omega-frekvens:

ln -s /root/node-omega-frekvens/deploy/init.d.sh /etc/init.d/frekvens
/etc/init.d/frekvens enable

The service will now run on boot. Run reboot to try. Or start and stop the service with:

/etc/init.d/frekvens start
/etc/init.d/frekvens stop

Electronics

Pop open your FREKVENS (look at videos of people doing it to avoid hurting the plastic + yourself).

The wires at the back:

• Red (COM) - common wire for both switches
• Black (SW1) - yellow switch imprinted with grid symbol
• White (SW2) - red switch imprinted with power symbol
• Two thicker white wires are the +/- DC power (3.3V)

Unsolder and plop out the stock graphics controller. The connectors:

• IR - unused (but they had plans of adding an IR receiver?)
• MIC - microphone (can be seen from the outside through a tiny hole at the front)
• GND - ground
• LAK - latch
• CLK - clock
• DA - data
• EN - enable
• VCC - power (3.3V)

Onion Omeage 2+ connections:

• GND - ground & enable
• GPIO 0 (out) - data
• GPIO 1 (out) - clock
• GPIO 2 (out) - latch
• GPIO 18 (in) - black wire (SW1) + 10K Ω pulldown resistor
• GPIO 19 (in) - white wire (SW2) + 10K Ω pulldown resistor
• 3.3V - red wire (COM)

Notes:

• Didn't use FREKVENS's own power (neither the VCC nor the white DC wires) to power the Omega. I used an expansion dock powered with a USB cable (which goes through a destroyed version of one of the screw holes at the back). The USB cable gives me the safety net of a serial connection in case WiFi goes AWOL.
• Didn't use the mic.

Communication with the LED controller board

There is a matrix of 16 x 16 = 256 pixels. The pixels are scanned in a special manner. Split the matrix in two 8 x 16 halves. Scan first half top to bottom and then scan second half top to bottom, while scanning each of the 8 pixel rows left to right. Like so:

1------> 17----->
2------> 18----->
3------> 19----->
4------> 20----->
5------> 21----->
6------> 22----->
7------> 23----->
8------> 24----->
9------> 25----->
10-----> 26----->
11-----> 27----->
12-----> 28----->
13-----> 29----->
14-----> 30----->
15-----> 31----->
16-----> 32----->

For each pixel:

1. Set data (DA) high/low based on pixel value
2. Toggle clock (CLK) high and then low

Once all pixels are done, toggle latch (LAK) high and then low.

I didn't have to add any additional delays between the toggling. Things seems to work when you're driving the LED controller at full speed.

Credits

• Includes lib/frekvens/lib/fastgpio from https://github.com/OnionIoT/fast-gpio by @OnionIoT
• @eightlines for info on the graphics memory layout + controller board communication and his own implementation
• @unframework for kicking off the hardware hacking with me and getting an Arduino prototype going

License

MIT, except content in the lib folder GPLv3.