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Help getting started with programming on the Onion

  • I am a total newbie at the Onion AND at Linux. Are there any tutorials and/or videos available to show how to write, store, and run a program on this nifty device? I'm initially interested in reading from and/or writing to the GPIO pins. I have some familiarity with Python, but would also like to know how to program the Onion in Ruby. Thanks for ANY help y'all can provide.

  • @Jeff-Verive , not much, but I've been writing down a cheat-sheet of my own exploration:

    • Connect at 115200 bps with TeraTerm

    • To setup wifi,
      run wifisetup command
      wifisetup -checkconnection
      run ifconfig to verify

    • Web interface

    • Upgrade F/W
      run oupgrade -check
      See https://onion.freshdesk.com/support/solutions/articles/6000069919-how-do-i-update-the-firmware-
      Upgrading the firmware will delete/overwrite all of the files that are not in /etc or /usr

    • Most built-in linux commands redirect to /bin/busybox (multi-call binary)

    • Update packages list
      opkg update
      opkg list

    • Change Dock RGB LED
      expled FF0000 -> red
      expled 00FF00 -> green
      expled 0000FF -> blue
      expled 00FFFF -> cyan
      expled FFFF00 -> yellow
      expled FF00FF -> purple

      This actually drives pwm GPIO on I/O pins 15,16,17:
      fast-gpio pwm 17 200 0
      fast-gpio pwm 16 200 100
      fast-gpio pwm 15 200 0

      To flash slowly:
      fast-gpio pwm 15 2 80 -> blue
      fast-gpio pwm 16 2 80 -> green
      fast-gpio pwm 17 2 80 -> red

    • OLED expansion
      Use oled-exp command
      oled-exp -i power on
      oled-exp write Hello
      oled-exp -c power on cursor 3,6 write "zoulou was here"
      oled-exp scroll diagonal-right

    • Run in background
      To send to background, use Ctrl-z
      bg command to resume
      jobs command to list
      fg %job_id to bring back to front
      Or append & at the end of command to put in background directly

    • Mosquitto setup
      opkg install mosquitto
      opkg install mosquitto-client
      [opkg install libmosquitto] -> done by install mosquitto-client

      subscribe in background:
      mosquitto_sub -v -t /test/#&
      publish message:
      mosquitto_pub -m 'Hello' -t /test/pub

    • Node.js setup
      nodejs - 0.1-1 - Event-driven I/O server-side JavaScript environment based on V8
      reports v0.10.5 (history says it is 2013-04-26), see https://nodejs.org/en/download/releases/

      /usr/bin/node (or just node, since /usr/bin is in the path)

      Test Node, copy this to hello.js
      var http = require("http");
      http.createServer(function (req, res) {
      res.writeHead(200, {"Content-Type": "text/plain"});
      res.end("Hello World\n");
      Run as node hello.js&

      npm is supposed to be standard with node.js since 0.6.3, should have npm 1.2.18, not sure how to get it...

  • Hi @Jeff-Verive, you can install ruby with these simply commands:

    opkg update
    opkg install ruby

    However, we are still working on wrappers for the scripting languages. Currently we have finished the majority of the expansion drivers for python, and are working on wrappers for javascript and PHP.

    Since you are already familiar with python, you can start writing program with the Omega by taking a look at these tutorials on our libraries: https://wiki.onion.io/pages/Tutorials/Libraries/. There is a section on how to use our Python library in each article.

    Please let me know if it helps.

  • I put that in better form on my blog here: link text

  • Hi @Greg-Ware, we are still working on the npm because with many modules it requires the compilation of C/C++ code into binary. The Omega doesn't have enough computational resource to complete the compile itself, so we are working on a way to pre-compile some of the commonly used npm packages so that we can simply fetch it from a server during npm install.

    Also your cheatsheet is super useful! Do you mind if we post it on the Wiki?


  • Hey thanks for tips šŸ˜‰

    [post edited]
    to install node.js

    • opkg update
    • opkg install nodejs

    Next step a piratebox ^^

  • Hi @Vincent-Bonnefille, yeah, you can install node without npm. You simply need to run the following commands:

    opkg update
    opkg install node

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