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Hacking-Guide

Architecture

The firmware for the alarmclock is implemented in python. The main program is the script /usr/local/sbin/nerd-alarmclock.py, which is started by the systemd-service defined in /etc/systemd/system/nerd-alarmclock.service.

The main script does not contain much logic. It mainly creates and loads various object taking care of the hardware. All classes are submodules of the nclock-module. During installation, the code is copied to /usr/local/lib/python2.7/site-packages/nclock.

Logically, the software follows the MVC paradigm. The model is implemented in the class Settings. The LedController and DisplayController are views, and the KeyboardThread and BotThread are the controllers.

Objects don't call methods directly, they only change attributes in the Settings. They also register callbacks for attribut-changes there and are called when the registered attribute changes.

Implementing new Hardware

As an example, we will walk through the implementation of a new hardware component, which controlls a wall-plug. For this component we will need a controller that acts as a alarm-provider (since we want to turn on the plug on an alarm event).

So you need to implement and change the following code:

  1. Create a class PlugController in /usr/local/lib/python2.7/site-packages/nclock/PlugController.py
  2. Import the sub-module in /usr/local/lib/python2.7/site-packages/nclock/__init__.py
  3. Instantiate the PlugController in /usr/local/sbin/nerd-alarmclock.py

To act as an alarm-provider, the class must implement and register a method which will provide an alarm-thread. You are free to choose a suitable name for this method, but by convention it is named get_alarm. You can use an existing controller (e.g. SoundController) as a template.

The get_alarm-method will return either None (no alarm configured), or a thread. The thread in this case would just turn on the wall-plug.

Since this is a new component, there is no UI to configure the plug-alarm. You either have to edit the settings.json file manually, or you have to extend the BotThread or WebThread.