Dependencies

Loading hardware objects

There’s a basic launcher script, e.g. two_button.py. This script should only contain the business logic, and high level interface.

Hardware itself is enabled through the ini file. For example:

[pins]
on_button = Button:11:38

This enables the code in the launcher script to load some number of devices to use as an enabling button (the name is arbitrary):

class Dispatcher(BaseDispatcher):
  def __init__(self, config):
    super(Dispatcher, self).__init__(config)
    ...
    self.load_config_object('on_button', on_down=self.on_button_down)

Then whenever necessary, you can call

self.on_button.blink()
# or
self.on_button.off()

to change its light, or in

def on_button_down(self, source):
  print "Button pressed"

Multiple hardware for one action

Simple! It’s a list.

[pins]
enable_output = Relay:ActiveHigh:29
# or
enable_output = Relay:ActiveHigh:29, Relay:ActiveHigh:31

Threading model

Each hardware device (button, buzzer, etc) may start its own thread, but events are delivered in one main thread for ease of programming.

Running on boot

The simplest way is adding an @reboot cd /path/to/source; python two_button.py to crontab -e. You can also make a systemd unit, if your distro supports that.

More reading

See qa.py or two_button.py for examples of how this can be used.