Adapting the plugin to a bench

Every Raspberry has its own bench. The whole difference between two benches is held in a single file, src_raspberry/config.py: the transport, the request handling and main.py never change.

The configuration file

config.py exposes the I2C bus id, the GPIO pins and two structures describing the hardware.

Actuators — a list of dictionaries. Each actuator selects its driver with the driver field (PWM or DIGITAL, keys of ACTUATOR_DRIVER_REGISTRY):

ACTUATORS_CONFIG = [
    {
        'pin':           18,
        'title':         'Ventilateur',
        'name':          'ventilateur',
        'driver':        'PWM',        # 'PWM' or 'DIGITAL'
        'units':         '%',
        'min':           0,
        'max':           255,
        'address':       None,
        'pwm_frequency': 25000,        # PWM only
    },
]

Sensors — a dictionary keyed by I2C address. Each sensor selects its driver with the driver field (key of SENSOR_DRIVER_REGISTRY: AHT10, TMP102, EMC2101, PT-100, SIMULE); the default entry is the fallback for unknown devices:

SENSORS_CONFIG = {
    0x38: {'driver': 'AHT10',  'title': 'aht10',  'name': 'rh_sortie',  'units': 'RH'},
    0x48: {'driver': 'TMP102', 'title': 'tmp102', 'name': 't_resistance', 'units': '°C'},
    'default': {'driver': 'Unknown', 'title': 'Unknown Sensor', 'name': 'unknow_sensor', 'units': ''},
}

Ready-made benches

Two configurations are provided:

• the default config.py — actuators driven in PWM (fan + heater), with the AHT10 humidity sensor, four TMP102 temperature probes and the EMC2101 controller;

• config_examples/config_pizero.py — actuators driven in all-or-nothing (DIGITAL) with a PT-100 probe, illustrating a very different bench.

To switch bench, copy the wanted file from config_examples/ over config.py.

Adding new hardware

Adding a component is just writing a small driver class and registering it; nothing else (transport, request handling, main.py) changes:

• a new sensor → a class in hardware/sensors.py registered in SENSOR_DRIVER_REGISTRY;

• a new actuator mode → a class in hardware/actuators.py registered in ACTUATOR_DRIVER_REGISTRY.

The driver chosen in config.py is then resolved from the matching registry at start-up.