FW Sense Hat

Simple Python module that read data from Sense Hat and share them on the local DBus.
This repository is part of the Smart Van Project.

FW Name: FW Sense Hat
FW Group: com.robypomper.smartvan.fw.sensehat
FW Version: 1.0.0

README | CHANGELOG | TODOs | LICENCE

Once ran, this script reads data from the Sense Hat board via I2C then notify the DBus with updated values. The Sense Hat is a crucial component equipped with a variety of sensors and accessible ICs through the I2C protocol. Each of these components has its dedicated Python file (located in the fw_sensehat/sense/chip folder). These files facilitate the reading and processing of raw data collected by the sensors. More info on Supported devices and value mapping.

Run

This is a Python script, so python is required to run it.

$ python --version
# if not installed, then run
$ sudo apt-get install python3 python3-pip

In addition, some other package must be installed in order to configure python's dependencies like PyGObject or pydbus. If you are using a debian/ubuntu based distribution, then you can run:

$ sudo apt-get install libcairo2-dev libgirepository1.0-dev dbus-x11

Once Python was installed on your machine, you can install the script's requirements globally or create a dedicated venv.

# Init venv (Optional)
$ python -m venv venev
$ source venv/bin/activate

# Install script's requirements
$ pip install -r requirements.txt

Now, you are ready to run the script with the command:

$ python run.py

or alternative options
$ python run.py --quiet
$ python run.py --debug --simulate
$ python run.py  --dbus-name com.custom.bus --dbus-obj-path /custom/path --dbus-iface com.custom.IFace

For script's remote usage please see the dedicated page.

Defaults DBus params are:

• DBus Name: com.waveshare.sensehat
• DBus Obj Path: DEV_TYPE_* as device code (eg: Sense Hat c become /sense_hat_c, see Supported devices for the full list of DEV_TYPE_* values)
• DBus Interface: DEV_IFACE_* (eg: com.waveshare.sensehat_c, see Supported devices for the full list of DEV_IFACE_* values)

Script's arguments

The run.py script accept following arguments:

• -h, --help: show this help message and exit
• -v, --version: show version and exit
• --simulate: Simulate a Sense Hat (C) Device (default: False)
• --dbus-name DBUS_NAME: DBus name to connect to (Default: com.waveshare.sense)
• --dbus-obj-path DBUS_OBJ_PATH: DBus object path to use for object publication (Default: the device_type_code string)
• --dbus-iface DBUS_IFACE: DBus object's interface (Default: current device's dbus_iface)
• --dev: enable development mode, increase log messages
• --debug: Set log level to debug
• --quiet: Set log level to error and

Develop

The main goal for this script is to link the Device's protocol to the DBus. So, in addition to the main script, all other files are related to the Device or to the DBus protocols.

Module's files can be grouped in 2 categories:

Definitions:

• ups/mappings.py: definition of PID, PROPS_CODES and CALC_PROPS_CODES tables
• ups/_definitions.py: definitions of supported devices, DUbus ifaces and custom properties types
• ups/_parsers.py: custom properties parsers
• ups/_calculated.py: custom properties calculators and data generator methods for simulator
• ups/_dbus_descs.py: definition of DBus iface's descriptors

Operations:

• run.py: main firmware script
• ups/device.py: class that represent the device
• ups/simulator.py: class that represent the simulated device
• dbus/obj.py: class that represent aDBus object to publish
• dbus/daemon.py: methods to handle the DBus daemon
• commons.py: commons properties parsers and simulator methods
• device.py: base class for devices
• device_serial.py: base implementation for serial devices

References

• Sense Hat (C) Wiki
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