sensord 0.1.4

This distribution package consists of two main components:

Sensord

The distribution package consists of two main components.

Sensor Service

• Executable: sensord
• Manages IoT devices and sensors using the Sensation library.
• Runs as a background process.
• Handles communication and data processing for connected sensors.
• Sends sensor data and events to external systems according to configured endpoints (MQTT, etc.)

Sensor Control CLI

• Executable: sensorctl
• Provides a command-line tool for controlling and interacting with the Sensor Service.
• Allows users to start, stop, configure, and monitor sensors through the command line.
• Offers a convenient way to manage the Sensor Service and connected devices.

Installation

The recommended way of installing this service is using pipx, since this is a Python application. See this manual about how to install pipx if it is not already on your system.

Installing for a given user

pipx install sensord

Installing system-wide

If your pipx is installed system-wide, you can also install this service globally.

sudo pipx --global install sensord

This makes sensord available for all users in the system, which can be convenient, for example, if you plan to run it as a systemd service by a dedicated user.

Sensord service

Execute by: sensord command or run as a systemd service

Never run more than one instance of the service at the same time. Especially, do not run simultaneously under a super user and a normal user.

Configuration Directory

All service configuration files must be placed in the sensord directory located in one of the configuration paths according to the XDG specification:

• For a given user: ~/.config/sensord or $XDG_CONFIG_HOME/sensord
• For all users: /etc/xdg/sensord or /etc/sensord

Sensors

Configuration

All sensors are configured in the configuration file sensors.toml which must be placed in the configuration directory. See the example configuration file.

SEN0395

Mandatory fields

• type: Specifies the type of the sensor. Must be set to "sen0395" for the SEN0395 sensor.
• name: A unique name for the sensor instance. Used for identification.
• port: The serial port to which the sensor is connected (e.g., "/dev/ttyAMA0", "/dev/ttyUSB0").

Optional fields

• enabled (default: true): If set to true, the service will start reading and processing sensor data (MQTT, presence logging, etc.).
• autostart (default: true): Specifies whether the sensor should automatically start scanning upon service startup.
• print_presence (default: true): Determines whether presence changes should be printed to stdout and logged.

Section [[sensor.mqtt]] (optional)

• broker: The name of the MQTT broker to which the sensor should publish presence data.
• topic: The MQTT topic under which the presence data should be published.

MQTT

Broker Configuration

Presence change events of a sensor can be sent as an MQTT message to an MQTT broker. For this, a broker must first be defined in the mqtt.toml configuration file. See the example configuration file.

Payload

The schema of the MQTT message payload is defined in the presence-mqtt-schema.json file.

Example

{
  "sensorId": "sen0395/desk",
  "event": "presence_change",
  "eventAt": "2024-05-30T06:25:13.929544+00:00",
  "eventData": {
    "presence": false
  }
}

Sensor Configuration

A sensor must explicitly define an MQTT broker for the notification to be sent. Multiple brokers can be defined to send notifications to different MQTT brokers:

[[sensor]]
# Sensor configuration is here
[[sensor.mqtt]]
broker = "local-rpi"  # Broker name defined as `broker.name` in the `mqtt.toml` file
topic = "living_room/desk/presence"  # Topic where the notification events are sent

[[sensor.mqtt]]
broker = "cloud-broker"  # Another broker name defined in the `mqtt.toml` file
topic = "sensors/living_room/desk/presence"  # Topic on the second broker

Systemd

To run this service as a systemd service, follow the steps below.

You can create a dedicated user for the service and add the user to the required groups (optional):

sudo useradd -r -s /usr/sbin/nologin sensord
sudo usermod -a -G dialout sensord

Note: dialout group is required for reading serial port on Raspberry Pi OS

Create the service file /etc/systemd/system/sensord.service:

[Unit]
Description=Sensor Daemon Service
After=network.target

[Service]
ExecStart=/usr/local/bin/sensord --log-file-level off
Restart=always
User=sensord
Group=sensord

[Install]
WantedBy=multi-user.target

Note: You can remove the --log-file-level off option if you want to log to /var/log/sensord. However, you need to set the corresponding permissions for the user.

Active and start the service:

sudo systemctl daemon-reload
sudo systemctl enable sensord.service
sudo systemctl start sensord.service

To manually debug, you can run the service as sensord user:

sudo -u sensord /usr/local/bin/sensord

To read the service logs in the journal:

 journalctl -u sensord

Sensor Control CLI

Execute sensorctl --help to see the available commands. This CLI utility communicates with the sensord service. The service must be running when a command is executed.

Note: If the service runs under a different user than the one executing sensorctl, then the current user must be added to the same group as the primary group of the service user. For example, if the service runs as the sensord user with the sensord group, then add the current user to the same group:

sudo usermod -a -G sensord $USER

After adding the user to the group, the user needs to log out and log back in for the group changes to take effect.

Subcommands

SEN0395

The sen0395 subcommand group provides commands for controlling the DFRobot mmWave presence sensor SEN0395. All subcommands accept the following option:

• --name NAME: The name of the specific sensor to execute the command on. If not provided, the command is executed for all registered sensors.

start
Start scanning with the SEN0395 sensor(s).

stop
Stop scanning with the SEN0395 sensor(s).

reset
Send a reset command to the SEN0395 sensor(s).

latency DETECTION_DELAY DISAPPEARANCE_DELAY
Configure the detection and disappearance latencies for the SEN0395 sensor(s).

detrange PARA_S PARA_E [PARB_S] [PARB_E] [PARC_S] [PARC_E] [PARD_S] [PARD_E]
Configure the detection range segments for the SEN0395 sensor(s).

status
Print the status of the SEN0395 sensor(s).

enable
Start reading and processing data from the SEN0395 sensor(s).

disable
Stop reading and processing data from the SEN0395 sensor(s).