Room Condition Monitor (rcm)

A pet project for room temperature, pressure and humidity monitoring and reporting.

The project consists of device, back-end and planned front-end parts.

Please note that this is an effort with limited resources focusing on exploring technologies. Some parts may unfortunately not be cross-platform or may be somewhat more complex than necessary.

Device

The device part focuses on collecting data locally and optionally uploading them to remote storage of back end.

The collected data are also available over a locally served ASP.NET Core Razor Pages web UI.

The implementation currently supports Linux with BME280 sensor connected over I2C.

Prerequisities

• .NET 8 SDK
• Node.js and npm (npm is auto-included in Node.js)

Configuration

The application is configured according to ASP.NET Core configuration.

The following additional properties are supported:

Property	Possible values	Required	Description
Measurements:Access:Mode	STUB, I2C	Required	Defines the data access mode for periodic condition measurements. In STUB mode, measurements are generated randomly within sensible ranges. In I2C mode, measurements are read from I2C bus.
DataStorage:Path	path string	Required	Specifies a directory used to store measurements and backend connection parameters. If a relative path is supplied, it is evaluated based on the working directory of the executing binary.

I2C

When configured with Measurement:Access:Mode = I2C, the following options are also applied:

Property	Possible values	Required	Description
Measurements:Access:BusAddress	string	Required	I2C bus address, e.g. /dev/i2c-1 from ls /dev/*i2c*
Measurements:Access:DeviceAddress	byte	Required	I2C device address, e.g. 0x76 from i2cdetect -y 1

Note that the above requires I2C interface to be enabled on the device through raspi-config to detect I2C device and i2c-tools to be installed (sudo apt-get install i2c-tools) to run i2cdetect.

Running

Development

Executing dotnet run --project src/Device/Rcm.Device.Web --measurements:access:mode=STUB --dataStorage:path=../../../data --console will run the data collection and web UI service with basic development configuration.

The --console switch causes the application to run in console. If the switch is omitted, the application will asume it is running as a Linux systemd service.

Note that the --console switch is required to come last in order to avoid misinterpretation by ASP.NET Core configuration.

Except --console, the parameters may also be specified in appsettings.json files or environment variables. See configuration section for more details.

Device

For actual device deployment, it is suggested to publish the application binary and run it as a systemd service on the target system.

For a self-contained release publish, run dotnet publish src/Device/Rcm.Device.Web/Rcm.Device.Web.csproj --runtime linux-arm --configuration Release --self-contained

The following unit definition can be used as a baseline, it assumes the application was deployed to /home/pi/apps/rcm/bin and binds to port 80 (HTTP).

[Unit]
Description=Room Condition Monitor

[Service]
Type=notify

# Configure data storage location and I2C bus
Environment=DATASTORAGE__PATH=/home/pi/apps/rcm/data MEASUREMENTS__ACCESS__MODE=I2C MEASUREMENTS__ACCESS__BUSADDRESS=/dev/i2c-1 MEASUREMENTS__ACCESS__DEVICEADDRESS=0x76

# Start the self-contained application with binding on port 80
ExecStart=/home/pi/apps/rcm/bin/Rcm.Device.Web --urls="http://0.0.0.0:80"

# Restart on error after 60s timeout
Restart=on-failure
RestartSec=60

[Install]
# Start before non-GUI shells
WantedBy=multi-user.target

Back end

TODO

Front end

This component is not implemented yet.