jamesmoessis / dust_sensor

Arduino connected to a dust sensor which triggers output if adjustable dust level is exceeded.

dust_sensor

Arduino Mega connected to a dust sensor which triggers output if adjustable dust level is exceeded.

How it works

On a hardware level

• The dust sensor is power cycled at the start of the program. This is done via a PNP BJT (active low).
• A MOSFET (Active HIGH) is activated when averaged measurements exceed desired threshold level. This shorts an external input.
• A green and red LED are used to indicate threshold being exceeded (or not exceeded).
• The dust levels are communicated by the Honeywell HPMA115S0 via UART protocol.
• The Arduino Dust RX pin is pulled down toward ground via a 2k4 resistor. The TX is pulled up via a 2k4 resistor. This is to accomodate the difference in the communication voltage between the Arduino and the HPMA115S0. Arduino communicates via 5V and the HPMA via 3.3V.
• This is indicated via the schematic DESIGN_SCHEMATIC.pdf.

On a software level

• The third party hpma115S0.h Arduino library is used to communicate with the sensor. https://github.com/felixgalindo/HPMA115S0
• The main code is in the Arduino sketch dust_sensor.ino
• The measurements are taken in bursts, separated by one minute break. The sensor is powered off in between bursts to preserve its lifetime.

Monitoring

todo

Remote Control

todo

Web User Interface

• frontend/ contains a basic react application created with npx create-react-app.
• The repository does not contain the module files to run the react app. Run the command npm install while in the directory to install necessary dependencies which are listed in package.json.
• Once it's installed, running npm start in the command line will start the application and open it in a localhost browser window.
• More information on scripts is provided in the README file provided by react in frontend/