Air Quality Monitor

The Weatherduino - Air Quality Monitor its a very simple to build device, suited to measure PM2.5 and PM10 air dust particles.
Based on the PM2.5 readings, and in accordance with EPA standards the Air Quality Index is computed by using Nowcast functions implemented on the software.
Currently, two models of dust particles sensors are supported:

• PMS7003, from the well reputed brand Plantower.¹⁾
• Nova SDS011 made by Inovafitness.

Through the use of an optional MH-Z19 sensor, the Air Quality Monitor can also be used to monitor CO2 levels in a room, greenhouse or outside.³⁾
The AQM (Air Quality Monitor) device can work in two different modes. Both modes can work simultaneously.

• Work like a transmitter unit, providing WeatherDuino weather stations²⁾ with Air Quality data, which by turn can be uploaded to WU, ThingSpeak or even to your own server for SQL storage.
• Work as an independent device, that could be used by anyone, no matter have or not an WeatherDuino weather station.

Bellow, in the General Assembling Guide / Hints section, we will explain how to build the AQM for each mode of use.

Microcontroller: Arduino Nano
RF Frequency: 433Mhz or 315Mhz ⁴⁾
Dust Sensor: PMS7003 or Nova SDS011
CO2 Sensor: MH-Z19 (optional)
Power Requirements: 9VDC 1A power supply

• Get the Part List from here: WeatherDuino Pro2 & Pro2 PLUS - PCB and Parts lists
  
• Always buy the PMS7003 sensor with the adapter cable included.
• There are two versions of the MH-Z19 sensor, preferably choose the MH-Z19B version.

The Air Quality Monitor should be installed in a well ventilated area outside the house, which not means it needs to be exposed directly to elements such as rain, or direct sunlight.
A porch or a balcony may be a good place for installing it.
Choose a enclosure suitable for the environmental conditions of the place where the AQM will be installed. If exposed to rain, enclosure should be waterproof, but able to allow circulation of outside air.

¹⁾ - The very expensive PurpleAir Air Quality Monitor, uses an Plantower sensor (the PMS5003, older than PMS7003).
²⁾ - See systems compatibility here.
³⁾ - Precision measure of CO2 concentration in open air, is a very complicated task no achievable with simple equipment. According to specifications the error margin of an MH-Z19 sensor is +- 50ppm for indoor use, maybe more in outdoor use.
⁴⁾ - Must match the frequency used by other Transmitter units.