Raspberry Pi pHAT detects indoor pollution, and optionally, outdoors too

Pimoroni’s $57 “Enviro+” pHAT for the Raspberry Pi can detect indoor air quality, temperature, pressure, humidity, light, and noise. You can hook up an optional “PMS5003 Particulate Matter Sensor” for detecting outdoor pollution.

In 2016, Pimoroni launched a $20 Enviro pHAT board for the Raspberry Pi. The name was a bit misleading, however, since its environmental sensors were limited to a temperature/pressure sensor, light sensor, and whatever you could hook up via the 4-channel analog to digital converter (ADC). Now, the UK-based company has returned with a 45-Pound ($57) Enviro+ pHAT that loses the accelerometer/magnetometer, but adds humidity and analog gas sensors, a MEMS microphone for detecting noise levels, and a 1-inch color LCD screen.

Enviro+, front and back
(click images to enlarge)

The fully-assembled pHAT (partial HAT) form-factor board is ideally suited for a pairing with the similarly sized Raspberry Pi Zero or Zero W. However, it’s compatible with all 40-pin RPi boards. The Enviro+, which we read about in Fossbytes, also has a connector for hooking up Plantower’s 25-Pound ($32) PMS5003 Particulate Matter Sensor. The PMS5003 is designed for checking outdoor pollution (see farther below).

Enviro+ (left) and original Enviro pHAT
(click images to enlarge)

Specification listed for the Enviro+ include:

  • BME280 temperature, pressure, humidity sensor
  • LTR-559 light and proximity sensor
  • MICS6814 analog gas sensor
  • ADS1015 ADC with spare channel for adding another analog sensor
  • MEMS microphone
  • 0.96-inch, 160 x 80 color LCD
  • I2C pins for attaching Pimoroni I2C breakouts
  • Connector for PMS5003 Particulate Matter Sensor
  • Python libraries, examples, and tutorial on GitHub with IFTTT and Alexa support

Even if you don’t live in an area with extensive outdoor air pollution, you’re probably breathing in more indoor pollutants than are good for you. Of course, that depends on your home’s ventilation system and potential pollution sources. Indoor pollutants include everything from smoke and carbon monoxide to fumes from carpets, industrial cleaners, and non-stick cooking pans. Their effects can range from headaches and irritations to long-term respiratory problems and cancer.

The Enviro+ may not be able to detect all of these pollutants to the level of a professional detection system costing thousands of dollars, but the new MiCS-6814 (PDF) sensor from SGX Sensortech can cover the non-particulate basics. It detects carbon monoxide, nitrogen dioxide, Ethanol, hydrogen, ammonia, methane, propane, and iso-butane.

The gas sensor provides qualitative measurements of changes in gas concentrations, “so you can tell broadly if the three groups of gases are increasing or decreasing in abundance,” says Pimoroni. The temperature, air pressure, and humidity sensors can not only be used to monitor general indoor conditions, but their readings “can all affect particulate levels,” giving you a more complete picture of air quality, says the company.

PMS5003 Particulate Matter Sensor

Developed in collaboration with the University of Sheffield, the Enviro+ is primarily designed to control Plantower’s new PMS5003 Particulate Matter Sensor to check real-time external air quality. The combined platform can be used to contribute to open data citizen science projects like Luftdaten, says Pimoroni.

PMS5003 Particulate Matter Sensor
(click images to enlarge)

The PMS5003 sensor senses and discriminates between PM1, PM2.5, and PM10 particulates in various sizes. It can detect pollutants from sources like smoke, dust, pollen, metal, and organic particles.

A small fan sucks air through the sensor and past a laser that can detect both the concentration and size of particles. A serial port and cable are also included.

Although Pimoroni suggests the 50 x 38 x 21mm PMS5003 device is designed for outdoor use near your home, Plantower does not appear to mention this restriction. Still, in typical residential scenarios, particulate pollution detected inside would usually come from the outside.

Further information

The Enviro+ is available for 45 UK Pounds ($57), and the PMS5003 Particulate Matter Sensor sells for 25 Pounds ($32). Add 13 Pounds ($16.40) for a pre-soldered Raspberry Pi Zero WH. More information may be found at Pimoroni’s Enviro+ and PMS5003 shopping pages, and Plantower’s PMS5003 product page.


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