Compact air quality particulate sensor detects PM10, PM2.5 and PM1

“SN-GCJA5 features an innovative optical sensor assembly to provide reliable operation over a long lifetime while accurately detecting particles as small as 0.3µm,” according to Farnell, which is stocking the sensor. It has an “optimised air pathway structure that minimises dust accumulation making it possible to avoid tracking for electrical safety”.

Laser scattering allows it to provide a fast response (1s) to smoke, environmental dust, diesel exhaust and other nasties – including floating particles such as PM2.5, PM10 and PM1.

The unit is small – 37 x 37 x 12mm – and interfacing is through I²C or 3.3V UART – both are included. Level shifting is required to interface with 5V logic – the data sheet has simple circuits.

A fan is used inside to pulls in samples, although Panasonic claims high dust resistance and a long life, partly though auto-correction (right) which accounts for degradation of the photo diode and dirt on its surface.

An internal microcontroller runs an analysis algorithm and outputs across an indicatable range of 0 to 2,000μg/m³. It looks like max consistency error is 10% across 35 – 1,000μg/m³ – the data sheet seems a little unfinished on this point, and also still has ‘xxx’ for the I²C indicatable range.

Operation is over -10 to 60℃, <95%RH non-condensing.

Power requirements are 5V±10% at <100mA. Although response time is 1s, warm-up takes half a minute: 8s for initialisation (when it begins outputting readings) then 20s average processing time.

Farnell’s SN-GCJA5 product page is here and it has the data sheet here

Panasonic has a mini data sheet here

Panasonic also has a video – which is a bit thin and marketey, but does include an internal animation