air quality

D9 Air Quality Detector

This time OCRKJ D9-H. Which also can be found in some shops as unbranded LCD Digital Air Quality Monitor (AKA monllac, AgoHike, Robincure). Similar to OCRKJ K6-D from the previous review. It was bought for about 100$. Yet another portable device with 10 hours battery life and correct CO2 measurements.

D9 Air Quality detector


  • 3000 mAh battery ( 10 hours of battery life)
  • additional sensors (HCHO, VOC and PM2.5)
  • 16 different screens including trends
  • Active airflow with the relatively quiet fan
  • quality design and schematic inside (no glues, connectors, replaceable sensors)
  • good CO2 sensor inside – SenseAir S8 LP


  • slow charging – 8 hours (in operation mode)
  • no connectivity (Bluetooth, wi-fi, USB mass storage)
  • no ambient light sensor
  • unconfigurable high CO2 limits (GOOD is up to 1000 ppm)
  • wrong temperature and RH measurements (+3C, -10%RH)

It looks like relatively cheap SHT20 temperature and humidity sensor inside make it sort of a lottery if you will get correct measurements or not.

See device insides:

SALE Price was: 102$

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