User Guide for Environmental (VOC) sensor

This guide will only cover the VOC sensor.

The Environmental sensor is designed for indoor use with capable of sensing volatile organic compounds (VOC). Common examples are cleaning fluids, cleaning solvents, paint thinners and gasoline vapors. In addition to sensing of VOC, the sensor is capable of sensing temperature, humidity, pressure, ambient light intensity and local acoustic pressure.

Technical documentation can be found here.

Installation

Click here to read more on how to install batteries and how to mount the device to the wall. The device can be hung on a wall or a cabinets, etc. using its magnetic backing or with the wall bracket. Avoid areas with lot of dust, vibration or sprayed water. Note that the unit is not designed for outdoor use.

Calibration

The VOC sensor will automatically calibrate itself based on its background history so that typically good air are represented by values of ~25 IAQ and typically bad air by values of ~250 IAQ. Values above or below these marks would be expected if the air quality observed by the sensor is significantly outside of sensor's current calibration bounds and while sensor is re-calibrating.

In Use

Default sample rate for the Environmental device is 60 minutes, this sample rate can be changed by pushing out a downlink message to the device. This user guide will not cover how to send downlink message to LoRa or NarrowBand devices, click here to find more guides.

Due to internal calibration process of the VOC is 5 minutes, the minimum sample rate you can set for the sensor is 5 minutes. Setting the sample rate less than 5 minutes does not provide better measurement resolution and the sensor consumes more battery.

The VOC sensor measuring Indoor Air Quality (IAQ) index between 0 to 250. Following table presents air quality versus IAQ index.

IAQ Index Air Quality
0-50 Excellent
51-100 Good
101-150 Fair
151-200 Poor
201-300 Bad
301-500 Inadequate

In addition to IAQ, the sensor also returns IAQ state which defines current state of the Air Quality sensor, this parameter can be used to assess the reliability of the IAQ index currently being delivered.

IAQ State Description
0 Air Quality sensor needs to stabilize to its new environment.
1 Air Quality sensor's history is uncertain, new calibration is needed.
2 A new extremum in air quality has been detected, sensor is now being calibrated.
3 Calibration is done, sensor is running with optimal performance.

Initially, IAQ index will remain fixed at 25 and state at 0 for at least 20 minutes, after which it will automatically switch to 1. 

Service and Maintenance

The batteries are the only user serviceable parts of the device. Depends on sample rate, temperature and signal strength such as range to the LoRaWAN gateway or NarrowBand base stations, the batteries should last 5 to 7 years for LoRA and 3 to 5 for Narrowband. Note: battery self-discharge is typical 1-2% per year.

Click here to read more about replacing of the batteries.

Precautions

  • Read all instructions in this manual.
  • Keep instrument dry.
  • Never let water or other liquids into the sensor.
  • Do not drop the device or subject it to continuous vibration.
  • Do not store in high levels of dust.
  • Do not clean the instrument with cleaning chemicals or solvents. Clean it with a damp cloth.
  • Do not operate near heavy aerosols (spray) usage or where oxygen Is being administered.