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Published in: Meshlium, News, Plug & Sense!, Smart Cities, Waspmote

New Calibrated Air Quality Sensors for Smart Cities

New Calibrated Air Quality Sensors for Smart Cities

May 5th, 2015 - Libelium

Libelium released a new Gases PRO Sensor Board in May 2015. This platform features precision sensors to enable the implementation of urban monitoring, air quality, industrial, environmental or farming projects with high requirements in terms of accuracy, reliability, and measurement range. The new gas sensors line is available for both Waspmote OEM and Plug & Sense!.

Two different Sensor Boards are available to monitor and measure gas levels: Gases Sensor Board (Gases) and Gases PRO Sensor Board (Gases PRO).

New Gases PRO Sensor Board for Waspmote OEM

New Gases PRO Sensor Board for Waspmote OEM

Comparative Gases and Gases PRO Sensor Boards:

  • Number of sensors: Gases PRO integrates 16 different gas sensors. The original Gases board integrates 12. See the complete list of parameters in the tables below.
  • Increased accuracy: Gases PRO measures exact values of gas concentration in ppms. The Gases board shows a range of concentration low / medium / high. Details of the accuracy ranges figure in the tables below.
  • Precision sensors: A sensitive new particulate matter sensor—commonly known as dust sensor—is included in the Gases PRO board. This sensor allows the measurement of PM1, PM2.5, and PM10 particles and comes calibrated from the factory.

Should I choose Gases or Gases PRO?

Libelium has created different systems in terms of accuracy and pricing. The customer should consider Gases PRO if she needs maximum performance sensors for metering that require accurate ppm or percentage. If the project just needs to detect gas presence or gas levels, the standard Gases Sensor Board is sufficient.

The new Gases PRO Sensor Board can read up to 16 gas sensors; it also has a high-end sensor for three parameters: temperature, humidity and pressure.

Gases PRO [New Version]
Parameter Range Accuracy *
Temperature -40 to +85 ºC Calibrated
±1 ºC
(±0.5 ºC at 25 ºC)
Humidity 0 to 100% HR Calibrated
±3% RH (at 25 ºC, range 20 ~ 80% RH)
Pressure 30 to 110 kPa Calibrated
±0.1 kPa (range 0 ~ 65 ºC)
Carbon Monoxide
CO
0 to 1000 ppm Calibrated
±2 ppm
Carbon Dioxide
CO2
0 to 5000 ppm Calibrated
±50 ppm (range 0~2500 ppm)
±200 ppm (range 2500~5000 ppm)
Molecular Oxygen
O2
0 to 30% Calibrated
±25 ppm
Ozone
O3
0 to 5 ppm Calibrated
±0.005 ppm
Nitric Oxide
NO
0 to 250 ppm Calibrated
±0.5 ppm
Nitric Dioxide
NO2
0 to 20 ppm Calibrated
±0.1 ppm
Sulfur Dioxide
SO2
0 to 20 ppm Calibrated
±0.1 ppm
Ammonia
NH3
0 to 100 ppm Calibrated
±0.5 ppm
Methane and other combustible gases
CH4
0 to 100 % / LEL Calibrated
±0.15 % LEL
Molecular Hydrogen
H2
0 to 20000 Calibrated
±1 ppm
Hydrogen Sulfide
H2S
0 to 200 ppm Calibrated
±10 ppm
Hydrogen Chloride
HCl
0 to 50 ppm Calibrated
±1 ppm
Hydrogen Cyanide
HCN
0 to 50 ppm Calibrated
±0.2 ppm
Phosphine
PH3
0 to 20 ppm Calibrated
±0.1 ppm
Ethylene Oxide
ETO
0 to 100 ppm Calibrated
±1 ppm
Chlorine
Cl2
0 to 50 ppm Calibrated
±0.1 ppm
Particle Matter – Dust 0.5 to 16 μm
(16 steps) (includes PM1, PM2.5 and PM10)
Calibrated

* Accuracy values have been calculated at average conditions: 20ºC / 101300 Pa. Accuracy levels may differ with different temperature and pressure levels, aging and in presence of third type of gases which cause cross sensitivity. See each Gas Sensor documentation for more information.

Gases v2.0 [Old Version]
Parameter Range Accuracy *
Temperature 40 to +125 ºC Not calibrated
±2 ºC (range 0 ~ 70 ºC), ±4 ºC (range -40 ~ 125 ºC)
Humidity 0 to 100% HR Not calibrated
<±4% RH (at 25 ºC, range 30 ~ 80% RH),
<±6% RH (range 0 ~ 100% RH)
Pressure 15 to 115 kPa Not calibrated
<±1.5% V (range 0 ~ 85 ºC)
Carbon Monoxide
CO
30 to 1000 ppm Not calibrated
Carbon Dioxide
CO2
350 to 10000 ppm Not calibrated
Molecular Oxygen
O2
0 to 30% Not calibrated
Ozone
O3
0.010 to 1 ppm Not calibrated
Nitric Dioxide
NO2
0.05 to 5 ppm Not calibrated
Ammonia
NH3
10 to 100 ppm Not calibrated
Methane and other combustible gases
CH4
500 to 10000 ppm Not calibrated
Molecular Hydrogen
H2
500 to 10000 ppm Not calibrated
Hydrogen Sulfide
H2S
0.1 to 3 ppm Not calibrated
Isobutane
C4H10
50 to 5000 ppm Not calibrated
Ethanol
CH3CH2OH
1 to 30 ppm
50 to 5000 ppm
Not calibrated
Toluene
C6H5CH3
1 to 30 ppm Not calibrated
Volatile Organic Compounds 30 to 400 ppm Not calibrated
Hydrocarbons - Not calibrated

How are the Gases PRO sensors calibrated?

All the Gases PRO sensors are linear, so they behave according to a simple line like y = f(x) = m·x + c. On the other hand, the Gases Sensor Board sensors show a logarithmic response, which is harder to handle.

All the gas sensors for Gases PRO are calibrated by the sensor manufacturers, in laboratories. To obtain maximum accuracy, a two-point calibration process is performed on controlled concentrations of gas in vacuum chambers. Due to the linear nature of the sensors, these two points are enough to correct the two possible drifts in m (slope) and c (constant offset). Our sensor manufacturers provide a calibration certificate for each individual sensor, with two calibration parameters. Libelium stores these parameters in an EEPROM, a non-volatile memory chip inside each gas sensor. When the user performs a sensor reading, the software system designed by Libelium reads the sensor signal and the two parameters. These three values are processed by the system, and a temperature compensation calculation is applied. From this data we obtain the concentration value in ppms – the value we want to measure.

The new Temperature, Humidity and Pressure sensor for Gases PRO is calibrated in the factory. It comes with three calibration points for temperature, six points for humidity and nine points for pressure. These three parameters are automatically inter-compensated to obtain extreme accuracy.

Plug & Sense! Smart Environment PRO including new Gases PRO Sensor Board

Plug & Sense! Smart Environment PRO including new Gases PRO Sensor Board

Gases PRO Sensor Board is included in Libelium's new Smart Cities sensing solution, Plug & Sense! Smart Environment PRO. This board also allows to obtain information about particle size and density ranging from 1um to 10um (PM1 / PM2.5 / PM10) in its surroundings, using the new particulate matter sensor—commonly known as dust sensor.

For more Technical information go to Waspmote and Plug & Sense! website, and to the Gases PRO Technical Guide .

If you are interested in purchase information please contact the Libelium Commercial Department.

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