Datenblatt für MIKROE-2516 von MikroElektronika

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Pollution click
PID: MIKROE-2516
Weight: 23 g
Pollution click has high sensitivity to organic gases such as methanal (also known as
formaldehyde), benzene, alcohol, toluene, etc. The click carries the WSP2110 VOC gas sensor
with the detection range of 1～50ppm (parts per million).
Pollution click is designed to run on a 5V power supply. It communicates with the target MCU
over AN and RST pin on the mikroBUS™ line.
WSP2110VOCgassensor
WSP2110 VOC gas sensor is a MOS type (metal oxide semiconductor) sensor that detects
volatile organic compounds such as methanal, benzene, alcohol and other types of gases that can
be harmful to one’s health in high concentrations.
The concentration of the target gas affects the conductivity of the sensor. Higher concentration of
the gas means the conductivity of the sensor gets higher as well.
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For precise calibration, the sensor needs to preheat (once powered up, it takes 120h to reach the
right temperature).
Sensor’ssensitivity
P1 potentiometer onboard is used for trimming the sensor’s sensitivity. Enable the pin drive gate
of heaters MOSFET switch to reduce power consumption when the click is not in use.
Detectionrange
The detection range of the sensor is 1～50ppm (part per million). Parts per million is the
numbers of parts of a component in 1 million parts of the gas mixture, it's the ratio of one gas to
another.
Volatileorganiccompounds
Volatile organic compounds or VOCs are organic chemicals. They have very high vapor pressure
at room temperature, and some of them can be harmful to human health. As most people spend a
lot of time indoors it’s important to know if the quality of the air is good. With Pollution click
you could always know if your indoor environment is healthy enough.
Keyfeatures
WSP2110VOCgassensor
o Detectionrange1～50ppm(partspermilion)
o Sensitivity:Rs(inair)/Rs(in10ppmtoluene)≥3
Interface:ANandRSTpin
5Vpowersupply
SPECIFICATION
Product Type Gas
Applications Automatic exhaust devices, air cleaners, harmful gas detection devices, etc.
On-board modules WSP2110 VOC gas sensor
Key Features Detection range 1～50ppm, Sensitivity S Rs(in air)/Rs(in 10ppm toluene)≥3
Key Benefits High sensitivity to organic gases
Interface AN, RST
Power Supply 5V
Compatibility mikroBUS
Click board size M (42.9 x 25.4 mm)
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Pinoutdiagram
This table shows how the pinout on Pollution click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
NotesPin
mikroBUStm
Pin Notes
AnalogoutpinAN1ANPWM16 NC Notconnected
EnablesensorRST2RSTINT15 NC Notconnected
NotconnectedNC3CSRX14 NC Notconnected
NotconnectedNC4SCKTX13 NC Notconnected
NotconnectedNC5MISOSCL12 NC Notconnected
NotconnectedNC6MOSISDA11 NC Notconnected
NotconnectedNC73.3V5V10 +5V Powersupply
GroundGND8GNDGND9GND Ground
Programming
The demo first enters in calibration procedure, before measuring pollution. In order to show
accurate results, calibration must be done in clean air. Because the sensor has slow response
time, it needs time to stabilize and to achieve working temperature. It also measures load
resistance, and shows value on the display so the user can set the desired sensitivity. After the
calibration is done, the demo enters in the measuring procedure.
Calibration procedure:
1)Putthesensorincleanairandadjusttheclickboardpotentiometertomaxvalue.
2)Waitforthemeasuredvalueontheloadresistortostabilize.
3)Pressthecontinuebutton.
4)Adjustthepotentiometertodefinethesensitivity.
5)Pressthecontinuebutton.
Detection range: 1ppm ~ 50ppm (parts per million).
Codesnippet
The function calculates the ppm value from the RS/R0 ratio. Where R0 is resistance in clean air,
and RS is resistance in target gas, with different concentration. The constants are extracted from
the sensitivity curve, for the sensitivity curve of alcohol given in the sensor datasheet.
01: float ratio_to_ppm(float ratio)
02: {
03: if (0.84 > ratio && ratio >= 0.53) // I segment
04: return pow((ratio/C1), (1/M1));
05:
06: else if (0.53 > ratio && ratio >= 0.39) // II segment
07: return pow((ratio/C2), (1/M2));
08:
09: else if (0.39 > ratio && ratio >= 0.1) // III segment
10: return pow((ratio/C3), (1/M3));
11:
12: else if (ratio < 0.148)
13: return 50.0;
14:
15: return 1.0;
16: }
https://shop.mikroe.com/click/sensors/pollution 2/24/2017