Infinite L-com SRAQ-G012 User manual

CARBON MONOXIDE (CO) SENSOR MODULE
User Guide for SRAQ-G012
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M_L-com_SRAQ-G012_11/2022_R1.0
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Product Description
The SRAQ-G012 gas sensor module detects the presence and concentration of carbon monoxide gas. Integrated circuitry produces a voltage signal
corresponding to the gas concentration. Having high sensitivity to this dangerous odorless and colorless gas, the sensor module can detect carbon
dioxide concentrations ranging from 10 to 10,000 ppm. The SRAQ-G012 has both analog and level outputs with adjustable output sensitivity.
Features
 Features MQ7 sensing element
 Highly sensitive to carbon monoxide
 Analog and TTL level outputs
 4 pin male header
Applications
 Portable C02 detector
 Power generation
 Storage areas
 General indoor air quality monitoring
 Smart buildings and garages

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Technical Parameters
Electrical Diagram
 VCC is the 0  5 VDC power supply positive and negative; GND is the ground
 Aout is the analog output, Dout is the level output
 On the PCB, Indicator light on: Dout is low level. Indicator light off: Dout is high level
 The 1k resistor shown on the PCBA is the load resistance (RL), it can be changed by user. Due to the sensor itself the load resistance range
should be 100k  1M.
Mounting Diagram
Mount the PCBA to the enclosure with screws. Hole diameter 3mm, pitch distances as per the diagrams given below.
Working Voltage 5 VDC ± 0.2 V
Working Current <150 mA
Gas Detection Carbon monoxide
Detection Concentration 10  10000ppm (Carbon monoxide)
Preheating Time >30 mins
Response Time ≤1 sec
Recovery Time ≤30 sec
Output Mode
Aout (Analog signal) Vair~4.8V (non-linear)
Dout (Level signal) Low level: 0V; High level: 3.7V
Work environment
Temperature -10~50 °C
Humidity ＜95% RH

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Notes
1. Confirm the polarity and the voltage of the power supply before powering ON the sensor.
2. The analog output of this module is non-linear. When connect to microcontroller, it should be connected to ADC interface of the microcontroller.
3. The relationship between the resistance ratio and the concentration is a logarithmic relationship. For more info on typical sensitivity curve, check
MQ7 Probe on internet.
Typical Sensitivity Curve
Temperature: 20 °C
Humidity: 65%
Oxygen: 21%
RL = 20 kΩ
The ordinate is the resistance ratio of the sensor (Rs/Ro), and the abscissa is the gas concentration.
Rs: Resistance in various concentration value of gas
R0: Resistance in clear air
The calculation of the resistance ratio according to the output voltage is as follows:
The sensor is energized in relatively clean air for more than half an hour and after measure the output voltage value of Aout.
VCC is the power supply voltage, 5 VDC
RL is the load resistance
VRL = Aout = Vair value
When the sensor detects gas, the RS value can be calculated after measuring the value of Aout.
The VRL value at this time is the Aout value after gas is detected. It is different from the value of the above formula. The VCC value and the RL value
are the same as above.
The R0 and RS values are obtained, and the specific concentration value of the gas is converted by the RS / R0 value of the Sensitivity Characteristic
Curve.