wireless monitoring system of gas detector - Faculty of Electrical ...

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Figure 3.6: Gas Sensor Circuit Diagram [13]
The circuit diagram for both the sensor is the same as shown in Figure 3.6.There
are three output pins from this sensor which are reference voltage (VCC), ground pin
(GND) and the output voltage pin. RL shown in the Figure 3.5 is the adjustable
resistance. The connection between protection resistor in the sensor circuit and
adjustable resistor are in serial which form a load resistor (RL). The sensor‟s resistance
between Rs and RL form a voltage divider. Based on the chart provided in the MQ3 and
MQ6 data sheet, Rs in the clean air under given temperature and humidity constant.
Figure 3.6 also shows the sensor come out with 6pins. Pin H act as the coil of the gas
sensor. Meanwhile, pin A and B are connected in pairing and was connected as in the
circuit diagram above. The calculation for gas concentration is described in detailed in
section 3.3.1.
GAS SENSOR
1S
VCC
GND
A0
5V
GND
Figure 3.7: The Gas Sensor Connection to Arduino Pins.