MQ303A Alcohol Sensor Module

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MQ303A alcohol gas sensor belongs to the MQ gas sensor family. MQ303A is a Metal Oxide Semiconductor (MOS) type of sensor, originally belonging to the class of chemresistors; a class of resistance-based sensors in which the sensing is based on the change of resistance of the sensing material when exposed to alcohol. MQ303A is a heater-driven sensor. That’s why it is enclosed in two layers of fine stainless steel mesh called an Anti-explosion network. This ensures that the heater element inside the sensor will not cause an explosion, as we are sensing flammable gas (alcohol).

MQ303A gas sensor has a high sensitivity to Alcoholic gases and possesses a fast trigger response time. The sensor’s output is analog resistance corresponding to the concentration of Alcohol gas in the vicinity. The drive circuit is very simple; all that is required to do is to power up the heater coil with 5V, add a load resistance, and connect the output to an ADC.

MQ303A Alcohol Sensor

MQ303A Gas Sensor Key Features

  • High sensitivity to Alcoholic Gases and fumes
  • Stable and Long Life
  • Detection Range: 10 – 300 ppm, NH3(Ammonia gas), 10 – 1000 ppm, Benzene, 10 – 300 Alcohol
  • Heater Voltage: 5.0V
  • Standard Encapsulation: Bakelite
  • Fast response characteristics
  • With mounting holes for easy permanent installation
  • Main chip: LM393 Voltage comparator
  • Dimensions: 18mm Diameter, 17mm High excluding pins, Pins – 6mm High
  • Long life and low cost

MQ303A Gas Sensor Pinout

MQ303A Alcohol Sensor Pinout
Pin NamePin No.Description
VCC1This pin powers the module, typically the operating voltage is +5V
GND2Used to connect the module to the system ground
DO3You can also use this sensor to get digital output from this pin, by setting a threshold value using the potentiometer
AO4This pin outputs 0-5V analog voltage based on the intensity of the gas.

Specifications

  • Heater voltage: 0.9V ± 0.10V
  • Circuit voltage: Less than 6 V
  • Load resistance: Variable
  • Heater resistance: 4.5 Ω ± 0.5 Ω
  • Heater current: Less than 130 mA
  • Heater power consumption: Less than 130 mW
  • Power dissipation of sensing element: Less than 10 mW
  • Operating temperature: -10 C to 50 C
  • Storage temperature: -20 C to 70 C
  • Relative humidity: Less than 70% RH
  • Oxygen concentration: 21%±1%(Standard condition)
  • Sensor resistance: (20kΩ to 200 kΩ)
  • Sensitivity: (0.50 ± 0.15)
  • Frequency: 100 cpm
  • Vertical amplitude: 4 mm

Applications

  • Breathalyzer for alcohol blood level estimation.

Datasheet

You can download the datasheet for MQ303A Alcohol Sensor Module by clicking the link given below:

See Also: CD4059 Program Divide-by-N Counter | DS3231 Precision I2C Real-Time Clock Module | MT8870D Integrated ISO2-CMOS DTMF Receiver Module