Simply power the module with 5V and you should notice the power LED on the module to glow and when no gas it detected the output LED will remain turned off meaning the digital output pin will be 0V. You can either use the digital pin or the analog pin to do this.
#Fritzing alternative how to#
How to use MQ-135 Sensors to detect gases If you are looking for a sensor to detect or measure common air quality gases such as CO2, Smoke, NH3, NOx, Alcohol, Benzene then this sensor might be the right choice for you. The analog pin is TTL driven and works on 5V and so can be used with most common microcontrollers. If you need to measure the gases in PPM, the analog pin need to be used. The MQ-135 sensor module comes with a Digital Pin which makes this sensor to operate even without a microcontroller and that comes in handy when you are only trying to detect one particular gas. The MQ-135 Gas sensors are used in air quality control equipments and are suitable for detecting or measuring of NH3, NOx, Alcohol, Benzene, Smoke, CO2. But if you planning to measure the PPM of a gas it is recommend buying the sensor alone without module.
If you are trying to only detect (not measuring PPM) the presence of a gas, then you can buy it as a module since it comes with an op-amp comparator and a digital output pin. MQ135 is available as a module or as just the sensor alone.
#Fritzing alternative series#
When it comes to measuring or detecting a particular Gas, the MQ series Gas sensors are the most inexpensive and commonly used ones. Note: Complete technical information can be found in the MQ-135 Datasheet linked a the bottom of this page.īenzene, Toluene, Alcohol, Propane, Formaldehyde gas, Hydrogen The Sensitivity of Digital pin can be varied using the potentiometer.Can be used as a Digital or analog sensor.Digital output voltage: 0V or 5V (TTL Logic).Detect/Measure NH3, NOx, alcohol, Benzene, smoke, CO2, etc.
One pin will act as output while the other will be pulled to ground.