Eiechip 9PCS/Lot Gas Detection Sensor Module MQ-2 MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-8 MQ-9 MQ-135 Sensor Module Gas Sensor Starter Kit

It is virtually impossible to know WHAT triggers a sensor because many of them are triggered by more than one chemical. There are similar gases that trigger many of the sensors. The sensors in the system are not calibrated, so they cannot be used to measure a specific gas' concentration. A sensor outputs an Analog value that reflects a correlation between its level and the level of gas it's designed to detect. But you can never be sure exactly which gas is triggering it. As for the analog output, it also appears to be nonlinear. Furthermore, there is a digital output pin that can be controlled (using a potentiometer) so that the digital output pin will be set high when a threshold An LED on the sensor board turns green when the digital pin on the board goes high. It is technically possible to use the sensors by just connecting power to them, and relying on a Green LED to inform you when the preset threshold is reached. It is also possible to trigger an alarm using the digital pin. You could hook an analog meter to the pin if you are interested in reading the Analog output, or you could connect the pin to a board like an Arduino or Raspberry Pi. A great deal of versatility is evident here. This type of device is not intended for use in monitoring hazardous environments, as these are designed for hobbyist use only. ** Update** A few sensors are hooked up in my house to monitor the indoor air quality. All sensors were run for 48 hours in order to ensure they were properly burned in. A number of substances were tested to determine the analog output from each sensor. Measurements of Min, Max, and Current are tracked. Following are a few samples that were used to test the response of each sensor. I soaked a paper towel with 91% isopropyl alcohol, lit the lighter with a butane grill spray, and filled a balloon with natural gas from the service port on our gas meter here are the results. As you waved the paper towel in front of each sensor for * 5 seconds, you noticed that every sensor reacted to the alcohol even those that are not specifically designed to respond to alcohol

It took about 30 minutes for the readings to return Then I went to try In order to release the Butane gas from the lighter, press the button for 2 seconds with the nozzel right up against the As before, EVERY sensor responded to the Butane. A further half hour later, we tried natural gas In addition, ALL of the sensors responded to the gas when I slightly opened the balloon end for one second just in front of each one. There is a pattern starting to emerge Taking any of the sensors into account, it is almost impossible to determine the gas detected, so I am now beginning to wonder whether they are even practical. There is no analog output for any of the sensors near zero, so you need to practice operating them in clear air and see what the "no detection" value is, and then use that value as a reference point. was unable to get any of the sensors to generate a higher analog output Perhaps the sensors outputs are scaled to use a lower voltage since I set my Arduino AREF to 5 volts and maybe the sensor outputs are set as well. The analog reference values of the sensors range from 400 to 200, with the MQ2 sensor starting at 200. There was a peak of *800 +- in all of the sensor's Analog outputs I think each sensor will be able to detect "nothing" for a maximum of 400 seconds before I figure it will detect.

Elias Kennedy

| Aug 25, 2020

The sensor units in this picture work, they are standard equipment. Getting them to stabilize and provide reliable readings is difficult - but well worth the wait The wait usually doesn't last more than 10 minutes. The two are being used to measure particulates in enclosures for 3D printing, and so far they have been very accurate. Each of these sensors operates at 5 volts and works Only challenge I had was that some of them had not yet been broken out (the frame PCB was still attached), so I had to break them off with a pair of pliers. Please do not use your hands, as they are.

Elizabeth Suarez

| Oct 01, 2020

This seems to work, but I am not sure how it works. It is not known what to do with the modules or how the raw sensors work on the internet at large, only about the sensors themselves.

I am giving them a 1 star review to get some support, but until I figure out how they work, they are sitting on my shelf.

Layla Cain

| Dec 31, 2020

The packets are neatly sealed to prevent static electricity. A blue Arduino soldermask identified this visitor as an Arduino official.

Bentley John

| May 04, 2021

Would you have ever thought one of these would be this expensive? And nine? Are you kidding me? I like this deal very much.

Phoenix Cooke

| Jan 02, 2021

There are a large number of gas sensors available for measuring different types of pollutants in the air. A similar microcontroller to Arduino can be easily connected with it, and it provides repeatable but uncalibrated.

Zachariah Martinez

| Mar 21, 2021

These sensors are excellent for use with Arduino. You can find lots of information about how to use the Arduino on the web. The seller also has a circuit diagram for the board where the sensors are.

Meghan Pineda

| May 21, 2021

The system seems to be working well.

Kora HOWELLS

| Sep 05, 2020