mq131

I have a this mq131 sensor do i use the mq131 library but in the library there were note that do not connect the mq131 to arduino pins but i have the sensor module not the sensor so that I use the code

Post a link to the schematics of that module or attach it to the post! If you don’t have one yet, ask your vendor for one.

This is the sensor module, one of several out there. Here is what they say:

with the signal light indicates the output;
the dual signal output (analog output, and TTL-level output);
TTL output valid signal is low; (low output signal light, can be accessed by the microcontroller IO port)
the analog output increases with the concentration, the higher the voltage the higher the concentration;
the ozone gas with high sensitivity (detection concentration range 10PPB-2PPM Ozone)
with a long life and reliable stability;
Fast response characteristics;
with mounting holes to facilitate fixed installation;
the probe can plug design for easy testing.

This is an example of the actual sensor . Most of this stuff does not exactly come with an accurate data sheet. My best guess on your module is it offers a digital out and an analog out proportional to the gas level sensed. I see the pot on the board which might be used to set at what concentration the DO changes from low to high. These sensors are not very accurate unless you have test calibrated gas samples and even then they don't hold constants very long. They also respond to other gasses.

I have no ide what the heater current is but I would not try to power it from an Arduino till I knew. I would power it on a bench and use a DMM to look at the analog signal out. Less any test samples of gas there in not much to see.

Ron

I am working both with the stand-alone high-concentration MQ131 sensor and a sensor module. My first attempt will be with a stand-alone sensor connected to a breadboard and Arduino Uno.

The datasheet of the sensor states "on load resistance(RL)which is in series with sensor. In order to make the sensor with better performance, suitable RL value is needed". Contributor Ostaquet had a 1M ohm RL and other sketches show a 10k ohm resistor.

Other MQ gas sensors call for a load resistor to measure the resistance of the sensor. Does anyone have a 'rule of thumb' on picking the RL on this sensor (and MQ gas sensors)?

Thanks!

BTW first post.

pylon:
Post a link to the schematics of that module or attach it to the post! If you don't have one yet, ask your vendor for one.

That's a wiring diagram and not the boards schematics. We need the schematics of that black board in your wiring diagram.

I know how to wire it but I need to know how to calculate the percentage of ozone and I want to know if I connect the sensor with an external voltage source it will give other measures than if I connected with Arduino
and which way is effective and why
I heard that when you calculate the molecules in the air percentage you use units Parts-per notation how to generate an equation that converts the analog values to PPM.(without calibrating tools)

I know how to wire it

but

but I need to know how to calculate the percentage of ozone and I want to know if I connect the sensor with an external voltage source it will give other measures than if I connected with Arduino
and which way is effective and why

If you know how to wire it, why are you asking us how to connect it?

You still failed to provide schematics of the used breakout board.

"Why are you asking us how to connect it"
I MEAN will the mq131 library give accurate results and do I need to connect the external power for more accurate results and

in mq131 library he uses the sensor and he connects it with 1MOhms and I have the module I think it has another resistor value than in the library diagram so it will not give accurate results

I HAVE changed some numbers in the library and I think it will work

thanks for all
for helping

I MEAN will the mq131 library give accurate results and do I need to connect the external power for more accurate results

Maybe. As you still failed to provide schematics of the board you use we have to guess what circuit it uses. My guess is that it provides constant power to the heater so I would recommend an external power anyway because otherwise the internal voltage regulator of the UNO may overheat.

in mq131 library he uses the sensor and he connects it with 1MOhms and I have the module I think it has another resistor value than in the library diagram so it will not give accurate results

Your board probably has a completely different circuit anyway. What resistor value does your module have?