I've recently bought this sensor and initially I was reading low values of between <400 ppm - 500 ppm indoors, but after two days it has significantly increased. Indoor readings...

I'm probably too late but do you have the code for it in Python? I'm trying to make it work on a Raspberry Pi as well

Hello I would like to know if air currents and pressure affect the measurement of CO2 sensor. Thanks!

Hello! Is the MG811 sensor compatible with the Arduino 101 board?

used to measure the C02 in breathing, inhale and exhale, of an athlete breathing fast in an max effort test? I need to buy a sensor for this application, addition of an oxygen sensor and flow integrator... please answer, thanks

Hi! The MG811 sensor has a measuring range of 350 to 10,000 ppm, however datasheet characteristic curve shown 400 - 10000 ppm.
I would like to know what the equation in the section of 350 to 400 ppm.
Could you help me??

What "sampling rate" can be achieved with this sensor? Is it fast enough to be used in a V02max test device (i.e. measuring the C02 concentration of breaths, inhale and exhale, of an athlete breathing fast in an max effort test)?

Hello DFR team

What is the best why to calibrate this unit?

I have 2 units of this sensor and everyone of them is giving a different reading with 20% deviation.

Before general calibration I left each one of them connected to arduino uno with a 12v 2.5a ADC for 2 hours in a fresh and well ventilated room (400-450 ppm assumable) and only the turned the screw until the red led went off.

Problem:

After this process i connected the 2 units with 2 arduino uno and uploaded the sample code, these are the readings:

1- Unit one - less then <400 ppm | Unit two - 550-600 ppm.

2-I placed the 2 sensor units in a 3X3 meter room with 5 adult people.

3-The ppm started to move up - Unit one went from less then 400 up to 450 ppm | Unit two went up to 850 ppm.

4-We left the room and ventilated with fresh air for 2 hours.

5-The 2 Units readings went below 400 ppm.

6-The adult people came back to the room and staid for more than 1 hour.

7-Units gave reading less then <400 ppm and not like in section "3" (450 and 850 ppm), also after 2 hours in close room full of people.

8-The Units woke up only after i exhale on them with air from my lungs..

So actually i have here 2 problems:

1-Calibration is not good enough.

2-Units are not waking up after co2 drops from less then 400 ppm and climbing again.

**i did this procedure 4 times and the results remained the same

Please kindly advise :)

Best,

Ido.

Hi, this co2 sensor requires a large current. Could you check your power supply? It is better to add a external voltage to the sensor power port. Don't forget common GND.

What is the connector on this board? Does DFRobot sell those connectors, or cable assembly that could be cut in half?

HI, calculate code has been included in the sample code -2, please check the code comments

how many meters this sensor will detect please tell me.

i have co2 sensor mg 811, i just need a sensor board which is compatible for arduino UNO. please help.

It seems that the calibration device required to calibrate this thing is much more expensive than the device itself, to the point that it makes me wonder what is the point of buying your device? What is the point in selling it when it is not calibrated?

It isn't just a slight inaccuracy. It is a gross inaccuracy. When it tells me my room CO2 content is less than 1ppm, there is a serious problem.

Why can't they be calibrated as part of the QC process in the factory, rather than expecting each customer to have a commercial grade CO2 meter to calibrate it?!

I have connected this CO2 sensor to its own dedicated 5V 2A power supply, and I am reading in a steady output voltage (with the specified 8.5 DC gain) of 4.1V. The voltage required to trigger any response above 400ppm according the the formula is around 2.75V. In order for me to get my sensor to read anything above 400ppm I need to burn incense in an enclosed cup and cover the sensor with extremely high amounts of smoke, and the readings aren't high enough to correspond to the real CO2 ppm level.

If I extrapolate what the sensor output of 4.1V would be in ppm according to the CO2 curve provided in the sample code, my room is apparently less than 1ppm. I'm pretty sure there's a serious problem either with my sensor, or with the code. Has anyone experienced this? Any advice?

I would expect that my sensor should output something closer to 2.75V if 400ppm is considered to be the average ambient level.

I read somewhere that we breathe in air at 400ppm and breathe out at 4,000ppm. I guess that would be the crudest way to calibrate it and create my own formula to match these super high readings i'm getting, right?

Is the DC gain of CO2 sensor v1.2 still 8.5?

In your Wiki-DOC. You have defined a DC Gain:
/*/
#define DC_GAIN (8.5) //define the DC gain of amplifier

*/

Where did this come from?

it is necessary to have a 5V input,because the sensor already has a step-up transfomer . And its current consumption is very high, so generally it requires an external power supply for Arduino.

What is the accuracy of this sensor?

Hello, Will it be enough power if I connect this VCC and GND to Mega 2560 +5V and GND in the digital section?

Have you already found an explanation for this particular behavior? Since i'm experiencing the same