CO₂ sensor Forum Discussions

Hello,

So I have been collecting data for about 6 days on two Sensor2Go PAS CO2 boards connected to a couple of Adafruit Feather Boards. Both have been successfully recording readings continuously on 10-second intervals for that time period, with the values in the range I expected.

Out of nowhere, at a time when no one was around and no substantial changes occurred to either the microcontroller/sensor setup or the environment the sensor is in, the value coming from the sensor changed drastically. In a matter of 3 readings(20 seconds), the value went from 1176->1441->2527. 1176 is the expected and correct value at that time. This was in an empty office with a closed door and a continuously decreasing value as no one was around and it was after work hours. The values have continued to stay in this range(ppm>2000) since this occurred, although changing like it is reacting to the CO2 values in the air. I have included a screenshot to show the data change on a graph. 

Setup:

• Adafruit Huzzah32 Feather
• PAS CO2 Shield2Go
• Arduino Code+PasCo2 Library
• Reading using Continuous Mode

Debugging Attempts:

• Feather reset
• Feather program reflash
• Shield2Go power reset
• Shield2Go placed in ambient, outdoor air
• Shield2Go disconnected and placed in ambient, outdoor air

I verified that the reading was incorrect by using an additional CO2 sensor set up directly next to the incorrectly reading sensor. The other sensor detected values within the range of expectation.

I am looking for thoughts on why this may be occurring. Again, it was reading completely fine for multiple days and seemingly at random started reading incorrectly. 

Thanks!

Hi, I would like to ask how can I use the XENSIV PAS CO2 sensor with my ESP32 board. I have managed to make the sensor work using an Arduino board using the sample code and the library but I would like to use the sensor with my  ESP32-based board and I have not found any libraries for ESP32.

Any help would be appreciated. Thank you!

I am a bit lost after trying to find the issue for quite a while but getting nowhere.

I have an Adafruit Huzza32 ESP32 Feather and PAS CO2 Shield2Go board. The PAS CO2 library is installed in Arduino IDE, the examples compile and get programmed to my board. 

I have 5V power coming externally from a power supply to the Shield.

Feather 3.3v,GND are wire to Shield 3.3v,GND

Feather SDA(23) and SCL(22) are wired to Shield2Go SDA and SCL.

None of the examples are able to communicate with the Shield and when I run an I2C scanner on the Feather, it is picking up 0 devices on I2C. 

Any thoughts or ideas on what I am missing? 

Thanks!

Hello,

I have some communication errors with the Infineon XENSIV PAS CO2.

I can communicate with the sensor over I2C. Write to setting registers works and if I read them after for validation, the value is right. That all works until I will leave the idle mode.  Before entering the IDL Mode the status register (0x01) is 0x80, that means that everythin is ok.

If I write a 0x02 to the 0x04 register to begin continious mode, nothing happens and if I read the register after, the value is still 0x00. So I tried to start the single mode (write 0x01 to reg 0x04). After that the communication with the sensor is lost (sensor don't give me an ACK). So I have to unpower and power the sensor to communicate with him.

Unfortunately I haven't the USB eval board, because I'm a student and its too expensive for our project. So I can't test if the sensor is brocken.

Hello,

Hello,
Regarding "AN_2011_PL38_2011_134235", the initialization sequence is bellow.

But I'd like no to power on 12V for low power consumption during accessing the registers via I2C when the PAS CO2 doesn't measure CO2.
Is it no problem to access the registers via I2C on only 3.3V power on?
I heard that 12V is for only IR heater then I think no problem...

Best regards,
h_nakamura

Hi, Could you please tell me whether the schematic diagram of the LED driver circuit on the sensor is public? If possible, could you provide it for our reference?

Thanks!

Hello,

Please let me know the cause of the noise on the I2C line of the PAS CO2 sensor.

The circuit is same of the datasheet V2.0 Fig 6. We use it as the I2C mode.

There is no noise when no I2C control.

When I2C control is started as shown below, it occurs at intervals of about 10 seconds.

According to AN_2011_PL38_2011_134235 V2.0 Fig 17, it occurs similar noise when it's PWM mode.

It's not the same mode, but is this phenomenon related?

Best regards,

Nakamura

Hi everyone

Hi everyone

For used the I2C communication, the 2 pin (RX) and 9 pin (PWM) set to OPEN is should be no problem?

Thanks

yang