SEN0219 IR CO2 sensor non-linear output

tamara.baji 2017-10-23 04:33:32 6091 Views7 Replies
Hello,
I recently bought "Gravity: Analog Infrared CO2 Sensor For Arduino SKU: SEN0219" and connected it to Arduino Uno according to the instructions provided on the Wiki site (https://www.dfrobot.com/wiki/index.php/ ... U:_SEN0219).
After performing a few test measurements in order to determine the sensor's accuracy compared with reference values, I noticed that the sensor is giving a pulse response, instead of an "Excellent linear output" as stated among the sensor's features. The descriptions on the official DFRobot site let me conclude that I am investing in a reliable sensor, which, obviously, isn't the case. I wanted to incorporate this sensor in one of my projects in which I need a precise determination of CO2 concentration.
Could you give me an advice on turning my sensor into a usable one (instead of a waste of money)?

SEN0219_test.png Download(0)

2020-11-07 23:09:59 How can be possible all of them are so uncalibrated and in the same way?
gargmukul121

2020-10-31 01:23:12 I have calibrated the sensor. This isn't an issue of calibration.

The issue is that this sensor splits out erroneous data about every 5 seconds but not every 5 seconds. The previous post (https://imgur.com/nNSD2V3) shows the same analog signal I'm getting (https://imgur.com/a/NCFtBYR)
The wrong data beginning corresponds with red lights at the 4 corners of the sensor under the white diffusion fabric lighting up.

Since the SEN0129 is essentially a MH-Z14A sensor with a DFRobot PCB on top of it, I also checked the MH-Z14A datasheet (https://www.winsen-sensor.com/d/files/MH-Z14A.pdf) but it had no information about this data problem or the red lights. Here's a picture of those red lights: (https://i.postimg.cc/yNkWyJsC/MH-Z14-A-Red-Lights.jpg)

What should I do? Is this sensor not reliable for Analog voltage measurement? smap77

2018-03-08 21:00:45 I have the same readings (around 1725-1740 ppm) inside home from a new sensor.
How can be possible all of them are so uncalibrated and in the same way?

What is the delay between two lectures? I'm using 10000 and no pulses in the readings.
with smaller delays, there are pulses. antti.k.risto

2018-01-22 16:26:48 Place it in a fresh air environment and run it for over 24 hours, the sensor will calibrate it automatically. robert.chen

2018-01-21 03:38:32 Hello,

I have the same problem with my SEN0219, recently received yesterday.
I used the wiki sketch.
First, the sensor is placed outside and after 30mn running, CO2 level is 900ppm average... Oh my God!!!! All my family's going to die

Second, i can notice regular pulse datas around 1300ppm/1400ppm in output as you can see from my Serialprint:
"
voltage:825.20mv 1328.13ppm
voltage:820.31mv 1312.50ppm
voltage:688.48mv 900.00ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:698.24mv 931.25ppm
voltage:693.36mv 915.63ppm
voltage:688.48mv 900.00ppm
voltage:678.71mv 868.75ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:883.79mv 1509.38ppm
voltage:834.96mv 1356.25ppm
voltage:830.08mv 1343.75ppm
voltage:820.31mv 1312.50ppm
voltage:683.59mv 884.38ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:688.48mv 900.00ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:698.24mv 931.25ppm
voltage:688.48mv 900.00ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:688.48mv 900.00ppm
voltage:869.14mv 1465.63ppm
voltage:830.08mv 1343.75ppm
voltage:820.31mv 1312.50ppm
voltage:820.31mv 1312.50ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
voltage:693.36mv 915.63ppm
"
So please, what's going wrong with DFRobot product !? Should i ask a refound? ted.doloir

2017-10-24 15:59:25 Are these data reliable? it seems that they are a little high, you can make a calibration manually until get some reliable data, after that if there are still some exceptional data, you can filter some and make an average data.
To calibrate the sensor manually, you can set HD pins which are 8 and 20 to 0V and keep them more than 7 secs. Before that, make sure the sensor working over 20 mins in a circumstance under 400ppm robert.chen