50000 PPM (5%) CO2 Sensors

SCD30

Sensirion SCD30 CO2 sensor; 400 ppm – 10.000 ppm

Sparkfun CO₂ Humidity and Temperature Sensor - SCD30

The optimal sample interval for power consumption is 15 seconds (see chart below). By default, the interval between two measurements is 2 seconds. Nondispersive Infrared (NDIR) sensor that measures 400 to 10000ppm with an accuracy of ±(30ppm+3%) Full measurement range is 0 to 40000 ppm. It also measures releative humidity and temperature. The automatic self-calibration routine requires 7 days of continuous readings with at least 1 hour a day of "fresh air". I2C address is 0x61; I2C SCL and SDA has internal 45kΩ pull-up resistor, pulled to 3V. Sensor lifetime is 15 years.

Connection to the sensor may be made with a Qqiic Breadboard Cable (yellow wire goes to the SCL pin), otherwise use the pinout labels to connect to your microcontroller via I2C.

After a 2 day burn-in (7 day recommended), I had an opportunity to test the SCD30 in an environment where the CO2 levels went from 400 PPM to 14000 PPM (14%). The graph below shows the performance of the SC30 versus this calibrated device. Both sensors were set to record a value every five seconds. The difference in the maximum value is only 2.2%.

Grove - Multichannel Gas Sensor

Detects carbon monoxide, nitrogen, ethanol, hydrogen, ammonia, methane, propane, and iso-butane.

Helium (He) gas

Most helium sensors are based on the "thermal conductive" sensing method.

SAFEGAS He sensor 4-20 mA output; Model YT-95H-He $1200/ea

0 to 1000 ppm

MGD-2002 H2 and H3 gas detector

NISSHNBO MoLeTELL helium gas leak detector 0.03 to 5% vol range

Nuvair Pro He Alarm (He 0 to 100%)

K522 TDC H2, He, Ar gas sensor $400

Sensors' Advanced Gasmitter (AGM22)

Useful references

Dräger's Guide to Portable Gas Detection

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