Optical Oxygen Gas Sensor


  • Factory calibrated, maintenance free
  • High accuracy, low drift
  • Long life, non-depleting
  • Fast response (t63 < 2s)
  • Low power consumption

Optical Oxygen Gas Sensor - FDO2

The Next Generation Oxygen Gas Sensor

Patents: US 10,495,619 / DE 10 2016 114 918 / (EP 3 282 244 pending)

The FDO2 oxygen sensor is a factory calibrated, robust, accurate, fast response, long lasting and almost maintenance free oxygen sensor for demanding gas sensing applications, e.g. for oxygen gas monitoring in glove boxes, portable equipment, exhaust gases, Mars rovers and more. Although the form factor is similar to conventional electro-galvanic oxygen sensors (oxygen fuel cells), the sensor operates on a completely different, an optical principle. The optical measurement is based on a propriatary luminescent sensor dye from PyroScience, which is sensitive to oxygen partial pressure. This principle is very robust and shows virtually no interferences to other gases. It does not deplete over time, unlike electro-galvanic oxygen sensors with their very limited shelf and operation life. Optics and electronics are hermetically sealed from the measured gas and the sensing surface is highly hydrophobic, so water droplets do not disturb the measurement. For typical indoor environmental conditions a 10 year operating life is expected.

The flow-through cell FDO2-FTC enables simple integration in a variety of gas-streams. The USB interface cable FDO2-USB comes together with a versatile evaluation software (more details under Accessories).

Outstanding Features

  • factory calibration
  • fast response time (t63 <2 sec)
  • low drift (typ. < 1% O2/year at 21% O2)
  • long life (> 5 years)
  • simple 1-point user calibration (e.g. at air)
  • wide measuring range (0 -100% O2, up to 200% O2 on request)
  • standard form factor (M16x1, Ø=28 mm)
  • ease of use (digital output of partial pressure oxygen)
  • integrated ambient air pressure sensor can be used for calculating %O2
  • reliability (e.g. tested and integrated by NASA in Mars Rover 2020)
  • highly hydrophobic sensing surface (water droplets do not disturb the measurement)
  • full RoHS compliancy (lead/Pb free)
  • simple communication interface (UART, command or broadcast mode)
  • low energy consumption (3.3V, typ. 8mA)
  • linearity over the full oxygen range and sensor lifetime


Comparison to Classical Electro-Galvanic Oxygen Sensors

  Optical Oxygen Sensor FDO2 Electro-Galvanic Oxygen Sensors
Life Time > 5 years typ. 6-24 months
Drift < 1% O2 / year at 21% O2 typ. 1% O2 / month at 21% O2
Time (t63)
< 2s typ. 10-20 s
Warm Up Time 3 min up to 30 min
RoHS Lead (Pb) free Most contain lead
Health Hazards No known hazards

Lead leakage hazard:
  • Acute oral, inhalation, dermal toxicity
  • Carcinogenicity
Potassium hydroxide leakage hazard:
  • Acute oral toxicity
  • Serious eye damage
Acetic acid leakage hazard:
  • Eye or skin corrososion

Output Digital output of calibrated oxygen units Voltage, must be calibrated by the user and converted into oxygen units
Temperature Compensation Oxygen readings are automatically temperature compensated. The patented construction of the FDO2 ensures very good compensation even during fast temperature transitions. Many galvanic cells are not temperature compensated.
The complete optoelectronics is hermetically sealed from the measured gas, due to the "contact-less" optical measurement principle. Hermetical sealing not possible, because the oxygen must enter the galvanic cell.


Common Applications

  • Monitoring of oxygen concentration
  • Incubators
  • Oxygen concentrators
  • Inert gas processing chambers (glove boxes)
  • Exhaust gas measurement
  • Inert gas monitoring
  • Portable equipment
  • Monitoring fruit ripening and transport

Everything needed for testing


Includes everything needed for testing:

  • Oxygen gas sensor FDO2
  • Flow-through cell FDO2-FTC
  • USB interface cable
  • Free software licence

Exemplary Setup


Extend the FDO2 oxygen sensor with the Modbus analog out module FDO2-EXT. This way a Modbus interface and analog outputs of the sensor reading can be utilized.

USB Interface Cable


USB interface cable for ealuation of FDO2, incl. versatile logger software for easy setup and calibration

Flow-Through Cell for FDO2


Additional flow through cell for the FDO2 oxygen sensor



Modbus analog out module for the oxygen sensor FDO2.


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