Other companies that use the same principle shine broad-spectrum light and then filter it down and waste a lot of energy as a result, Weir said. Also filament/microheater-based sources take time to warm up and stabilize minimizing speed of operation. As a result, GSS can offer CO2 sensors that can be battery powered and sensors for applications where speed of response is key such as medical equipment.
In 2010, GSS Launched Cozir, claiming it to be the world's lowest power consumption NDIR CO2 sensor and in 2012 introduced SprintIR, which it claims is the world’s fastest response NDIR CO2 sensor. In last month GSS launched the SprintIR6S unit that can take 20 CO2 readings per second (see Sprint provides faster CO2 sensing).
So far so good, but does the applicability of NDIR absorption mean GSS will be expanding into detecting concentrations of other gases?
Weir said that with the number of applications for CO2 opening up rapidly that was not GSS primary goal. "Rather we want to make our components more application friendly."
GSS is already providing small PCBs in moulded housings to contain LED, photodiode, gas chamber and conditioning circuitry. Making sensors more application specific could mean the addition of additional physical features such as temperature and humidity sensing in some applications or the addition of microcontroller die and wireless communications such as ZigBee and Lora for IoT applications.
Weir acknowledged the possibility but said: "At present we are sensor component manufacturer. You have to ask at what point do you compete with customers."
Weir added that GSS, which employs 28 people, is already in the midst of a doubling of production capacity. It now has two epitaxial wafer machines installed at the West of Scotland Science Park northwest of Glasgow.
The epitaxial wafer machines allow the laying down of thin layers of highly complex compounds of aluminium, gallium, indium, arsenic and antimony of differing proportions, usually on a GaAs substrate. Doping is done with beryllium to form p-type regions and tellurium to form n-type regions (see A novel solid state non-dispersive infrared CO2 gas sensor compatible with wireless and portable deployment).
"One of the machines is for us exclusively and we rent time out on the other to academic institutions," said Weir. But this also means that GSS is in a position to cope with any uptick in business. Backend dicing and packaging is contracted out and then the components come to Cumbernauld for assembly and calibration.
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