Months ago the initial prototype OSBSS CO₂ sensor was designed and made in BERG lab, so as the next step we tried to verify the sensor’s performance. Therefore, as you can see in the following picture we performed a co-location test with OSBSS CO₂ sensor and two off-the-shelf CO₂ sensors. SBA-5 CO₂ Gas Analyzer and Telaire 7001 CO₂ Sensor were used for this reason. In order to record data, the off-the-shelf sensors combined with the Onset HOBO Data loggers. As the first attempt we launched all sensors with one minute intervals and placed them close to each other in the BERG lab for approximately 21 hours.

Results from the co-location test is shown in the graph below. From the graph it can be concluded that the overall response pattern of the OSBSS CO₂ sensor is exactly the same as SBA-5 and Telaire sensors. The second and third graphs are shown how well OSBSS CO₂ sensor correlate against 2 other sensors. The CO₂ concentration correlations looks great and there are consistent slops between OSBSS versus SBA-5 and Telaire sensors with R² values close to 1 for each. However, looking at the time series CO₂ concentration data, there are offsets of about 60 ppm CO₂ concentration for OSBSS sensor from both SBA-5 and Telaire sensors. From the previous experiments in BERG lab using SBA-5 CO₂ Gas Analyzer sensors it is revealed that although they are one of the expensive and accurate CO₂ sensors in the market, generally there was an offset of about 50 ppm between them. Therefore, in my opinion the result of our co-location is pretty encouraging. Next time I will built my own CO₂ sensor by following the tutorial and will test the performance of it as the further step