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. Author manuscript; available in PMC: 2015 May 1.
Published in final edited form as: Sens Actuators B Chem. 2014 Jan 18;195:171–176. doi: 10.1016/j.snb.2013.12.110

Figure 2.

Figure 2

Figure 2

(a) Pocket-sized CO2 sensor device. It has inlets and outlets that allow the detection and analysis of both breath and environmental air samples. The key-sensing element is a CO2 sensor chip, which can be inserted into or remove from the device. The device also features an electronic circuit for signal processing and Bluetooth for wireless transmission of data. (b) The sensor chip changes color from purple to yellow after exposure to CO2 and the concentration of CO2 is determined by measuring the change in intensity of transmitted light for the sensing element.