Portable, low-cost, Raspberry Pi-based optical sensor (PiSENS): continuous monitoring of atmospheric nitrogen dioxide.

We have developed a sensing system that utilizes a low-cost computer (Raspberry Pi) and its imaging camera as an optical sensing core for the continuous detection of NO in the air (PiSENS-A). The sensor is based on colour development as a consequence of the interaction of the gas with an absorbing solution. The PiSENS-A is thoroughly calibrated over the hourly mean which is used as one of the key metrics in evaluating air quality.