Designing a respiratory CO2 measurement device for home monitoring of asthma severity

In this paper, a respiratory carbon dioxide (CO₂) measurement device has been designed and introduced for home monitoring applications. Typically, peak flow meter is used to monitor the severity of asthma. In order to use this device, the patient needs to inhale a full, deep breath in, and then blast it out as hard and fast as possible until there is no more air left to expel from his/her lungs. Besides that, children below 6 years old are unable to perform this test. Therefore, capnograph has recently been used as a new method to overcome such limitations. The problem is that capnographs in the market are too expensive, bulky, and not affordable to be used as a home monitoring device. Hence, in this preliminary work, we introduce a new and low-cost portable tool which utilize MG-811 sensor to detect CO₂. The output signal (concentration of CO₂) is then processed using Arduino and be sent to the PC through universal serial bus (USB) port for further analysis. In this paper, we present our preliminary simulation results that were obtained using Proteus 8 software.