Around 339 million people are suffering from asthma worldwide. An acute asthma attack causes difficulties in daily life activities and sometimes it can be fatal. The unnecessary challenges faced by asthmatics signifies the need for a device that helps people monitor and control asthma to prevent possible attacks. A number of studies have reported an elevation of carbon monoxide in exhaled breath (eCO) of asthma patients and suggests it as an effective bio-marker of lung inflammation. By making use of the reported results, this projects aims to make use of the eCO bio-marker to design a carbon monoxide (CO) asthma monitoring system. The system consists of raspberry Pi 3 microcontroller and a MQ 7 CO sensor for processing and detecting the carbon monoxide concentration in parts per million. For accurate results a face mask is attached to the sensor to neglect the environmental CO. The working of the sensor circuit is validated using carbon monoxide source. With more researchers on the threshold level of CO for an imminent asthma attack this CO sensor could eventually save lives and improves the standard of living while being an affordable and user friendly device for active lifestyle.