In the healthcare sector, the importance of adherence monitoring has been continuously growing in decades, with the increased need for a reliable convenient electronic system able to detect and monitor administering routine of consumed doses during home treatment. Patients with cystic fibrosis (CF), a severe chronic respiratory disease, require continuous treatment to relieve symptoms. However, the adherence to medical treatment of CF is reported low. The non-compliance may cause low utilisation of drugs, increased hospitalisation, and progressive deterioration. A robust monitoring system becomes crucial to address adherence to the prescribed regimen, predict exacerbation, and evaluate the efficacy of dosed medicine. This thesis presents a developed electronic adherence monitoring system with a systematic study of inhalation detecting using a novel low power disposable electronic sensor module with limited memory, which shows advantages regarding computational demands and the accuracy of detection. The selected features are proven to be reliable with high accuracy and low computational complexity. The designed prototype is low-power and capable to work continuously during a 28-day treatment supplied by a thin bendable battery. The portable device can be attached to the target dry powder inhaler and provide effective adherence monitoring with the functionality of audio processing, motion detection, data storage, data transmitting, and a direct feedback system. With real-time recognition and fast decision-making system, it can recognise and record administering events, the date and time of occurrence, and the duration of inhalations with high robustness against the noisy environment. According to the result of user testing, the device is initially proved to be accurate on detection and duration measurement, and the volunteers described it as convenient to use. It shows potential to improve the quality of inhalation and adherence to medical treatment of respiratory diseases.