Microcontroller Based System Design For (Airflow Meter) Control

Abstract

This research describes air flow measurement device based on microcontroller .The design of the air flow meter includes sensors which allow the microcontroller to measure three parameters – air velocity , pressure and temperature . The software compensates the measured air flow for both temperature and relative pressure. The air flow meter software is almost entirely written in BASCOM –AVR -1.11.9.0 . The program consists of a main program and six cases ( Air flow meter _set , Temp _set , Pressure _set , and input value ), ADC channel ( 0 ……..5) . The design also includes seven-segment LED displays and variable resistance to allow selective display of airflow, temperature and pressure. Airflow is continuously compared with a program-defined set point if the measured airflow exceeds the set point, an output relay will be energized. The percentage measurement error (% error) is calculated from the following equation : % error = %100(Qmt – Qref ) / Qref Where Qmt and Qref are the Airflow meter rates from the measurement being evaluated and the reference flow meter .