Measurement of rate of gas flow using optoelectronic technique

A simple and inexpensive device for measuring low flow rates of gas is described. Device characteristics are studied by passing air through it. A pivot system is used which undergoes deflection when air passes through the device. The deflection is measured using IR LED and photodiode combination. The photodiode output is calibrated in terms of air flow rate using a reference air flow meter. The device can be used to measure the flow rates of air up to 15 l/m. The device can also be used to measure the flow rates of gases by calibrating it with reference gas flow meter.