Digital Respiration Rate Meter – Block diagram Description

It uses a displacement transducers for sensing the respiration rate using IR transmitter and receiver as shown in the physical assembly. Inhaling and exhaling the air during the respiration leads to movement of a light weight ball up and down in a capillary glass tube. This movement is sensed with the help of IR transmitter receiver assembly of the sensing circuit and converted into pulses through the pulse generator. These pulses are counted for a minute using a counter. The respiration rate is displayed on a 3 digit display through the seven segment decoder/driver. Start switch S1 is used to reset the display to zero and enable the counter for a minute to count the respiration pulse. The gate pulse generator consists of a monostable multivibrator. When triggered by start switch, it generates gating pulse of one minute duration.