Ultrasonic Temperature Sensor

Project

• Traditional temperature sensors suffer from radiant heating and temperature averaging.
• Measuring the air directly mitigates false measurements.
• Ultrasonics are used to measure the speed of sound and derive the temperature directly.

System

Methods

• The time of flight is found by finding the phase difference between the transmitted and received signal using correlation.
• A best fit parabola interpolates the correlation to find the peak.
• The peak value and the distance between the two transducers are used to calculate the speed of sound.
• The speed of sound and relative humidity give the temperature using an equation.

Conclusion

• Temperature measurement is possible by measuring time of flight.
• High ADC resolution is necessary for low error results.
• This method is advantageous in high accuracy applications.
• An FPGA implementation with a higher resolution ADC is the next step.