Tape measure is not essential to measure the distance between two locations. You can actually determine the distance using sound now. The traveling speed of sound waves in a gassy medium (such as air) is predictable and related to the temperature of the medium. Based on the calculated traveling velocity of the sound wave, you can figure out the distance between the two locations through the echo generated between the two locations. According to the velocity of the sound wave and the interval time between the original sound and its echo, you can figure out the distance.
- Identify the Celsius temperature of the medium (air). Use a thermometer to measure the temperature in the shade. If the thermometer displays temperature in Fahrenheit degrees only, convert it to Celsius according to the formula below: Subtract 32 from your Fahrenheit reading, and then divide the result by 1.8.
- Determine the traveling speed of sound wave according to the measured air temperature, using the following formula: 331.5 + (0.6 x T) = V. Where T represents measured air temperature in Celsius degrees; and V represents sound wave velocity in meters per second. For example, given the air temperature of 22.2 degrees Celsius, 331.5 + (0.6 x 22.2) = 344.82, as a result the velocity of sound waves is about 344.8 meters per second.
- You can convert the calculated sound wave velocity from meters per second to feet per second, by multiplying the result in step two by 3.281, as you prefer(optional).
- Record the interval time between the initial sound and its echo back to your chosen location. Make full use of your ultrasonic transmitter and receiver. Firstly aim the ultrasonic transmitter at a target object in a short distance; secondly send out a pulse and start stopwatch at the same time. Finally stop the stopwatch when the ultrasonic receiver detects the pulse echo. The transmission distance of different ultrasonic transmitters may be different, depending on their power capacity.
- Figure out the distance. As is well known, distance equals velocity multiplied by time. For that what you recorded is the time it took for sound to travel from your location to the target object and reflect back, so you should take the following formula: Distance = (Velocity x Time) / 2.
Tips & Warnings
The distance between two target objects can also be determined by an ultrasonic distance sensor through sound. An ultrasonic sensor not only comprises an ultrasonic transmitter and receiver, but will help you to conduct further calculations in the preceding steps.