Introduction to Robotics/Sensors/Lecture/Students

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Date: 09 / 29 / 2026
Sound Waves

Speed of sound

<math>D = Ct</math>

D is the distance, measured in meters.

C is the speed of sound in air, measured in meters per second.

t is the amount of time the wave travels, measured in seconds.

At 72°, sound travels at 344.8m/s.

Convert to Centimeters

We convert to centimeters because they are more useful, and it helps to remove fractions from our calculation.

<math>D = Ct \times \frac{100cm}{1m} = 100Ct</math>

For the BoeBot

<math>D = \frac{100CT}{2}</math>

Because the sound wave must travel to the object and back.

The BoeBot measures t in "clock cycles", which are each 2μseconds. We must convert the equation to use seconds instead of clock cycles:

<math>D = \frac{100Ct}{2}\times\frac{2}{1,000,000} = \frac{Ct}{10,000} = 0.03448t</math>

Fractional Math

The BoeBot can do some limited math with fractions.

The "**" operator is used as follows:

<math>A**B = A \times \frac{B}{65536}</math>

We calculate that:

We can use the following code to convert time to distance:

Distance = Conversion ** time

Finding the Conversion Constant

<math>Conversion = 0.03448 \times 65536 = 2260</math>