Introduction to Robotics/Sensors/Lecture/Students

Introduction to Robotics

Sensors: Lecture (For Students) (For Teachers) — Lab (For Students) (For Teachers) — Assignment (For Students) (For Teachers) — Quiz (For Students) (For Teachers)

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Date: 11 / 21 / 2024
Sound Waves

Speed of sound

$D=Ct$

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.

$D=Ct\times {\frac {100cm}{1m}}=100Ct$

For the BoeBot

$D={\frac {100CT}{2}}$

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:

$D={\frac {100Ct}{2}}\times {\frac {2}{1,000,000}}={\frac {Ct}{10,000}}=0.03448t$

Fractional Math

The BoeBot can do some limited math with fractions.

The "**" operator is used as follows:

$A**B=A\times {\frac {B}{65536}}$

We calculate that:

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

Distance = Conversion ** time

Finding the Conversion Constant

$Conversion=0.03448\times 65536=2260$