Rotation Sensor Video Lecture - Electronics and Communication Engineering (ECE)

It's important to remember
that the motor can do much more
than simply drive
wheels on a vehicle.
And that is because
it's equipped
with an internal
rotation censor.
The technical name
is tachometer.
And what it does
is, at any time it
stores a number which represents
the rotational position
of the motor in degrees.
So for example, let's say we
wanted to create a volume knob,
so we stuck a beam on our motor.
At this point, the tachometer
may read zero, let's say.
We'll pretend this
is the zero position.
And as we rotate our motor, this
number will update in real time
to tell us the
position of the motor.
So if we couldn't
even see the motor,
we could just be
looking at this number
and we could understand
where the motor is.
And if we rotated it back here,
again, it would update to zero.
And if we rotated it
all the way around,
the tachometer would read 360.
Now this is very cool, because
ignoring the whole motor--
let's pretend we're
the robot and we only
have access to this number.
Let's say this number is x, and
x will range between 0 and 360,
depending on the
position of the motor.
Now we could do something with
this value, whatever x is, such
as we could wire it
into a sound block
so that the sound block will
change its volume depending
on the position of the motor.
So let's do this
simple warm-up example.
First, I'm going to plug in a
motor to Port C on my block.
And now I'm going to grab
my rotation sensor, which
is under the input, of course.
And I will select the rotation
sensor so the settings come up.
First I'm going to
assign it to Port C.
And there's two things you
can do with a rotation sensor
block.
You can either set it to reset,
meaning when my program hit
this block, it would
reset the tachometer
to that zero point I mentioned.
Or it can be a
read block, meaning
I want to read a value from the
motor and do something with it.
In this case, I want
to read the value.
And I'm going to pass
it into a sound block.
So I'm going to grab
a sound output here.
And let's say I want
to generate a tone.
I'm going to change the tone
to be a tenth of a second.
And now I'm going to
wire a value in again.
If you make sure
to expand this, it
will go all the way
down to the bottom.
Read the degree reading
from the rotation sensor.
And we want to feed
it into the volume
input on the sound block.
So I'm going to take
my degree reading,
going to click, click
again, and connect them.
And now we have a
sound block which
is getting its volume from the
rotational reading on a motor.
And before I run this
I'm going to drop it
inside a loop to get some
dynamic behavior going.
So I'm going to go ahead
and run this program,
and let's see it in action.
[TONE SOUNDS]