Lesson 5

Lesson Overview

Students are able to understand the function and how to connect a 3V micro servo motor.
Students are able to build a 3V servo motor circuit and program micro: bit to move it using event-based programming.

6.4.2 Describe the function of all hardware used in programming.6.4.4 Build the required program based on the flow chart made.6.4.5 Connect hardware for products that emit light, sound, and movement.

Did you know that the elephant's trunk is one of the most amazing body parts in the animal world?

The elephant's trunk has 40,000 muscles while the whole human body has only 639 muscles.

Hmm... what are the materials needed to build a movable elephant trunk?

Micro Servo Motor 3V

Motor that rotates according to a programmed degree of rotation (0 to 180 degrees).

All movements in an electronic system require a motor. Different motors allow different rotations and movements, for example, left to right rotation or one direction circulation. Different motors achieve different goals.

Think and Answer

The servo motor used in this lesson is the EF92A model. Can we use another motor? Why do we choose a motor that requires a voltage of only 3V?

Let's build a moving elephant's trunk.

Video 5: The Elephant's Trunk

Watch and follow this video to get to know how to build the moving elephant's trunk.

Materials needed to follow this video:

micro: bit + USB wire + 3V micro servo motor + connector wire + 3 alligator clips
Computer
Visit makecode.microbit.org
Color paper + cardboard

TIPS Challenge in the Video

Transcript

Hello world! Welcome back to microbit series. I am Alina
and today we will build an elephant and its trunk!
In the previous video, we had seen
how to use buzzer, push button
on the microbit board as well as event based programming.
For this video, we will introduce a new external component
which is servo motor! Before we begin, prepare
all the project materials first: colour paper, micro
servo motor 3V, connecting wires, 3
crocodile clips and microbit board.
Microbit can only provide 3V to power the motor.
As usual, use your creativity to build the body of elephant.
Make sure that the elephant's trunk is separated from its body.
Make a hole on the head of the elephant at its trunk.
Connect the wires with the servo motor. Orange colour
to white wire, red wire to red wire,
and brown wire to the black wire.
Insert servo motor into the hole.
Attach the servo's blade to the servo motor
just now.
Screw it tight and stick the blade to the
elephant's trunk.
Clip the white wire to pin 0,
black wire to GND and red wire to 3V.
In the MakeCode software, select and press the block "On button pressed".
Below the drawer "Advance", click at "Extension"
and then click Servo extension.
The "Servo" drawer will show up and pull out the block
"Set servo" and connect it to "On button A pressed"
Leave the pin P0 there as our servo motor
just now was connected to pin P0 on the microbit.
Change the first position from 90 degree
to 160 degree.
You can see that the servo's blade changes at the simulation window.
Click and pull out block "pause"
and set the timing as 500 milliseconds.
Change the next value to 30 degree.
Repeat the same blocks for the blade
to return to its original position.
Connect microbit to the
computer using a USB cable.
Press download on the software and
save the programming file into the microbit that was connected just now.
Observe what will happen to the elephant's trunk when the button
is pressed. How do we play the music
happy birthday when button B is pressed
and the elephant's trunk move to the right and to the left when
both buttons A and B are pressed? Discuss it with your teacher
and friends! Tidy up your project and try to arrange
the wires and microbit board so that they are not seen from the front.
Elephant project is done! Your challenge before proceeding to the next episode is:
try to change the position of
elephant's trunk
when the microbit is shaken.
How is that done?
Happy trying!

Practice in the Video

Ways to build the code.

End product.

After watching this video, it’s time for you to try out the assignments and challenges in the video, which are:

Move the elephant's trunk when button A is pressed.
Change the position of the elephant's trunk when the elephant is shaken.

👉CLICK HERE👈 to try it on makecode.

Read the lesson notes below to deepen your understanding.

How to connect Micro Servo Motor 3V

Connect the red wire to pin 3V on the micro:bit board, the black wire to pin GND, and the yellow wire to pin P0.

Connect batteries (2 AA batteries) to the micro:bit when you use a servo motor. Servo motor requires a higher power supply than what can be supplied by a USB wire through a computer.