MakeKit hover:bit User manual

Hover:bit
Coding the micro:bit hovercraft
makekit.no

2
Meet the micro:bit
Front Back
You can learn more at: https://tech.microbit.org/hardware/
micro:bit is a small computer with prosessor, sensors, display and radio. It
has connection pins for external components like LEDs, speakers or various
sensors.
Antenna
2,4 gHz
Reset button
USB Battery (3V)
Button BButton A
Screen (5x5 pixels)
Sensors
“Haircut”
“Gold teeth”

3
ART
Three values that controls the hover:bit
The Rule

Controls
ART
arm, roll, throttle
Variable:
Type
Minimum
Neutral
Maximum
Arm (start/stop)
Binary
0
1
Throttle (speed)
Percent
0
50
100
Roll (steering)
Degrees
-45
0
45
Arm starts and stops motors.
Roll controls the rudder and stearing
Throttle control the speed.
The values are being transmitter from remote control to the receiver (hovercraft)
These 3 values control the hovercraft:

Let´s code!

Start at makecode.microbit.org
Chrome is recommended for better connection with the micro:bit
Select “New project”.
PS. If you’re new to micro:bit you should try one of the tutorials above first.

Simulator:
Test your code here
On start:
Code that will run once at
startup
Code that will repeat
forever
Name your project
Download to micro:bit
Save a backup
Block
mode
Javascript
mode
Share your codeMain menu Settings
Undo zoom
The editor
Blocks

8
Name your project
Start by giving your project a name like “Sender group x”.
This is your unique radio channel. If you are alone you can use
channel 7
Sender group 7

9
Radio
1.Make a variable called radioChannel
2.Set the radioChannel to 7 (or a number between 0 and 255). This number must also be used on the hovercraft later
3.Use Show Number (in the forever loop) to å verify that Arm is changing correctly
4.Use the “radio set group” to make the radio channel take effect
1 2
3
4

10
ART
arm, roll, throttle
1.Make 3 variables called arm, roll and throttle
2.Use the button functions so button A makes throttle 10 (%) less, and button B makes it 10 more. Use “change”,
not “set”
3.Use the buttons A + B (a combination) to change the Arm between 0 and 1 everytime A + B is pressed
1
2

11
Arm
arm, roll, throttle
12
1.Put a Show Number (in the forever loop)
2.Use the simulator to test the A+B function (the number will switch between 0 and 1 and back)
3.Delete the same show number block when you have tested it. (use delete button or right click - delete)
3
Simuator

12
This is the code so far

13
Roll and rudder
We want to control the hovercraft´s steering by using the orientation sensor on the micro:bit. This is
called roll. This will control the rudder on the hovercraft.
Task: In the forever block, set the roll variable to the rotation roll. The block is called “rotation pitch”.
Drag it out and change it to “roll” by clicking the small triangle at the right.
This is what you should end up with:

14
X=0, Y=0
In the beginning of our code, our radio channel will be shown.
We want to use the display to also show our Arm, Roll and Throttle values as they change.
Before we plot, we use clear screen to prevent the screen to get filled with pixels.
Show arming
Find the forever-block.
Insert a clear screen block under the roll block.
Use the if-block to check if arm is not zero (armed).
If armed plot at coordinate 0,0 (or another place of your choice)
The display: Arm

15
The display: Roll and Throttle
We also want to show roll and throttle in the display. Use the blocks below to convert roll and throttle into values that can
be plotted on the screen. We want the throttle pixel to move upwards, starting at coordinate 0,4, then climb towards 0,0
We want the roll pixel to slide across the screen, from 0,2 (middle left) to 4,2 (middle right)
Show Throttle
Continue with the forever-block.
Insert a plot-block. In the y-section, insert a map block.
In the map block, insert the Throttle variable, then 0,100,4,0.
This will take a number between 0 and 100, and stretch it down to a number
between 4 and zero.
Show Roll
Continue with the forever-block.
Insert a plot-block. In the y-section, insert a map block.
In the map block, insert the Roll variable, then -45,45,0,4.
This will take a number between -45 and 45 (roll degrees), and stretch it down to a
number between zero and 4
0,0
Y
X
4,0
0,4
Throttle
Roll

16
Emergency stop
Make this little code to create a quick and effective way to stop your hover:bit. All you need to do is to shake your
controller and the motor will stop.
Shake to stop!

17
Test it!
Use the simulator (left side of make:code) to test
your code.
•Move the mouse cursor sidewys over the
micro:bit. Make sure the dot moves along your
mouse arrow. (Green span)
•Press B button numerous times. Verify that the
throttle is climbing upwards as in the blue span
•Press the A+B button to make the arming light to
turn on (top left on your screen)
•Press “Shake” to simulate a shake that will turn
off arm and make the throttle go down.Arm

18
To make our remote control work wirelessly, we need to
use the radio to transmit our ART-values.
They will be sent as separate numbers, with a little name
tag on them so the receiver can tell them apart.
Send the values over radio
Arm
Roll
Throttle
At the bottom of the Forever-loop:
• Use the radio send value = 0 block
• Make one block where you send the letter
“A” (must be capital) together with the Arm value.
• Do the same with Roll (R) and throttle (T)

19
Summary
This is the full code

20
1. Connect your micro:bit to the micro
usb
2. Microbit appears as a drive
3. Press “Download” and copy the file to
the MICROBIT drive.
4. Watch the orange light on the back
and make sure it flashes when code
is downloaded
Download the code
Read more about connecting the micro:bit See the micro:bit introduction at makekit.no/docs