Kitronik BBC Micro Bit move Mini Mk2 User manual

V1.0

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ASSEMBLING
:MOVE MINI
CODING
:MOVE MINI
1. ASSEMBLING THE PCB
7. ATTACHING ELECTRONICS
4. TESTING THE SERVOS
5. CALIBRATING THE SERVOS
6. ASSEMBLING THE CHASSIS
3. BUILDING THE WHEELS
9. DRAW A SHAPE USING JAVASCRIPT
TROUBLESHOOTING
10. GO ONLINE!
SUPPORT FOR
:MOVE MINI
CONTENTS
INTRODUCTION TO THE :MOVE MINI
SUPPLIED WITH THIS KIT
GETTING CONNECTED
THE BBC micro:bit SOFTWARE
PROGRAMMING THE BBC micro:bit
2
3
6
5
4
7
8
13
14
17
22
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24
26
30
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2. FLASH THE ZIP LEDs
The Kitronik :MOVE mini for the BBC micro:bit provides an introduction
to robotics. The :MOVE mini is a 2 wheeled robot, suitable for both remote
control and autonomous operation. A range of add-on boards can expand
the capabilities to include more advanced functionality. The included :MOVE
Servo:Lite board can also be used in conjunction with a BBC micro:bit to build
other movement based projects.
Kitronik have created custom blocks for the MakeCode coding environment,
these make it ultra simple to code your :MOVE mini. Give it a try by adding
the ‘Servo:Lite’ blocks from the Extensions tab in MakeCode!
8. CODE :MOVE MINI TO MOVE
:MOVE MINI PIN OUT

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SUPPLIED WITH THIS KIT
CHASSIS PANELS
ELECTRONICS FIXINGS
2x 1x

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GETTING CONNECTED AND FINDING
THE PROGRAMMING ENVIRONMENT
Using a USB to micro-USB type B cable, connect the BBC
micro:bit to a computer.
Code will be created on the BBC micro:bit website.
www.microbit.org

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THE BBC micro:bit SOFTWARE
The BBC micro:bit is programmed using a web based (internet access
required) programming environment which is found at www.microbit.org.
To save programs to access at a later date you will need to save the .hex
files you create (these files will be explained later in this booklet). To reload a
program the relevant file needs to be dragged on to the editor screen. If this
is the first time you have used your BBC micro:bit then please refer to our
getting started guide at www.kitronik.co.uk/microbit.
All of the experiments in this guide are based around the Microsoft
MakeCode and Microsoft MakeCode JavaScript editors. The Microsoft
MakeCode Block Editor is a very easy to use graphical editor. The Microsoft
MakeCode JavaScript editor is a text based programming language which
is ideal for slightly more complex programs. It is possible to convert a Block
program into JavaScript. This offers an easy way of progressing from Block
programming to JavaScript. Other editor options include the Python Editor.
Refer to www.kitronik.co.uk/microbit for tutorials based on this.

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‘download’ . This is where the program is converted into a format that the BBC
drive to transfer the code into your micro:bit.’ The message ‘Do you want to open or
save microbit-script.hex from microbit.org?’ will appear. Select ‘Save As’ from the
Next plug a BBC micro:bit into the computer via the
USB Cable. The BBC micro:bit will appear as a removable
drive on the computer something like this.
the folder where it was saved and ‘Drop’ it onto the MICROBIT removable
drive. A message will appear saying ‘Copying 1 item.....to MICROBIT’. At the
After a few seconds the download will complete and the BBC
micro:bit should now be running the program.
If it doesn’t you may need to press the reset button, which is next to the status LED.
GETTING A PROGRAM ON
TO THE BBC MICRO:BIT
Status LED.
Reset button.
It is very easy to transfer a finished program to the BBC micro:bit.
First of all select ‘download’ . This is where the program
is converted into a program the micro:bit can understand. This
is known as a ‘.hex’ file. If it has compiled successfully, it will
return the message ‘Download completed... Move the .hex file to
the MICROBIT drive to transfer the code to your micro:bit.’ The
message ‘Do you want to open or save microbit-script.hex from
microbit.org’ will appear. Select ‘Save As’ from the ‘Save’ drop
down menu and save the hex file to a folder for BBC micro:bit .hex
files.
Next plug a BBC micro:bit into the computer via USB. The BBC
micro:bit will appear as a removable drive on the computer called
‘MICROBIT’.
To download the .hex file to the BBC micro:bit ‘Drag’ the .hex file
from the folder where it was saved and ‘Drop’ it onto the MICROBIT
removable drive. A message will appear saying ‘ Copying 1 item......
to MICROBIT’. At the same time, the yellow LED on the back of the
BBC micro:bit will flash.
After a few seconds, the download will complete and the BBC
micro:bit should now be running the program.
If it doesn’t you may need to reset the micro:bit, which can be done
by using the switch at the top of the Servo:Lite board to turn it off
and back on again.
‘download’ . This is where the program is converted into a format that the BBC
drive to transfer the code into your micro:bit.’ The message ‘Do you want to open or
save microbit-script.hex from microbit.org?’ will appear. Select ‘Save As’ from the
Next plug a BBC micro:bit into the computer via the
USB Cable. The BBC micro:bit will appear as a removable
drive on the computer something like this.
the folder where it was saved and ‘Drop’ it onto the MICROBIT removable
drive. A message will appear saying ‘Copying 1 item.....to MICROBIT’. At the
After a few seconds the download will complete and the BBC
micro:bit should now be running the program.
If it doesn’t you may need to press the reset button, which is next to the status LED.
GETTING A PROGRAM ON
TO THE BBC MICRO:BIT
Status LED.
Reset button.

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1ASSEMBLING THE SERVO:LITE PCB
STEP 1: Use a small Phillips screwdriver to screw the five M3 machine
screws through the micro:bit and spacer into the nuts mounted on the PCB.
ZIP LEDs
Servo Connections
PCB Mounted Nuts
On/Off Switch
Spacer
Micro:bit sold separately

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FLASH THE ZIP LEDs
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STEP 1: Put batteries into the Servo:Lite PCB, and turn it on.
STEP 2: Connect it to a computer using a micro-USB cable.
STEP 3: Bring up MakeCode Blocks Editor (makecode.microbit.org).
STEP 6: In the search bar type
‘neopixel’, then select the ‘neopixel’
box.
STEP 4: In the toolbox towards the left of the
screen, select the ‘Advanced’ section.
Additional packages should appear below.
NOTE: This will load a set of blocks compatible with Kitronik’s ZIP LEDs,
which makes them really easy to code!
NOTE: Kitronik’s ZIP LEDs are compatible with Adafruit’s Neopixels.
STEP 5: Select ‘Extensions’.

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STEP 7: Create a variable and name it ‘Pixel Array’.
STEP 8: Create the following code.
New variable name:
Pixel Array
A variable is like a container which can store information.
This could be a number, a word or a piece of information
you want your program to remember.
WHAT THIS MEANS
This tells the micro:bit that Pin 0 is connected to 5 colour
addressable LEDs.
WHAT THIS MEANS

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STEP 11: Try changing the code to make a different colour.
STEP 10: Press A and get ready for the lights!
STEP 9: Name your program and download!
Plug the BBC micro:bit into a USB port then drag and drop the
The program will automatically run on the simulator. Click on the ‘A’ button on
the simulator to see the LED pattern. Click on ‘B’ button to clear the pattern.
When button A is pressed,
light up all the pixels red.
WHAT THIS MEANS
When button B is pressed, clear the
LEDs represented by the variable
‘Pixel Array’. This will turn them off.
WHAT THIS MEANS

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As well as addressing all the pixels at once it is possible to set them
individually, or as a group. The first pixel always has an address of 0 (see
diagram below).
STEP 12: Change the code under ‘On button A pressed’ to the following.
REMEMBER: To show a change you must use a block with ‘show’ in it.
UploadDownload
NOTE: To get the ‘range from’ blocks, you may need to disassemble the ‘set
range’ block.
You may also need to click on ‘More’ under the ‘neopixel’ toolset to access
the ‘set pixel colour at’ block.
0 1 2 3 4
STEP 13:
STEP 14: Press A and watch the lights!
Set the first two pixels to red,
the middle pixel to white and
the last two to blue.
WHAT THIS MEANS

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STEP 15: Create the code below.
NOTE: The ‘rotate pixels’ block shifts each LED colour onto the next LED.
When it reaches the end of the line, it goes back to the first LED.
UploadDownload
STEP 16:
STEP 17: Press A and watch the light show!
This code shows a colour changing pattern when button A is
pressed and stops when button B is pressed.
WHAT THIS MEANS

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BUILDING THE WHEELS
3
2x
STEP 1: Stretch the O-Ring round the wheel, this will act as a tyre for :MOVE
mini. Press fit the wheel onto the servo shaft and repeat for the opposite
side.

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TESTING THE SERVOS
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SERVOS
The continuous rotation servos used in the :MOVE mini are controlled in the
same manner as normal remote control servos. These servos are controlled
by a repeating pulse, whose width commands the servo to turn to a position.
For a normal servo, position is measured from the output shaft and used to
determine what angle the servo should stop at.
Because of component tolerances, we may need to set the centre point on
the :MOVE mini servos to ensure it will stop when commanded. This is done
with a trimmer, which is explained later on.
A continuous rotation servo is slightly different. Instead of the signal telling
the servo how far to move, it tells the servo how fast to move.
STOP
0 DEGREES
90 DEGREES
180 DEGREES
NORMAL SERVO
CONTINUOS ROTATION SERVO
SPEED:
DEGREES:

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STEP 1: Plug the servos into the Servo:Lite board.
The board connections are:
STEP 2: With both wheel servos plugged in, it is time to write some test
code. Set out the servos like below. This will allow trimming/calibration of
the servos. This means they will stop and travel at the same speed when
commanded.
BOARD
LOCATION
WHAT IT
DOES
WIRE
COLOUR
TOP GROUND BROWN
MIDDLE POWER RED
BOTTOM SIGNAL ORANGE

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STEP 3: Bring up MakeCode Blocks Editor (makecode.microbit.org).
STEP 4: Create the following code.
When button B is pressed both servos should turn clockwise (looking
from the wheel side).
When button A is pressed, both servos should turn anti-clockwise
(looking from the wheel side).
When buttons A + B are pressed the servos should stop turning.
UploadDownload
If they do not then the centre point trimmer will need adjustment. On
the bottom of the servo, there is a small hole. This is used to access the
trimmer.
STEP 5:
STEP 6: Test out the buttons.
SPEED:
DEGREES:

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STEP 1: Press buttons A+B,
Then with a small screwdriver (through the hole) gently move the centre
point trimmer until the servo completely stops. There should also be no
sound coming from the servos.
STEP 2: Once the servos are calibrated unplug them from the board and
detach the wheels from the servos.
CALIBRATING THE SERVOS
5
TRIMMER
NOTE: The diagram below shows how the number of degrees set in the code
relates to the speed of the servo.
STOP
SPEED:
DEGREES:

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ASSEMBLING THE CHASSIS
6
STEP 1: Slot one of the servos into the base plate
as shown to the left.
STEP 2: Slot one of the internal side
panels over the top of the servos. Drop
an M3 Nut into the T-Joint and secure in
place with a 16mm bolt. Ensure that the
nut is fully inserted into the joint before
tightening.
NOTE: During assembly take care not to overtighten the screws as this can
damage :MOVE mini.
STEP 3: Repeat Step 1 & 2 for the opposite side.

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STEP 5: Turn the assembly upside down,
align the smaller rectangular holes of the
side panels up with the protruding bars
on the base plate, and slot them together.
Drop M3 nuts into the T-joints, and secure
with the 16mm bolts.
STEP 4: Snap the pen mounting plate
in between the two vertical plates,
just above the servo. The servo cables
should pass out of the rear of the
chassis.
STEP 6: Repeat for opposite side.

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STEP 7: Add a wheel (built earlier) and screw the smallest servo screw
through the middle to secure it to the servo.