It was at this semester that our school's gifted class had a special course:

Use BBC micro:bit to power a 3D printed car.

But I didn't like the frame our teacher made for us (You know, type "BitCar Micro Bit" on Google and you'll see many things like that),

I WANT SOMETHING DIFFERENT!!!

So instead of making wheeled cars, I decided to make a tracked vehicle (also 3D Printed!)

The first picture is the thing I want to make.

All printable components of a moving model of a German tank called Maus. (World's most heavy ever made.)

Supplies

Steps 1&2:

A Tinkercad account.

Step 3:

1x(or 2x) of BBC micro:bit.
Code With Mu Python Script Editor By DFRobot Team. (Drives the BBC micro:bit.) (You can also use something else to control the TT Motors if you know how to.)

Step 4:

A 3D Printer.
1x(or 2x) of BBC micro:bit.
1x Driver Expansion Board for BBC micro:bit. (Such As This One) (You can also use something else to drive the TT Motors if you know how to.)
2x 3V~6V TT Motor Gearbox. (1:48 Gear Ratio, AKA Hobby Gearmotor in Tinkercad, can find it in Circuits>Components in the editing interface) (Again, you can also use something else to drive the TT Motors if you know how to.)

Step 1: Find Something for Editing

I found some 3D Maus models in the gallery.

But some of the models' exterior design is too simple, and delicate ones are single-piece, which is SUPER hard to split all components.

Eventually, I found the one in the first picture above. (Above This Step's Title)

It's exterior is not too simple, and it can be ungrouped!

So, I used that one as my template.

Step 2: Let's Create the Layout!

Step I: Shrink N' Disassemble!

Make it fit into the workplane.

Disassemble everything that needs editing.

(First Pic Above)

Step II: Digging

Dig holes in the turret and the body to make the motors can fit into it.

(Second& Third Pic Above)

Step III: Suspension

The suspension in the original template was strange. (Like The Fifth Pic Above)

The Sixth Pic is the way to add crossbars onto the left (and also right) body.

Eight crossbars in total.

They are going to attach the 8 wheels in The Seventh Pic.

Four of the wheels are attached to a block with a hole on it to attach the TT Motors and should be attached to the upper crossbars. (The Eighth Pic)

(In fact, there should only be 2 of them attached with that block but I still think Four is necessary)

Step IV: Track

The track is separated into tons of small pieces like The Ninth Pic.

The Tenth Pic is how should they look like: the wheel's spikes fit well in them, and they can be attached one by one.

(There are quite a lot of ways to attach them, like print a rod and two caps separately, and make the rod go through the holes between the little track parts and put the caps at 2 sides.)

(I prefer using a piece of iron wire to go through the holes and bend its both sides (a little bit like staples) because the printer isn't accurate enough to print such small rods and caps and I don't need any caps by doing so.)

Step V: Export

Export all the parts.

(I PUT ALL FILES ABOVE, USE IT URSELF :))

We'll print them out later.

----------------------------------------TINKERCAD DESIGNING ENDS HERE----------------------------------------

Step 3: For the Motor

In this step, we are going to use Mu Python Script Editor by DFRobot.

(Disclaimer: It's only a demonstration, not advertising.)

(You Can Get it from the link in the 'supplies' section.)

Connect the micro:bit to your computer.
Download the editor I mentioned.
Unzip all files until you see 'Mu 1.0.1.exe'.
Double click to run it. (If UAC pops up, just click yes.)
After the installation wizard pop up, do the installation.
After the software is installed, run the editor.
Choose 'Maqueen' in the 'Select Mode' box.
Type the script under the 'Scripts' section below into the editing interface.
Save the text you've typed as a .py file.
Click the 'flash' button above the texting area to flash the file onto the micro:bits.

Scripts:

from microbit import *

import radio

I2caddr = 0x10

def motor(directionL, speedL, directionR, speedR):

buf = bytearray(5)

buf[0] = 0x00

buf[1] = directionL

buf[2] = speedL

buf[3] = directionR

buf[4] = speedR

i2c.write(I2caddr, buf)

radio.on()

radio.config(channel=01)

while True:

if button_a.was_pressed():

radio.send('A')

if button_b.was_pressed()

radio.send(‘B')

msg = radio.receive()

if msg is not None:

if msg==A:

motor(0, 255, 0, 0) # left motor forward and left motor speed = 255, (1, 255, 0, 0) for left motor backward

sleep(1000)

if msg==B:

motor(0, 0, 0, 255) #right motor forward and right motor speed = 255

sleep(1000)

-------------------------THINGS ABOVE THIS LINE IS EVERYTHING THAT YOU HAVE TO TYPE-------------------------

Step 4: Print, Assemble and Make It Work!

(I don't have any pics for any real stuff I printed in this step because only my teacher has a 3D printer, and it's summer vacation in Taiwan ---> no politics involved here:))

1. Send the stuff we're going to print onto the 3D printer.

(Google yourself, it depends on which printer you have)

2. Print them out.

3. Align the three parts of the body like the pic above. Don't attach them now.

4. Put the wheels onto the crossbars. Remember, the ones with blocks should correspond to the upper crossbars.

Connect all track parts, put it onto the wheels to make it looks like a real tracked vehicle.

5. Put the TT Motors into the body, and insert their shafts (which are white rods) into the blocks' (rectangular) holes on the upper wheels. Then make it to be fixed on the body (Like the pic above, use glue or tape)

6. Connect the motors to the driver board and the driver board to one of the micro:bits. Ensure you have enough electricity supply for all components, and enjoy your time playing this remote-controlled tank!

(How to control: press button A to turn right, button B to turn left, press both to go straight forward)