This is a quick guide on how to build your own smart car for the micro:bit. You can buy a lot of different smart cars, but this way you can customize it to your own needs.

One of the first thing I do when teaching micro:bit or arduino, is to make my students build their own smart car. Since schools are often poor and the students are going to be building new cars each year I have a focus on using as few and as cheap materials as possible, while still being able to recover as much material as possible.

I am using elecfreaks motor:bit here because it is cheap ($ 13.50), allow you to control additional servo motors, have build in buzzer and on/off button and supports both 3.3 volt and 5 volt sensors.

Once the lasercut material have been cut out, it should properly take you about 30 - 40 minuts to build the smart car.

Supplies

Materials

4 x M3 x 30 screws

4 x M3 x 8 screws

4 x M3 x 6 screws

4 x M3 Spacer (They are not really needed, but they make it look cooler

12 x M3 nuts

1 x Caster wheel

2 x Smart car motors

2 x TT130 motor

2 x Wheels for the TT130 motor

1 x 9 volt battery + baterry holder

A bit of wire. In two different colours if possible

4 mm plywood (170 x 125 mm should do)

A small piece of double sided tape

Tools:

Screwdrivers

Soldering Iron

Wirecutter

Lasercutter

Step 1: Download and Lasercut

Download and laser cut the file. When you become better at it you can start changing how the car looks and add more functionality.

Smart car.ai
Download

Step 2: Soldering

While your lasercutter is runing you can solder the wires to the motors. Use two different colour wires so you can recognise what wire go to where.

Step 3: Add Motors

We first want to connect the motors to the car. For that you need the two motors, 4 M3 x 30 screws, 4 nuts and all the wood parts.

It is fairly simple to screw it together. I would suggest that you have the nuts on the inside of the car. That makes it easier to screwthe screws in.

Step 4: Motor:bit

First take the four M3 spacers and 4 nuts. Use the nuts to screw the four connectors into the four holes closest to the wheels. Then use the M3 x 6 screws to screw the motor:bit onto the car.

Instead of using spacer and M3 x 6 screws you can also just use M3 x 8 screws and screw the motor:bit directly onto the car.

Step 5: Coaster Wheel

Take your M3 x 8 screws and 4 bolts and use them to screw the coaster wheel into the last four holes.

Step 6: Add the Wheels

The wheels are just pressed onto the motors.

Step 7: Connect the Wires

Strip the end of the wires and connect them to the motor:bit. Screw the two wires from the right motor into M1 + and M1 - and the two wires from the left motor into M1 + and M1 -. I place the red into + and the green wire into -.

Step 8: Connect the Battery

Screw the battery holder into the motor:bit. Black wire to GND and red wire to VIN. Then take your small piece of double sided tape and place it at the rear of the smar car and put the battery on top of it.

The smart car is now finished and ready for you to add your micro:bit.