Session 6: Make Your Robot Move!

Goal: Use what you learned in Sessions 1–3 — micro:bit programming, buttons, and motor control — to write a MakeCode program that makes your robot move in a motion pattern of your choice.

Requirements

Your final program must meet these three rules:

At least two functions — for example moveForward and stopRobot, or turnLeft and turnRight. Functions make your code reusable and easier to read.
At least one working button — even if all it does is act as an emergency stop (on button B pressed → stopRobot). You may use both buttons for more control.
A motion pattern — pick one of the options below (or propose your own to an instructor).

Choose Your Motion Pattern

Read through all three options, then pick the one that interests you most.

Option A — Wall Following

Drive the robot along a wall (or a line of boxes).

Button	Action
A	Start driving forward
B	Turn left or right (whichever steers the robot away from the wall)

How it works:

Place the robot next to a wall.
Press A to start moving forward.
When the robot reaches a corner or gets too close, press B to turn it away from the wall.
Press A again to continue forward along the next stretch.

Tip: You can add A+B as an emergency stop, or make B alternate between turning left and turning right each time it is pressed.

Option B — Predefined Pattern

Program the robot to follow a fixed route automatically — no button presses needed after starting it.

Ideas:

Drive around a table — forward, turn 90°, forward, turn 90°, repeat four times to make a rectangle.
Navigate the hallway — drive forward for a set time, turn around, and come back.
Figure eight — forward, turn right, forward, turn left, repeat.

How it works:

Use a sequence of function calls with pause blocks between them to control timing:

on button A pressed:
    moveForward
    pause 2000 ms
    turnRight
    pause 500 ms
    moveForward
    pause 2000 ms
    turnRight
    pause 500 ms
    ... (repeat for the full shape)
    stopRobot

Press A to start the pattern. Use B as an emergency stop at any time.

Tip: Adjust the pause durations to tune distances and turn angles. Shorter pause = shorter distance or smaller turn.

Option C — Button-Controlled Driving

Drive the robot entirely by hand using the micro:bit buttons — like a remote control.

Button	Action
A	Move forward
B	Turn left or right (your choice)
A+B	Stop the robot

Each button press triggers the action for a short burst (e.g., 500 ms of movement, then stop), so you tap repeatedly to steer the robot through a space.

Tip: You can use a variable to toggle between turning left and turning right each time B is pressed.

Part 1: Review Your Motor Setup

Your robot uses the Motor:bit Breakout Board. The pin mapping:

Function	Pin in code	What it controls
Motor M1 direction A	`digital write pin P1`	Left motor direction
Motor M2 direction B	`digital write pin P2`	Right motor direction
Speed (both motors)	`analog write pin P0`	0 = stop, 1023 = full speed

If a wheel spins the wrong direction, swap the 1 and 0 values for that motor’s direction pin.

Part 2: Build Your Functions

Open MakeCode and create a new project called My Robot.

Use Make a Function (Advanced → Functions) to create at least two of these:

moveForward

digital write pin P1 to 1
digital write pin P2 to 1
analog write pin P0 to 600

moveBackward

digital write pin P1 to 0
digital write pin P2 to 0
analog write pin P0 to 600

turnLeft

digital write pin P1 to 0
digital write pin P2 to 1
analog write pin P0 to 600

turnRight

digital write pin P1 to 1
digital write pin P2 to 0
analog write pin P0 to 600

stopRobot

analog write pin P0 to 0

You do not need all five — just the ones your chosen motion pattern requires (minimum two).

Part 3: Wire Up Your Buttons

Add button handlers based on your chosen option. At minimum you need one button that stops the robot so you can halt it in an emergency:

on button B pressed:
    call stopRobot
    show icon (square)

Then add your movement button(s). For example, if you chose Option A — Wall Following:

on button A pressed:
    call moveForward
    show icon (arrow north)

on button B pressed:
    call turnLeft
    pause 400 ms
    call stopRobot

Part 4: Test and Tune

Work through these tests in order. Fix one issue before moving to the next.

Test 1 — Straight line

Place the robot on a flat surface. Press A. Does it drive forward in a roughly straight line?

If it veers left → try reducing the speed or swapping wires on the left motor
If it veers right → adjust the right motor the same way

Test 2 — Turns

Test your turn function(s). Does the robot turn roughly 90°?

Adjust the pause duration after a turn call (shorter pause = smaller turn angle)

Test 3 — Emergency stop

While the robot is moving, press your stop button. Does it stop immediately?

Test 4 — Full run

Run your complete motion pattern in an open space. Does the robot complete the pattern as expected?

Extension Challenges

If you finish early, try one or more of these:

A — Add the IR Sensor for Obstacle Detection Connect your IR sensor from Session 2 to pin P8. Add a forever loop that checks the sensor and stops the robot automatically when an obstacle is detected:

forever:
    if digital read pin P8 = 0:
        stopRobot
        show icon (sad face)
        pause 500 ms
        turnLeft
        pause 400 ms

This turns your robot into an autonomous obstacle-avoider — combining everything from Sessions 1–3.

B — Speed Ramp Make the robot gradually speed up from 0 to 800 over 1 second using a loop that increases analog write pin P0 in steps of 100.

C — LED Feedback Show different icons on the micro:bit display for each state: an arrow for forward, a turning arrow for turns, a square for stopped.

D — Combine Options Already finished one motion pattern? Try a second one in a new project.

Key Concepts You Used Today

Applying prior knowledge: combining micro:bit buttons and motor control from earlier sessions into a working robot program
Functions: reusable blocks that make programs easier to read and modify
Button input: using physical buttons to control robot behavior
Iterative testing: testing each feature in isolation before combining them
Timing and tuning: adjusting pause durations to control distances and turn angles

Congratulations!

You have designed, built, wired, and programmed a working robot from scratch. You moved from blinking LEDs in Session 1 all the way to a robot that drives and turns on command — great work!