Microbit

The BBC micro:bit is a pocket-sized computer designed to make learning coding easy and fun. Despite its small size, it is packed with various sensors and inputs that make it an excellent platform for prototyping wearables and IoT devices.

A recent project we built was a Hamster Wheel Counter that tracks the number of spins and the temperature while our hamster runs at night.

Sensors & Inputs

The hardware differs slightly between the original V1 and the updated V2, with the V2 adding significant sensing capabilities.

Standard Sensors (V1 & V2)

• Accelerometer: A 3-axis motion sensor that detects movement, shaking, tilting, and free-fall gestures.
• Compass (Magnetometer): A 3-axis magnetic sensor for detecting direction (North) or magnetic field strength.
• Temperature Sensor: It doesn’t have a dedicated thermal sensor component; instead, it uses the processor’s (nRF51/nRF52) on-die temperature sensor to estimate ambient temperature.
• Light Sensor: The 5x5 LED matrix works in reverse to measure ambient light levels.
• Buttons: Two programmable physical buttons (A and B).

V2 Exclusive Sensors

The V2 revision added “sense” abilities without needing external attachments:

• Microphone: A MEMS microphone to detect sound levels and clap patterns (includes an LED indicator when active).
• Touch Sensor: The gold micro:bit logo on the face is now a capacitive touch sensor, acting as a third button.

Outputs & Connectivity

• LED Matrix: A 5x5 grid of red LEDs for scrolling text and animations.
• Speaker (V2 only): Built-in speaker for playing melodies and beeps.
• Radio & BLE: 2.4GHz radio for communicating between micro:bits or connecting via Bluetooth Low Energy to phones and tablets.
• Edge Connector: 25-pin connector (with 5 large rings for crocodile clips) for GPIO access (PWM, I2C, SPI, Analog).