BBC micro:bit review: The free Raspberry Pi rival every kid will love

Unveiled back in March 2015 as part of the BBC’s Make It Digital initiative, the micro:bit marks the corporation’s first foray into computing hardware since the much-loved BBC Micro in the 1980s. Unlike the BBC Micro, however, with its distinctive black-and-red mechanical keyboard, the micro:bit is a tiny device designed to be used with existing computers.

With an array of built-in sensors and a 5×5 LED matrix display, it’s designed to get kids thinking about physical computing and, following a redesign and some issues with the power circuitry, starting this month every Year 7 pupil in the UK is going to get one for free.

BBC micro:bit review: Specifications

It would be easy to make a comparison between the micro:bit and the Raspberry Pi, especially since the launch of the £4 Pi Zero. While both are low-cost devices designed for education, however, there’s a definite difference: the Pi is a microcomputer, a modern incarnation of the BBC Micro of old, while the micro:bit is a microcontroller.

The micro:bit is powered by a Nordic Semi nRF51822 SoC processor, which bundles a Bluetooth LE radio with a 32-bit ARM Cortex-M0 CPU running at only 16MHz and with just 16KB of RAM. Interestingly, this isn’t the fastest processor on the board. A second chip, a Kinetis microcontroller, has a 48MHz Cortex-M0+, which is only used as a bridge between the micro:bit and a USB-connected computer.

The micro:bit also includes a pair of onboard sensors in the form of a magnetic compass and an accelerometer, giving it basic positional and gesture-recognition capabilities. There’s a pair of buttons, plus a reset button at the rear, a 3.3V battery connector, and the front is dominated by a 5×5 matrix of 25 red LEDs – the only display available to the device.

BBC micro:bit review: Layout

Back when it was it was first announced, the BBC’s device shared the same characterful layout as the CodeBug, the device that inspired it. Since its redesign, though, the micro:bit has become much more businesslike. A tiny rectangle with rounded edges, the board measures not much more than a pair of SD card cases side by side.

The rear of the board, where the processors live, includes a silk-screen layer labelling most of its components. Oddly, though, the Kinetis microcontroller is left unlabelled. Flipping it over reveals the LED matrix and the micro:bit’s primary means of interacting with external hardware: a 25-pin edge-connector for general-purpose input/output (GPIO) operations.

Five of these pins are enlarged for use with crocodile clips or banana plugs, providing three input or output pins with analogue-to-digital conversion (ADC) and pulse-width modulation (PWM) support. This means they can do everything from reading data from moisture sensors to controlling a connected stepper motor or servo, along with a 3.3V and ground pin. The remaining 20 are slimmer, and designed for use with expansion boards such as the Kitronik Edge Connector Breakout Board.

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BBC micro:bit review: Programming

Unlike a Pi, where programming is done on the device, you’ll need an existing computer to program the micro:bit. The device arrives running a simple program to introduce you to the buttons, accelerometer and LED matrix. Connecting it to a PC is simple: plug it in via its micro-USB port and it appears as a removable drive, with no drivers required. The micro:bit is entirely cross-platform and compatible with any USB mass storage capable operating system.

There’s no need to install any development software, either. Programming the micro:bit is carried out in the browser on the BBC micro:bit website, using one of a choice of different code editors: Code Kingdoms’ JavaScript, Microsoft’s Touch Develop or the same company’s Block Editor – a child-friendly drag-and-drop environment that should be familiar to anyone who has used MIT’s Scratch.

A simulator is also available, for testing code without a physical micro:bit to hand. When compiled, code is downloaded as a hex file and simply dragged to the micro:bit’s drive to flash and run.

Python support is also planned, but at the time of writing was not available in the browser. However, those eager to play can write Python programs and install them on the micro:bit using uFlash, a command-line compilation and flashing utility compatible with any computer capable of running Python.

BBC micro:bit review: Bluetooth

The jewel in the micro:bit crown, though, is its Bluetooth support, which allows the device to be paired and programmed via a smartphone or tablet app. The app, developed in partnership with Samsung, is compatible with both Android and iOS devices.

When paired with a micro:bit – a process that involves noting down a pattern of LEDs and inputting a PIN that scrolls across the matrix – it’s possible to turn it into everything from a device for finding a lost phone to a remote control for music playback.

It’s even possible to use the micro:bit without access to a desktop or laptop. Code can be written in any one of the browser-based editors, saved to a user’s account, and then loaded into the app for wireless flashing to a paired micro:bit.

The process is slow: where flashing a simple program over a USB cable takes a few seconds, you can be waiting up to five minutes to flash the same program via Bluetooth. And the connection process can be finicky as well. It paired fine initially, but then disconnected and I had to delete the pairing and start again before it would work once more. I suspect that this is likely to improve over time, however, as the application is developed further.

BBC micro:bit review: Verdict

The micro:bit is an undeniably impressive project, with a huge amount of potential. It’s easy to get started with, a doddle to program, and thanks to the quality of the documentation and variety of resources available, it’s highly accessible. In other words, it’s perfect for its target audience: young kids taking their first steps in coding.

The big question, however, is the price. For anyone not receiving one through a school, the micro:bit will have to compete with everything from the £4 Raspberry Pi Zero to the £28 Genuino 101 and Raspberry Pi 3 (both devices that include Bluetooth), as well as the £15 CodeBug on which the micro:bit was originally based. As of yet, though, the BBC is silent on commercial availability and pricing.

See also: Raspberry Pi 3 review – built-in Wi-Fi and faster processor take the Pi to the next level