ULP Wireless Update

Building the BBC micro:bit

Building the BBC micro:bit

The BBC micro:bit project is inspiring the next generation of computer science engineers

The man behind the BBC’s ambitious educational project explains how fears of a coding skills shortage prompted the organisation to leap into action

The British Broadcasting Corporation’s (BBC) educational project to give every year 7 schoolchild in the U.K. a free programmable learning device is almost fully rolled out, with nearly one million devices already in the hands of their new owners. The devices, called “micro:bits”, are small (and wearable) boards equipped with a basic LED display, various sensors and buttons, and a Bluetooth low energy wireless chip with embedded ARM processor. The intention is to teach children the basics of programming with the hope of encouraging them into studying science, technology, engineering, and math (STEM) subjects and eventually pursuing careers in computer science. It’s a laudable aim, but how did this ambitious project come about?


Howard Baker was with the BBC’s education department, the team which drove development of the micro:bit. He explains that the initial idea followed a 2011 report from the U.K.’s worldwide renowned Royal Society.


The report identified a steep decline in the number of students studying computer science at university. The report also revealed that the students’ skill level when they arrived at university had steadily declined.


“[This was all happening] at a time when [future] jobs required more and more of these skills,” Baker says. “That’s thinking skills associated with computer programming or organizing things in a way that a computer understands. We’d stopped learning these skills.”


Repeating history

The current generation had no idea that programming skills were in demand in the U.K, Baker says. It came as a surprise to many schoolchildren that there is a strong British industry creating games and movies which represents an exciting potential career path for computer science and STEM graduates.


The U.K. government changed the school curriculum as a result of the Royal Society report, but BBC Learning felt there was more that could be done. The BBC has a history of getting involved with practical projects to educate its home country; in the 1980s, a similarly ambitious venture called the BBC Computer Literacy project placed microcomputers in U.K. schools to encourage young people to learn to use them. A basic level of computer literacy was seen to be extremely important to prepare the workforce for the impending microcomputer revolution.


Called the BBC Micro, the computer given to schools in the 1980s could be programmed using BASIC computer language and represented many people’s first experience of using a computer. It was a successful project and is believed to have kick-started the U.K.’s fledgling digital industries, in particular, the games industry.


“The revolution did happen, every home did have a microcomputer – computers are now ubiquitous,” Baker says. “The skills that we learned in the 1980s took us through the revolutions that followed very quickly after that. We were capable of building games, we were capable of coming up with the world wide web. But it was obvious [in 2011] that those skills were dipping.”


Baker’s Innovations team at BBC Learning started working with Manchester Metropolitan University, assembling panels of skills experts and teachers to discuss what form a potential educational project might take. Early ideas included a software version of the BBC Micro to teach basic programming. Kids loved the prototype, Baker says, but it was especially loved by parents who had used the original BBC Micro at school.


As this was happening, a new breed of electronics hobbyists called ‘makers’ — tech enthusiasts, engineers, and students — started to emerge. The rise of the Maker Movement coincided with the early part of the BBC Learning project and encouraged the notion that there ought to be a piece of hardware involved, that the kids could touch and play with, to make it feel more real. Some small smartphone- controlled robots were built as part of the project, which reacted to signals embedded in popular BBC TV programmes, and they were a huge success with children. This led to the Innovations team approaching the BBC’s flagship children’s TV programme, Blue Peter, with the idea of encouraging basic electronic assembly. However, the cost of materials for Blue Peter projects is limited to around GB£2 ($2.89), which meant that more expensive electronics projects weren’t appropriate.


“I was cycling home and thought: ‘what’s the cheapest, smallest thing we could put in their hands, what could we give them that would be a kickstart?’,” Baker says. “We’d have to be able to give it away, so it would have to be very cheap and it would have to have something on there that would immediately fascinate, like LEDs to write a message or make an animation. It needs buttons, an input/output to attach to a sensor, and it must be the easiest thing in the world to program. Like the BBC Micro - just tap in an instruction and the thing does it.”


Thinking bigger

The BBC micro:bit was born. A proof of concept device was made up by BBC R&D and trialed at various events with great success. But the project really gained momentum when newly-appointed Director General of the BBC, Tony Hall, announced that the BBC’s big educational project of 2015 would be “Make It Digital”, an initiative to, in his words, “get the nation coding again”. By then an integral part of this initiative, the micro:bit team realized they could, and should, think bigger. An initial idea to build 10,000 devices was scrapped in favour of giving a device away to every child in a whole year group – a million devices in total.


Towards the end of 2014, the Innovations team put out a call for commercial partners to help with hardware, software, learning resources, and finance. The partners worked together to finalize the spec of the device, which now included an on-board accelerometer and compass. U.K. IP vendor ARM developed and tested the basic hardware, technology Will Save Us designed the shape, look and feel of the device, and it was manufactured by distributor Farnell element14.


ARM designed the hardware with simplicity in mind. This included a high level of integration leading to the selection of a Bluetooth low energy chip with an embedded ARM processor. Nordic Semiconductor’s nRF51822 is the brain of the micro:bit combining the latest Bluetooth low energy, ANT+, and proprietary wireless technology with a 32-bit ARM Cortex-M0 microprocessor.


The nRF51822’s microprocessor is powerful enough to look after the wireless connectivity while also running the code written by the kids and looking after the board’s other capabilities (with the exception of the USB functionality which is supervised by an NXP Semiconductors microprocessor). The wireless connectivity allows a micro:bit to communicate with other micro:bits, and Bluetooth 4.0 compatible smartphones, tablets, and computers.


“We knew from working with ARM that we wanted an ARM Cortex-M0, but as soon as Nordic Semiconductor stepped up with a [Bluetooth low energy System- on-Chip (SoC) with an embedded ARM microprocessor], and showed it can do all this stuff we knew very quickly we’d solved most of the hardware problems,” Baker explains. “It was a brilliant solution; in one step, the micro:bit was equipped to do all the things it needed to do.


“Shake it and something happens, point it in a direction and something happens, tap it and a smartphone does something. That’s what turns the children on and underneath, Nordic’s chip is making it all possible.”


The other important chip on the board is NXP’s USB controller, chosen because it enables code to be ported to the board without first downloading a loader program (a potential obstacle to setting up the micro:bit). The company also provided the MEMS accelerometer and compass chips. The board also has 25 LEDs arranged in a grid, two buttons, pins to link to other sensors via crocodile clips, and an edge connector which can be used to connect to other hardware, such as Raspberry Pi or Arduino.


For the micro:bit’s software Microsoft volunteered its “Touch Develop” platform and built a web app around it, before adding Google’s Blockly language at Baker’s request.


Baker was also keen to include Python, a software language widely used in the teaching community, and with the support of the Python Foundation, a special version of Python for embedded devices was added. Code Kingdoms was responsible for the micro:bit’s Javascript editor, and C++ is also available through ARM mbed, the development environment used by many embedded engineers.


“The kids have a pathway where they can start with moving graphical blocks, like a jigsaw puzzle [in Blockly], then play with Python and Javascript, and then even move on to C++ on a clear pathway,” Baker says.


Key to connecting the hardware and software is a C++ library which implements the interactions referred to by the higher languages. This important library was built by Lancaster University; it’s now a fully fledged open-source embedded operating system with a range of functionalities that the various communities using the micro:bit can build on.


Since most schoolchildren are very familiar with mobiles, connection to a smartphone is a great practical illustration of what coding can do. Samsung built an Android app which allows the micro:bit to be programmed wirelessly by a smartphone, and some of the smartphone’s functions to be controlled by the micro:bit. Smartphones equipped with Bluetooth 4.0 and later can communicate via the Nordic nRF51822 SoC which hosts a specially written Bluetooth Profile and Services, courtesy of the Bluetooth SIG.


“Not only does Bluetooth low energy mean I can sit on the bus and write my program on my smartphone, and transfer it directly to the micro:bit, but I can also get the micro:bit talking to and controlling the smartphone,” explains Baker.


Get ready for the IoT

Although the micro:bits are almost fully rolled out to the first target group, this isn’t the end of the project. The micro:bit hardware is now on sale to the general public through Farnell element14 and several other retailers and there will be add-on kits available from partners like Kitronic which will incorporate additional sensors and other learning materials. the micro:bits might also eventually be able to transfer data between each other, using the nRF51822 SoC’s proprietary radio functionality.


Another potentially exciting development is that the BBC is working with Nominet (the U.K. web domain name registry) to get micro:bits connected to the wider Internet, using a Raspberry Pi or smartphone as a gateway. Internet connectivity will effectively make a million- plus micro:bits a genuine part of the Internet of Things (IoT). The micro:bits can then act as sensor or actuator nodes for the Raspberry Pi or smartphone, connected via Bluetooth low energy, a USB cable or through the edge connector.


“The micro:bit is not just a tool to help kids code, it’s a tool to help kids get ready for the IoT,” Baker says. His view is that comparable to the microcomputer revolution in the 1980s, the IoT is the next technology revolution our society faces. “The micro:bit is absolutely about building IoT technology, it’s about experimenting with building things for the new world, and having the opportunity to do that,” he says.