Before looking at the shiny new things, let’s take a quick look at what’s still the same. There’s still a 5×5 grid of red LEDs, and two buttons. There’s still an accelerometer, compass, and temperature sensor. The programming environments are also still the same, and code for your micro:bit v1 should work without alteration on a v2 board.
So, if all that’s the same, what’s new? There’s a significant boost to processing power, as the new Nordic nRF52833 microcontroller boasts a 64MHz ARM Cortex M4F (up from a 16MHz ARM Cortex M0+ in the previous micro:bit). There’s now 128kB of RAM and 512kB of storage. Bluetooth is upgraded from 4.0 to 5.0. For audio, there’s a microphone and speaker, and the logo at the top of the board is now touch-sensitive.
The GPIO connector is almost the same. It still has 21 GPIOs, with three broken out as large pads, and 3 V and ground connectors. However, the connector now has notches on each of the large pads. The notches in the GPIO connector may seem like a cosmetic change, but they do offer a significant advantage of making it easier to connect with crocodile clips or conductive thread. Clips can now go perpendicular to the board, and the notch will stop them from slipping sideways to bridge an additional GPIO.
The changes open up significant new ways you can work with micro:bit. Sound has long been a popular tool of teachers getting students interested in coding and, while the previous micro:bit could make sounds, you had to manually connect headphones using crocodile clips. Adding a speaker makes it a much simpler experience. The upgrade to the processor also brings machine learning within range. TensorFlow Lite can run on microcontrollers such as this, and the Edge Impulse team have already demonstrated keyword recognition from voice running on the new board (see here for details: hsmag.cc/EdgeImp).
The one major downside to the micro:bit v2 is, for us, the same as the one major downside to the micro:bit v1 – connectivity. There are three large pins broken out and this doesn’t really give you much scope for anything beyond adding a few buttons.
There are an additional 18 GPIOs available on the edge connector, but you will need an adapter to make this work. Of these 18, ten are needed for internal use – the LED array, buttons, and I2C bus are all included in this count, so even with an edge connector, there are relatively few connections available to use unless you disable these functions. There’s also no 5 V (or VBUS), so if you want to use hardware that needs this level supply, you will need an external power supply.
However, if you want to expand the capabilities of your micro:bit, there’s a good selection of add-ons available from a range of manufacturers. You can use your micro:bit to control a robot, water your plants, or play games – all by clipping it into off-the-shelf hardware. All these should continue to work with the new board.
For an educational microcontroller board, the advantage of the micro:bit really has nothing to do with the hardware – it’s the set of resources that go with this. Professionally made and curated projects and lesson plans can be found at microbit.org. These, on their own, are more important than the processor speed or amount of storage. The fact that the new device is compatible with code for the old micro:bit means that all the effort that went into creating them the first time is still paying off.
For a hobbyist, there are undoubtedly some great projects you can build with this board. However, if you need to use more than three GPIOs, you’ll end up with a bulky project, and even accounting for this, you’re still quite limited with connections. If you can live with this, the micro:bit version 2 represents excellent value for money.
For just over £10, you get a powerful microcontroller with a bunch of sensors and a couple of output devices (the LED array and the speaker). We don’t know of any other development board that offers so much for such a small price.
Cheap, powerful, and feature-packed, but limited connectivity.