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Microbit

The Microbit is a tiny computer with built-in Bluetooth LE aka Bluetooth 4.0.

How to Install

go get -d -u gobot.io/x/gobot/... && go install gobot.io/x/gobot/platforms/microbit

You must install the Microbit firmware from [@sandeepmistry] located at https://github.com/sandeepmistry/node-bbc-microbit to use the Microbit with Gobot. This firmware is based on the micro:bit template, but with a few changes.

If you have the Gort command line tool installed, you can install the firmware using the following commands:

gort microbit download
gort microbit install /media/mysystem/MICROBIT

Substitute the proper location to your Microbit for /media/mysystem/MICROBIT in the previous command.

Once the firmware is installed, make sure your rotate your Microbit in a circle to calibrate the magnetometer before your try to connect to it using Gobot, or it will not respond.

You can also follow the firmware installation instructions at https://github.com/sandeepmistry/node-bbc-microbit#flashing-microbit-firmware.

The source code for the firmware is located at https://github.com/sandeepmistry/node-bbc-microbit-firmware however you do not need this source code to install the firmware using the installation instructions.

How to Use

The Gobot platform for the Microbit includes several different drivers, each one corresponding to a different capability:

AccelerometerDriver
ButtonDriver
IOPinDriver
LEDDriver
MagnetometerDriver
TemperatureDriver

The following example uses the LEDDriver:

package main

import (
	"os"
	"time"

	"gobot.io/x/gobot"
	"gobot.io/x/gobot/platforms/ble"
	"gobot.io/x/gobot/platforms/microbit"
)

func main() {
	bleAdaptor := ble.NewClientAdaptor(os.Args[1])
	ubit := microbit.NewLEDDriver(bleAdaptor)

	work := func() {
		ubit.Blank()
		gobot.After(1*time.Second, func() {
			ubit.WriteText("Hello")
		})
		gobot.After(7*time.Second, func() {
			ubit.Smile()
		})
	}

	robot := gobot.NewRobot("blinkBot",
		[]gobot.Connection{bleAdaptor},
		[]gobot.Device{ubit},
		work,
	)

	robot.Start()
}

Using Microbit with GPIO and AIO Drivers

The IOPinDriver is a special kind of Driver. It supports the DigitalReader, DigitalWriter, and AnalogReader interfaces.

This means you can use it with any gpio or aio Driver. In this example, we are using the normal gpio.ButtonDriver and gpio.LedDriver:

package main

import (
	"os"

	"gobot.io/x/gobot"
	"gobot.io/x/gobot/drivers/gpio"
	"gobot.io/x/gobot/platforms/ble"
	"gobot.io/x/gobot/platforms/microbit"
)

func main() {
	bleAdaptor := ble.NewClientAdaptor(os.Args[1])

	ubit := microbit.NewIOPinDriver(bleAdaptor)
	button := gpio.NewButtonDriver(ubit, "0")
	led := gpio.NewLedDriver(ubit, "1")

	work := func() {
		button.On(gpio.ButtonPush, func(data interface{}) {
			led.On()
		})
		button.On(gpio.ButtonRelease, func(data interface{}) {
			led.Off()
		})
	}

	robot := gobot.NewRobot("buttonBot",
		[]gobot.Connection{bleAdaptor},
		[]gobot.Device{ubit, button, led},
		work,
	)

	robot.Start()
}

How to Connect

The Microbit is a Bluetooth LE device.

You need to know the BLE ID of the Microbit that you want to connect to.

OSX

To run any of the Gobot BLE code you must use the GODEBUG=cgocheck=0 flag in order to get around some of the issues in the CGo-based implementation.

For example:

GODEBUG=cgocheck=0 go run examples/microbit_blink.go "BBC micro:bit"

OSX uses its own Bluetooth ID system which is different from the IDs used on Linux. The code calls thru the XPC interfaces provided by OSX, so as a result does not need to run under sudo.

Ubuntu

On Linux the BLE code will need to run as a root user account. The easiest way to accomplish this is probably to use go build to build your program, and then to run the requesting executable using sudo.