THE BBC MICRO:BIT

      The BBC Micro:bit is a small, inexpensive, single board computer (SBC.)  In very simple terms, that means it can load and run programs, receive input, and control output.  A basic operation using the Micro:bit might look like this:

• First, I create a program on my computer.  This program will make use of a small button on the Bit for input and the array of led's on the Bit for output.  The program will look something like this:

when button is pressed (this is input)

turn on certain led's so that a heart appears (this is output)

• Next, I download the program to the Bit, using a cable or WiFi connection.
• Then, when I press the button, the heart appears

     In the image you can see the buttons (for my program I used the A button) and the led matrix.  This isn't too impressive, but you will see as you go through this course website, you can do a lot more with the microbit.  You can control robots, a weather station, and even set up a small network with two microbits communicating.  

The board.  

     Let's start with the front of the board.  That's the side shown in the image above.  You can see there are two buttons labeled A and B.  Those are ways to provide input to the Bit.  You can press A, or B, or A and B together - three ways to tell the program to do something.  You can also see a 5 by 5 matrix (5 rows, 5 columns) of light emitting diodes (led's.)  That's a way for the program running on the board to provide information in response to some input.  Just like the example above, press A and the Bit responds by lighting up certain led's to show a heart shape.  The bronze-colored row at the bottom of the bit is very important.  In this row there are 25 GPIO pins.   Five of them are labeled (0, 1, 2, 3V, and GND) and the rest are just the rectangular bronze bars, separated by dark lines.  GPIO means General Purpose Input Output, and that describes these pins pretty well.  They provide ways to get even more input and output for your program.  The buttons and the led's are nice (there are a couple more things on the back of the board as well), but with the GPIO pins you can connect all kinds of things - sensors, motors, power sources, buzzers, and so on.  Being able to connect to these pins is very important and I'll have an entire section about how that's done.

     Now, let's look at the back of the board.

     Most of the components are clearly labeled.  From the upper right hand corner moving to the left, we see the plug in for a power source, usually a battery pack with a couple of AA batteries, a reset button for restarting the program, a small led that provides information about the Bit's status (is it on, is a program downloading/running), a USB port for communicating with your computer, and the antenna for a Low Energy Bluetooth (BLE) connection.  The BLE allows you to connect with laptops, tablets, phones, and other Micro:bits.  Most sources state that the effective range for the Bit's wireless connectivity is about 25 feet.  Below the BLE antenna is the main processor - the brain - where programs are stored, and IO is controlled.  Below the processor chip, there are two more input devices: a compass and an accelerometer.  The compass provides directional input and the accelerometer lets the program know when the board is tilted or moved in a particular direction.  And across the bottom, we see the back of the GPIO pins.