CH9-D - LED Matrix Countdown Timer

We'll use Maker Tape to connect the Button to the Bit Board on a LEGO baseplate.

We'll connect our Button to Pin 5 and to Ground (GND).

You'll notice the Ground on the Bit Board (as well as the LED and other Crazy Circuits components we'll use) is color coded White.

While some components have Polarity our Button does not. If you connect it the other way around it will still work fine.

If you've never used a micro:bit before you'll want to check out this guide: Bit Board V2 Setup and Use

We're going to load the following code for our LED Matrix Countdown Timer program: https://makecode.microbit.org/_6iL5HdFPb...

Our code will countdown from 5 to 0 and then clear the screen after two seconds.

You'll notice that there is a pause of 1000 milliseconds between the numbers decrementing...

We'll examine that in the next step.

Once the code is loaded it should start running immediately.

You can power the micro:bit via the USB cable you used to load the code or you can use a battery pack plugged into the Bit Board.

Press the button and you'll see the countdown on the LED Matrix go from 5 down to 0.

As mentioned, the code pauses one second between each number change, so we would expect the time between starting at 5 and seeing the 0 appear would be 5 seconds...

But we've noticed that when using the LED Matrix the micro:bit tends to run a little bit slower.

If you compare this 5 second countdown with a stopwatch or some other time telling device you might notice it takes longer than 5 seconds to complete our countdown.

In our tests the 5 second timer tends to take about 8.5 seconds to complete.

Follow along with our recorded Live Stream!

You can watch the full video of us walking through this project, along with explaining and exploring the code: https://youtube.com/live/geFYVuV-DI8