Flashing Light

Look around you for a second.

From your phone notifications to your TV... from M-Pesa shops to ambulances and police cars... tiny lights are everywhere.

They flash, blink, and shine to send messages, warn us, and grab our attention.

These small but powerful lights are called LEDs (say: ell-ee-dees).
LED stands for Light Emitting Diodes.

So, what makes LEDs so special?

• They are super bright
• They use very little electricity
• They come in many colours

That’s why you’ll find them almost everywhere around you.

But here’s the part most people don’t notice...These lights don’t just turn ON and OFF because someone flips a switch.

They are controlled digitally. A microcomputer code decides when the light turns ON, when it turns OFF, and how it behaves

And now, you’re going to learn how to do the same.

In the next sections, you’ll build your own flashing light using the UNDA Xplora and create a simple real-world project using craft materials.

But before you start building, let’s break it down into a few simple things you’ll explore:

Just like using a wall switch at home, we either allow electricity to pass or not thus turning the bulb ON or OFF.

An LED only turns ON when electricity flows through it, and turns OFF when that flow stops.

But instead of controlling it with our hands, we can use a computing device like the Unda.Xplora to create HIGH and LOW signals.

A HIGH signal means we are turning ON, allowing electricity to pass and a LOW means we turn off.

Controlling a light is not just about turning it ON and OFF.

UNDA Xplora also has a TIMER that helps us control when signals are sent and how long they stay active.

When we keep sending HIGH and LOW signals again and again, the LED starts to blink

Using the UNDA Xplora;

When this repeats again and again, the LED starts to blink.

Short timing creates fast blinking.
Longer timing creates slower blinking.

Now challenge yourself

See if you can answer the questions below about LEDs

Now that you understand how to switch an LED ON and OFF, and how to make it blink!

It’s time to put these ideas into action.

In this section, you’ll build your own flashing light project using the Unda.Xplora on the breadboard

As you build, pay attention to:

• How the LED switches ON and OFF
• How the TIMER changes the blinking speed

Then explore the Play Section and try different options like:

• Fast blink
• Slow blink
• Notification

Observe the patterns and speed carefully.

What changes?
What stays the same?
What do you notice?

Let's get started!

Once you are done building the project, connect the battery to the the battery connector and then plug it to the power port of your UNDA.Xplora to power it on. Remember you can also use a USB-C Cable to power up your kit.

Once your kit is powered on, go to the Project Menu Window and then upload the Flashing Light Project and open the Play Section. Try put the different options on the Play Section and observe what happens.

Once the project has uploaded and is running, you will first observe the LED flashing at 500 milliseconds ON and 500 milliseconds OFF. The LED is turned ON and OFF by these timing intervals, creating a simple, regular blink that repeats as long as the power is on.

In the Play Section, you can select different flash patterns to see how changing the timing creates different effects. These include Fast Blink, Slow Blink, Heartbeat, Ticker, and Notify.

For example, the Fast Blink pattern uses short ON and OFF times, making the LED flash quickly, while Slow Blink uses longer timing intervals, making the LED flash more slowly.

Other patterns create different visual effects using their own timing sequences:

• Heartbeat – the LED flashes in a rhythm similar to a heartbeat.
• Ticker – the LED follows a repeated timing sequence to create a ticker-like effect.
• Notify – the LED uses a distinct timing pattern to indicate a notification.

The timing of each ON and OFF period determines how the LED appears to flash, allowing the same LED to produce several different patterns.