Turning An LED On

Within this tutorial we are going to make an LED turn on using scratch and a Raspberry Pi.

Equipment You Will Need

  • 1 x red LED
  • 2 x male to female jumper wires
  • 1 x breadboard
  • 1 x 330 ohm resistor
  • Raspberry Pi
  • keyboard
  • Mouse
  • SD Card with Raspbian installed
  • HDMI cable
  • Compatible Screen
  • Power Supply

The Circuit

Lets build the circuit. Make sure you have your LED the right way round. The positive leg is the longer leg on the LED, this is represented by the bent leg in the diagram below:

LED Circuit

Code

The first thing we need to do is load scratch. To do this go to menu -> programming -> scratch.

  1. Once Scratch has opened click on the Events menu and drag a When green flag clicked block into the coding area.

  2. Next click on the More blocks menu.

  3. Next click on Add an Extension and double click on Pi GPIO Icon. This will enable the Raspberry Pi GPIO pin extension.

  4. Next drag a Set GPIO to block into the coding area and attach it to When green flag clicked block.

  5. Now click in the circle and type 18 (this is the GPIO pin we are using on the Pi).

Your code should now look like this Code

What The Code Does

  • When Green flag clicked This tells Scratch to run the code when the green flag is clicked.

  • Set GPIO To This tells the raspberry pi to turn GPIO pin 18 on, which is where your LED is attached.

Running The Code

Now that we have finished the code to run it click the green flag. You should now see the LED turn on, if you don’t go back and see where you went wrong.

Keep Having FUN while LEARNING!