Within this tutorial we are going to use Scratch and a Raspberry Pi to make an LED blink on and off.
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
- SD Card with Raspbian installed
- HDMI cable
- Compatible Screen
- Power Supply
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:
The first thing we need to do is load scratch. To do this go to menu -> programming -> scratch.
- Once Scratch has opened click on the
Drag a block to the coding area.
Next we need a block. Connect it to the block.
Now click on the little black arrow and click the next/edit button. You should get a text box like this . In the textbox type gpioserveron and click OK.
Drag another block into the coding area and attach it to the block. Click on the black arrow and click on new/edit. This time type config18out and click OK.
Next we need a block. Attach this under the block.
We now need another block this time attach it within the block. Again click on the black arrow and edit/new. This time type gpio18on.
We now need a block. Attach this under the block.
Next we need another block. Attach this under the block. Click on the black arrow and edit/new within the text box type gpio18off.
we now need another block and attach it under the block. Click within the white space and change the 1 to a 2.
Your code should look like this
What The Code Does
- This tells Scratch to run the code when the green flag is clicked.
- This tells Scratch to interact with the GPIO pins on the pi.
- This configures pin 18 on the raspberry pi as an output.
- . This makes the code loop forever.
- This tells the raspberry pi to turn GPIO pin 18 on, which is where your LED is attached.
- This makes the code pause for 1 second.
- This tells the raspberry pi to turn GPIO pin 18 off, which is where your LED is attached.
- This makes the code pause for 2 seconds.
Running The Code
Now that we have finished the code to run it click . You should now see the LED blink on and off, if you don’t go back and see where you went wrong.
To stop the code click on the
Well done you have just made an LED blink on and off.