Simple LED output
The Arduino Uno has an orange LED which is connected to digital pin 13.
You can control this LED by sending a signal to the pin. This is the
simplest exercise you can do because it only requires the Arduino board
itself and no additional components. You can load the sketch into the
Arduino IDE from the File menu:
File → Examples → 01.Basics → Blink
Note that a digital pin can function as an input or an output. As the
software developer, you must ensure that the very important task of
hardware initialisation is performed at the
start of your code. Here you say which pins you are using as inputs and
which as outputs. This is the job of the
1 2 3 4 5 6 7 8 9 10 11 12
Make sure your Arduino is connected and that you have selected the correct port.
Then, open the sketch and upload it to the Arduino.
You should see the onboard orange LED repeatedly coming on for one second and going off for one second.
See if you can do the following:
- Change the blink rate to once every two second (time the blinks to make sure)
- Change the sketch to send SOS in Morse code (∙∙∙ −−− ∙∙∙). Leave a long pause between each message.
Add some hardware
The onboard LED is connected internally to digital pin 13. If you also add an external LED on the same pin it will also blink at the same time with no changes to the sketch.
NB. Before making any hardware changes you should disconnect the Arduino from the computer.
Look at the circuit below, run the simulation and then reproduce the connections using your own Arduino and breadboard. If this is the first time you have used an LED, please see the component information page