What are they?
Light Emitting Diodes (LEDs) are the most common thing you see when you want to add color to a project or when you see activity on a board such as the LED on the back of the Brainpad. The simple, and easiest to use LEDs have two ends coming from them, the shorter side that connects to ground, the cathode and the longer positive side that connects to a GPIO or power, the anode.
How do you use them?
The most common mistake when using LEDs is supplying power directly to the LED. This can result in the LED blowing up or worse, damaging the pin you are using. To prevent this, we will use a current limiting resistor to prevent this. Resistors reduce current flow (the power going to the LED) and are rated in Ohms ( Ω ). Anywhere from 330 Ohms Ω and 1K Ohms Ω is suggested. The higher the Ohms, the less power there is going to the LED resulting in a dimmer light but safer. It does not matter how you plug in the resistor as long as it connects the GPIO pin and the LED anode pin.
Where to get them
The most common and affordable LEDs can be found in bulk from around $5 – $15 USD. Common search terms on Amazon or AliExpress would be “LED diode”. Look for LEDs that match the picture above. Those that are included with Arduino kits or mention them will also work. LEDs are pretty small and can bend easily so it wouldn’t be bad to get a 100 piece kit.
For resistors, they will be around the same price and for searching, you want to include the Ohm rating suck as “1k resistor”. Same as LEDs, resistors are small and easy to lose or break so it is not silly to buy a package with a 100 or so in them.
What are they?
Unlike common LEDs explained on our other page, Smart LEDs are LEDs with tiny microcontrollers on them. There are tons of different configurations of these LEDs from strips, matrixes or rings but they are all the same when coding them.
If you want to learn more about LEDs and the many different types, you can read up on the Wikipedia page here.