This tutorial will cover those wonderful blinky things, LEDs. We’ve already talked and played with LEDs in Lesson #3 where we blinked some LEDs on and off, and also played with multi-colored LEDs to make a color-changing glowing orb. If you haven’t checked out that lesson yet, please do and go through the whole thing, OK? That way we can start off with some experience.
We’ll use this tutorial to re-visit LEDs in a little more detail. We’re going to cover how to calculate the current going through an LED and in the mean time introduce two important laws of electronics, Kirchhoff’s Voltage Law and Ohm’s Law. We’ll begin by performing experiments that will demonstrate how voltage and resistance affects current and then prove those results with a little math.
There’s no coding involved in this exercise, and although we use an Arduino in the images, you don’t need one to follow along. We do suggest some other kind of power supply so you can try out the experiments, but you can use even batteries in a battery holder!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.