# Arduino Tutorial 41: Understanding Hexadecimal Numbers and Why They Are Important

In today’s lesson we discuss the topic of Hexadecimal numbers, and why they are important. As discussed previously, digital devices are nothing more than an incredibly large number of simple on/off switches connected together in clever ways to achieve useful functions. Since there is a need to represent numbers using only on/off switches, the binary number system is used. A switch that is in the on condition can be thought of as a “1” while a switch in the off condition can be thought of as a “0”. by stacking these switches side by side, we can represent almost any number by simply working with enough switches. As things got more complex, and the number of switches increased, it became untenable to keep up with all the 0’s and 1’s. Hence, groups of 4 switches were bunched together, and the Hexadecimal system was born. Understand Hexadecimal is simply a way to keep track of switches that is more convenient than the Binary system. This video discusses in detail, and gives lots of examples.

# Arduino Tutorial 6: Build an LED Binary Counter

In this lesson we take you step by step through how to build and program your own Binary Counter. In lesson 5 we showed you how to count in Binary, and how Binary numbers work. In today’s lesson, we show you how to practically implement a binary counter using the arduino and LED’s. We are using the elegoo kit, which you can pick up here.