Encryption Project Guide

Table of Contents

• 1 Overview
• 2 Plan
• 3 Program

1 Overview

By the end of section 3, students have constructed the Ledger Art Project. In lesson Lesson 4-1 (Binary), students learn binary and develop a communication protocol that maps the letters of the alphabet to decimal and then binary. In lesson Lesson 4-2 (Encryption), students use their binary communication protocol to create an encryption technique and add an encrypted message on their Ledger Art Project.

The Encryption Project is from Lesson 4-2 (Encryption), and uses five of the NeoPixels on the Circuit Playground Express to represent a 5-bit binary number. This guide will build on the Ledger Art Project described in the Ledger Art Project Guide, and will be written in the first person to make visible the design and computational decisions made in this individual project.

2 Plan

In order to create a 5-bit encryption for my message, I first needed to map the letters of the alphabet to decimal numbers. I filled out the 5-Bit Communication Protocol from Lesson 4-1 (Binary). In my protocol, I decided to make A = 1, B = 2, C = 3, … , Z = 26.

I then needed a message to send. Since my Ledger Art Project is built around the idea of being in nature, I chose nature as the message I wanted to send using the NeoPixels on the Circuit Playground Express.

Using the NeoPixel guide in Lesson 4-1 (Binary),

I then storyboarded the code using the student handout from Lesson 4-2 (Encryption) to make my message:

I was now ready to begin coding my project.

3 Program

Since NeoPixels have data stored for their brightness and color, I first created an on start block to initialize the colors I will use in variables and set the brightness to 255 (full brightness). I created a variable called on to represent a NeoPixel (bit) being on and a variable called off to represent a NeoPixel (bit) being off. One question might be why we need to create a color for off. No matter what, we will need to manually turn the LED off (which is Black). To make my project more interesting, I used a different color than Black for my off. Students can choose whatever they want. I decided to make the color cyan on and the color magenta off. Cyan is Red 0 Green 255 Blue 255 and Magenta is Red 255 Green 0 Blue 255. So I used the RGB block in the LIGHTS menu of MakeCode to create those two colors. I could have also used the preloaded colors in MakeCode, but I wanted something different for mine.

Having my variables set up, I decided to turn each letter into its own function. In this way, I could iteratively and sequentially test each letter on my Circuit Playground Express.

Having tested my code, I realized that it would be very difficult to know when the message starts and ends. So I created a function that has all five NeoPixels flash white at the end of the message.

At this point, I was ready to put it all together. I made a forever block and called each of the letter functions with a one second pause between them. I ended the message with the End Message function.

In order to clean up my code a little, I created a new function called Encryption Message and put all the code in there. Then my forever loop only had one line of code in it.

I downloaded the code to my Circuit Playground Express one last time, and this is the result!