In this chapter, we will cover the following topics:

• What parts we will need to complete this project
• How to connect up the Scroll pHAT HD to our Pi Zero
• Installing the software to control our Scroll pHAT HD and writing our custom Python program for it
• Creating an off switch and an LED indicator for our Pi Zero, including writing the Python program for it
• Installing all of our electronics into our case and setting the Scroll pHAT HD up, so we can wear it as a badge

First off, let's look at what we will need for this project.

We will make use of the following things in this project:

• A Pi Zero W
• A Scroll pHAT HD
• An official Pi Zero case
• A portable battery pack
• A push button switch
• A micro LED board
• Various cables to connect our parts
• Cable terminal block
• A sticky-backed badge pin
• Cable shrink wrap
• A hot glue gun
• Solder and a soldering iron

First off, we need to connect up our hardware correctly so that we can begin to write our program to display our scrolling LED message! Let's first look at the Scroll pHAT HD.

As we are not using the female header to place the Scroll pHAT HD directly on top of our Pi Zero, we need to first find out which pins from the GPIO header of the Pi Zero are required to run the Scroll pHAT HD. Fortunately, we can quite easily access this information from the Raspberry Pi Pinout website at https://pinout.xyz/.

Once you have opened the web page, click on the Browse more HATS, pHATS and Add-ons link in the top-right corner of the page, and find the link for Scroll pHAT HD...

Before we can begin testing, our Scroll pHAT HD and see what we can do with it, we need to install some software to our Pi.

First off, we need to ensure that the I2C interface on our Pi is enabled. Start your Pi up and connect to it via SSH. Now that you are connected, run the following command on your Pi to access the configuration tool:

sudo raspi-config

Now, select 5 Interfacing Options using your cursors keys to highlight the menu option and then pressing Enter. In the Interfacing Options menu screen, highlight P5 I2C, and press Enter as shown in the following screenshot. In the next menu, select Yes and press Enter, and then press Enter to select OK to confirm the message that the ARM I2C interface is enabled. Press Tab twice to highlight Finish and press Enter to exit the raspi-config program. Now, type sudo reboot now to reboot your...

Now that we have a working scrolling message on our Pi Zero, we need to look a little more at the hardware and how we will use this as a badge we can wear on our clothes. The first thing you will probably be thinking is that the two bare circuit boards of the Pi Zero, and the Scroll pHAT HD with all their cables between them do not make the best badge you have ever seen! But fear not, as this section of the project will get everything looking far neater and ready to go as a badge.

We are going to solder two more pieces of hardware to our Pi Zero, which we will program to act as an off switch for our Pi Zero. This way, if we are using our Pi Zero out and about...

So, now we have all of our hardware connected up and tested and we also have our software written and tested, however we still need to carry out a few more steps to complete our project. We need to install our Pi Zero in its case and attach our switch and LED to the outside of the case, and we also need to enable us to wear the Scroll pHAT HD as a badge.

We are going to make use of the official Pi Zero case in this project. It has a really easy access to the GPIO pin holes on the board and is nice and compact too. If you have a different case, then you should be able to adapt these steps to use that case instead.

To start with, you will want to disconnect the cables...

In this project, we have looked at an add-on piece of hardware for the Raspberry Pi and the Scroll pHAT HD; we also saw how we can adapt this to work in our projects. You also learned about sources of information about how we need to wire these add-ons to our Raspberry Pi computers if we are not using the standard hat method; this will come in useful in future projects too!

We then looked at how we can control the Scroll pHAT HD add-on board with some simple Python code. There is plenty of scope here for personalizing this project here, and we now know where to find the online documentation to learn what else this board can do.

Another important step covered was to make Python programs we write start automatically when we power up our Pi Zero. We did this twice just in this project, and this is something we will need to do for most of the remaining projects in the book...