The [[https://www.researchgate.net/publication/300918132_Using_BlueJ_to_Code_Java_on_the_Raspberry_Pi|RaspberyPi]] is great for learning Computer Science (as well as Engineering). If you already have a screen with a HDMI plug, a keyboard, and a mouse, you can can get started for less than $50--even less if you have a spare microSD card.  I got a [[https://www.canakit.com/raspberry-pi|Pi 3 Model B+]] in 2018 and started making some of the projects at [[http://www.bluej.org/raspberrypi/|BlueJ]] (which is already installed on [[https://www.raspberrypi.org/downloads/raspbian/|Raspian]]). Below are my adapted projects.

    -[[Getting The Wiring Right]]
    -[[Morse Code Code]]
    -[[Binary Counter]]

In 2022 I got a Raspberry Pi4 400. Unfortunately, it is so new, the old gpio -v gave me the message "Oops - unable to determine board type... model: 19"

I found some help at [[https://pi4j.com/1.4/install.html]].  I followed the "Easy Method" which produced the pi4j-core.jar file that I needed.  So that BlueJ finds it, I copied it over to the proper directory:

<code>sudo cp /opt/pi4j/lib/*.jar /usr/share/bluej/userlib/</code>

After that, I was able to plug in my breadboard, and all the old code in the labs listed above worked like a champ!