At a yard sale a few years ago I came into possession of a Lexicon MPX-100 Multi Effects Unit. I wanted to integrate this into my guitar rig and to do this needed a way to control it from my pedal. Using an Arduino, I programed my own MIDI pedal that sends the control signals needed to switch between presets and turn the unit on and off.
A few years ago I helped build some raised beds for a family vegetable garden. This was one of the first opportunities I had to apply the carpentry I learned in the scene shop to the outside world. As seen in the photos despite some flooding before getting things going the garden today is in full swing and graces us with tomatoes, beans, cucumbers, and a variety of other herbs and vegetables every summer.
What better way to understand your instrument than to build it? All of my electric guitars have been assembled, painted, and wired by me. This allows me a level of customization that would possibly cost thousands if bought from a name brand manufacturer. Instead I get to put my name on instruments that I love to play for a fraction of the price, with the satisfaction of saying "I built that." Another benefit is that I'm less scared to modify my instruments, instead I'll always be willing to swap something out or try something new just for the fun of it. By building my own gear in general, I have a better understanding of how to effectively utilize, and also repair it when needed.
In high school I was a member of FIRST Robotics Team 7036, The Roarbots. I started in my freshman year. In my junior year I become the head of electrical and pneumatic systems and the next year added team captain to my list of responsibilities. I learned invaluable skills for fabricating, troubleshooting, and solving problems on the fly. Working in the pits between matches and driving the robot on the field are some of my favorite experiences and I hope to be a part of team like this again one day.