I finished all of the projects in the book but there were a couple parts I never used. I used the large blue capacitor, the one pictured in the center on page 6. But I never used the other two next to it.
On page 9, I used the transistor on the right, with the big metal plate, but I never used the other one in any projects.
So I have no idea what the point of those are, or why I have them.
Also, on project 7, I wanted to try modifying it, so that there was also an LED associated with each button, instead of just a sound. I tried using what I learned in the first project to add an LED to the breadboard, but I got some strange effects. The LEDs started working when I pressed the buttons, but the sounds stopped playing.
I took it apart because I don't really know what I'm doing yet, and I don't want to break something. Can anyone tell me how I can modify project 7 to assign an LED to each button? I thought it would be cool to have an LED light up every time a different button/sound was played. But I don't know enough to do it correctly myself yet.