Hi, this year I attended the 2010 National Scout Jamboree. My troop's gateway theme was The Blue Man Group, so we built PVC pipe instuments for people to play when they walked through. On one side there were 8 large pipes and on the other 16 small pipes. I thought it was fun to just hit the pipes and make alot of noise, but I also wanted to be able to actually play a song. The only problem is that I'm really not that musically inclined. So I thought that it would be cool if the pipes could light up to tell you which ones to hit to play a song.
I decided to put LEDs and sensors (the sensors are only in the large pipes since the small pipes didn't make much noise) inside the pipes to tell when you hit a pipe. So you could select which song to play, I put a button panel ontop of the wood that was holding up the pipes.
I had to experiment with what I would use for the sensors. At first I thought that a piezo would be able to pick up the vibrations when you hit the pipe, but the pipes didn't really vibrate enough for the piezos to pick it up. So then I tried putting an infrared emiter and infrared phototransistor inside each pipe pointing out the end so that when you put your hand over the end (when you hit the pipe), your hand would reflect the IR and the phototransistor would see that. This method worked.
This is the main control board that has the atmega168, the analog multiplexer (for the sensors), and the digital multiplexer (for the buttons)
This is the relay board that turns on and off the lights in the small pipes.
This is the control board for the LEDs in the big pipes. It has 4 shift registers so that I am able to control each pipe individually.
This is the case for controlling the small pipes. The pipes are connected by CAT5 cables and every four share a cable.
This is the control box for the big pipes and button panel. These pipes are also connected with CAT5 cables, except each pipe gets its own cable.
This is the power supply for the electronics. Since we didn't have any plugs around to plug in a charger I put together an array of solar panels so it would charge during the day. I put a switch on the batteries to change if they were in series or parallel since to charge them they needed to be in series and to run the electronics they needed to be in parallel.