Project - Water Chimes
This started out with me creating a MIDI-Out shield for an Arduino, based on work by Mike Cook. I needed a way to test it, so I created a potential divider with two LDRs, and mapped the analog input value onto a range of musical notes and output it as MIDI. It worked okay.
I thought it sounded a bit like wind-chimes, so I did some programming to make it sound even more like chimes, by adding 'echo' with randomised decay and timing - as if the 'chimes' were continuing to hit each other.
As a member of HACMan, I was helping to create a separate project for FutureEverything 2011 which was held at Victoria Baths, but was worried that we might not have a working device in time. So, as a back-up plan I modified my chimes to work with water instead of light. Since then, it's also been exhibited at Brighton Mini Maker Faire in September 2011.
The container has a few inches of water in it, with an electrode at each end which pass five volts through the water. The edge of the container has a metal strip running around the top. The user touches the strip with one hand and moves their other hand through the water. The voltage of the strip is measured on an analog-in pin of an Arduino which detects where in the water the person's other hand is.
The voltage value is mapped onto a note value. This note value is played by the MIDI shield, and then passes through a software shift register to provide an 'echo' loop. Whenever a note reaches the end of the register, it is passed back to the start with a randomised reduction in volume, and played again (unless the volume is below a certain threshold, at which point it's removed).
Rather than spend money on a MIDI sound module to generate the actual sound, I bought a musical keyboard off eBay for £1, and removed the circuitboard. I had to solder on a new 'power' button, but otherwise all the functions such as changing the voice are handled over MIDI. The MIDI lead was a 5-pin DIN lead off an old computer keyboard.
The speakers from the keyboard were removed and attached to the sides of the container. The container was placed on a small black chest of drawers with all the drawers removed and turned back-to-front, and all the electronics were stuffed inside in a waterproof box.
You can view a short video on YouTube of our projects at the event.