Functions perfectly! The light sensor functionality is virtually flawless and the sound presets sound beautiful! It's really cool controlling the sound just by moving your hand closer or further away from the iPhone. You can also manually adjust vibrato and delay for added customization. In addition, they give you around 70 unique scales to choose from, and an option to just use the whole keyboard! It's one of my favorite apps!
Play with light – Theremin I/O turns your iPhone into a touchless music instrument. It uses your camera and flash to measure the distance to your hand, this signal is then processed by a synthesizer to generate a tone. Features: • Old-school synthesizer • Constrain input to scales (harmony quantization) • 8 sound presets with effect controls • 50+ scale presets • Use as a MIDI controller (requires in-app purchase) • Learn fast with the tutorial overlay For more information visit http://theremin.io