iPhone Screenshots


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.


• 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

What’s New

Version 1.3

* Updated for iOS 11
* Network MIDI is now free!

Ratings and Reviews

hiuhhseee ,


I have no access to change sounds. The bottom shows up for half a second and then goes blank. Where do I change sounds? Pretty cool how it works though. It’s awesome. Just love to have other sounds.

KDKnopp ,

Awesome simulation!

The GUI is top notch. Way above other apps that try to mimic the theremin.

Very customizable and well worth the small cost.

Val79 ,

Issue with calibration

I checked, and my phone allows this app to use the camera, but it could never calibrate.

Developer Response ,

Hi, I know this is several years late but Apple just started allowing Developers to respond to reviews. If you still need help with the app send me an email at johan@yellowagents.com and I'll do my best to assist you!


FFFF00 Agents AB
18.3 MB
Requires iOS 8.0 or later. Compatible with iPhone, 9.7-inch iPad Pro, 9.7-inch iPad Pro Wi-Fi + Cellular, 10.5-inch iPad Pro, 10.5-inch iPad Pro Wi‑Fi + Cellular, and iPod touch.
Age Rating
Rated 4+
© FFFF00Agents AB
In-App Purchases
  1. Network MIDI $5.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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