TerribleSync

Use your iPhone or iPad to control the tempo of impulse-sync-enabled synthesizers, drum machines, and other music hardware.
Features:
• Tap tempo
• Supports 20.0 - 999.0+ BPM
• Rotary tempo dial for precise, tactile tempo adjustment
• Pause/mute button
• ?, !, and :fire: buttons to introduce character and chaos into your performance
• Clear, simple interface designed to be easy to use in a stage/performance setting
This app works with any instrument you own that takes voltage impulses as a tempo control, such as:
• KORG SQ-1, Volca, Monotribe, etc.
• Teenage Engineering Pocket Operator
• Moog MOTHER-32 (choose the "single clock advance" setting on the instrument)
This project is open source. Try building it yourself at https://github.com/terribleben/terrible-sync or contact twitter.com/terribleben with feedback!
Notes:
• 3.5mm audio cable is required to connect your iPhone or iPad to your sync-enabled instruments.
• If the instrument isn't responding, you may need to increase the iPhone's volume.
• This software is not produced by, endorsed by, or affiliated with KORG, Teenage Engineering, Moog Music, or other instrument manufacturers.