Custom Motorized Platter Controller

Questions
1

Hi Algoriddim Team,

I’m developing a custom motorized turntable controller for djay Pro (ios) and would like to understand the capabilities of your MIDI implementation.

The controller uses a high-resolution rotary encoder that tracks the absolute platter position and speed. My goal is to achieve accurate scratching and pitch control similar to a motorized DJ platter.

Could you please clarify:

  1. Does djay Pro support custom USB MIDI controllers with high-resolution platter/jog wheel data for scratching?

  2. Can a custom controller send absolute-position platter data, or does djay Pro only support relative encoder messages?

  3. Are there any recommendations for implementing a custom jog wheel/platter for the best scratching performance?

  4. Does djay Pro support HID controllers for custom hardware projects, or is MIDI the only supported option?

  5. Are there any technical documents or guidelines available for custom controller development?

Thank you for your time.

1 Like
4

Hi @Polyura, I’ve confirmed the following with our engineering team.

  1. Yes, as long as it is MIDI class-compliant.
  2. Currently, motorized controllers cannot be user mapped. The required interactions are unfortunately too complex. You can mimic something using the absolute rotary mappings but it will not behave like a native implementation.
  3. Map three jog commands, then tune the feel:
    A. Scratch (no touch detection) for non-touch platters, or Scratch (CC) for touch-sensitive ones.
    B. Pitch Bend (CC) for nudging.
    C. Adjust Speed and Reaction (smooth = cleaner on slow moves; responsive = tighter) until it feels natural.
    D. Mapping jog wheels | Algoriddim Support
  4. MIDI only. HID protocol is not supported for custom hardware.
  5. There’s no public SDK or MIDI implementation spec for custom hardware — the MIDI mapping section of the user manual is the only reference. Mapping a MIDI device | Algoriddim Support

I hope that helps!

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6

If a custom MIDI controller sends high-resolution absolute platter position data from a continuously rotating motorized platter, will Scratch (no touch detection) use the platter position directly for real-time scratching?

7

Hi @Polyura, it will roughly work, but the data will still be processed as if it was regular non-motorized jog wheel. It’s not a 100% raw input right to the playback speed.

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9

Just to clarify:If my custom controller sends high-resolution platter position data over USB MIDI, will moving the platter backward cause djay Pro to play the track backward in real time for scratching?Or will djay Pro treat it only as a jog wheel nudge/bend command?Thank you!

10

It should behave like a normal jogwheel. As such, moving the jogwheel backward while in scratch mode the track will move backwards.

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