Investigate DJI Ronin/RS gimbal passthrough control

[erik-sutton95]

Goal

Investigate and add DJI Ronin/RS gimbal integration so OpenZCine can act as a unified Nikon camera monitor, camera controller, and safe passthrough control surface for a connected gimbal.

Why it matters

An operator using a Nikon Z camera on a DJI RS gimbal currently has separate control surfaces and apps for the camera and stabilizer. Bringing supported gimbal controls and status into OpenZCine would reduce app switching, keep the live image visible, and create a foundation for repeatable camera moves, remote operation, and role-based control from additional crew devices.

Proposed investigation

• Evaluate DJI's current RS SDK documentation, license, supported transports, and model/firmware matrix.
• Determine whether iOS and Android apps can communicate directly through an officially supported Bluetooth, USB-C, network, or accessory path, or whether an RSA/serial bridge is required.
• Validate coexistence with OpenZCine's Nikon Wi-Fi and USB-C camera connections without competing for session ownership or disrupting live view.
• Identify which gimbal state and commands are available, including axis attitude, motor state, mode, battery, position, rotation, speed, focus, and shooting controls.
• Determine whether Ronin buttons, joystick, front dial, or other physical inputs can be surfaced as assignable OpenZCine actions.
• Use protocol research beyond the published SDK only where it is lawful, security-conscious, and compatible with applicable licenses. Do not bypass authentication, extract secrets, modify firmware, or ship copied proprietary code.

Proposed experience

• Discover and connect a supported DJI RS gimbal from OpenZCine with explicit camera and gimbal identities.
• Show connection, battery, operating mode, axis position, and actionable fault or balance warnings where available.
• Provide a compact virtual joystick or direct-manipulation control for pan and tilt, with optional roll where safe.
• Add recenter, stop, and supported follow/lock mode actions without hiding the Nikon live feed.
• Let the operator set conservative speed, smoothing, axis, and movement limits before enabling remote motion.
• Keep an always-available emergency stop or dead-man behavior for any continuous movement.
• Preserve OpenZCine as the authoritative Nikon camera-session owner. Route record, focus, and camera-setting actions through one confirmed path so the gimbal and app cannot issue duplicate or conflicting commands.
• Allow selected Ronin hardware controls to trigger safe OpenZCine actions when the SDK exposes their events.
• Integrate with multi-device monitoring permissions so the host can grant a viewer gimbal control without automatically granting record or camera-settings access.
• Leave programmable A/B gimbal moves and coordinated focus/zoom/gimbal choreography as a later phase after basic control is dependable.

Success looks like

An operator can monitor and control a Nikon Z camera in OpenZCine, connect a supported DJI RS gimbal through an approved interface, view truthful gimbal state, and perform bounded pan/tilt/recenter actions without switching apps or creating conflicting camera-control paths.

Open questions

• Is DJI's published RS SDK usable directly from iOS and Android, or primarily intended for wired third-party hardware?
• Which current RS models, firmware versions, transports, and commands can be supported consistently?
• Can a phone maintain Nikon camera Wi-Fi while communicating with the gimbal over Bluetooth or another local transport?
• Are Ronin physical-control events exposed, or only outbound commands and state?
• How should OpenZCine arbitrate camera record/focus commands when a DJI camera-control cable or Bluetooth shutter connection is also active?
• What activation, account, App Store, SDK redistribution, and trademark requirements apply?
• Which safety constraints are required before any remote or programmable movement is enabled?

DJI references

• DJI RS SDK
• DJI RS 4 Pro connectivity and remote-control capabilities
• DJI Ronin series compatibility