Chapter: Camera Triggering¶
Overview¶
Camera triggering in Flair covers two distinct functions that are often confused:
- Trigger — a digital pulse (switch closure) that tells a camera to start or stop recording
- Sync / Genlock — an electronic signal that phase-locks the camera shutter to the robot's motion cycle (to eliminate frame rolling in slow motion)
This chapter covers trigger wiring, configuration, and troubleshooting. Sync/genlock is covered in the Sync Issues chapter.
Hardware Overview¶
DB37 Trigger Box (Bolt / RT14 systems)¶
The standard MRMC Trigger Box is a small relay box connected to the RT14 via a 26-way or DB37 ribbon cable.
| Feature | Detail |
|---|---|
| Connector | DB37 ribbon cable to RT14 |
| Power | 12V supplied by RT14 via ribbon cable |
| Outputs | 5+ relay outputs (12V switch closure) |
| Output 1 | Bloop light (by convention) |
| Inputs | 5 inputs (for external trigger-in) |
| Mimic ports | Yes — DB37 version has Mimic I/O |
| Requires Fast mode | All outputs require robot in Fast mode to fire |
12V chip in RT14 can be blown
The 12V supply for the Trigger Box comes from a chip on the RT14 board. This chip has no fuse protection and can be damaged by overcurrent from connected loads. See RT-14 12V Chip Blown.
Ethernet Trigger Box (Cinebot Mini)¶
A network-connected relay trigger box used with the Cinebot Mini. Acts as a RIC (Remote I/O Controller) node.
| Feature | Detail |
|---|---|
| Connector | Ethernet / network |
| Used with | Cinebot Mini |
| Mimic ports | No — Ethernet version has no Mimic I/O |
| Activation | Requires RIC line in flair.ini to be uncommented |
See: Ethernet Trigger Box — RIC Node Not Enabled
Bloop Light¶
A bright flash light mounted in the camera frame, used to mark the first frame of a move when precise sync is unavailable. Used in multi-pass compositing to align passes in post.
- Connected to Trigger Box Output 1 (by convention)
- Fires at a programmable frame number in the move
- Requires robot in Fast mode to fire
- Constant-dim glow (not firing) = noise on the trigger line — often indicates power ground imbalance
Key Concepts¶
| Term | Definition |
|---|---|
| Trigger | Switch-closure pulse from Trigger Box to camera to start/stop recording |
| Bloop | In-frame flash light triggered at a precise frame; used for multi-pass alignment |
| One Pulse | Flair trigger mode — single short pulse to start recording; used with Phantom |
| Pulsed | Flair trigger mode — used with ARRI Alexa Mini (different from One Pulse) |
| RIC | Remote I/O Controller — network node type for Ethernet Trigger Box |
| Fast / Slow mode | Triggers only fire in Fast mode. Slow mode suppresses all trigger outputs |
| Opto-isolation | Optical signal coupler that breaks the electrical ground connection between two systems |
| Back run | Robot running in reverse (negative frame direction); triggers at negative frames do not fire |
| Post-roll | Period after move completion; Flair waits here until the last trigger event is processed |
Trigger Mode Comparison — Camera-Specific¶
| Camera | Mode | Connection | Notes |
|---|---|---|---|
| Phantom VEO / Flex | One Pulse | BNC → Trigger Box | Above ~200fps: no sync, trigger only |
| ARRI Alexa Mini | Pulsed | Ulti-Arri cable → EXT-RS (K2.0006170) | 24V power required |
| Blackmagic URSA | BNC trigger | Trigger Box | BMPCC4K has no trigger input |
| RED (most) | Varies | Trigger Box or CTRL port | See Sync chapter for RED sync details |
| Generic / most cameras | One Pulse or Pulsed | Trigger Box | Test with a short pulse first |
Common Configuration Pitfalls¶
- Robot in Slow mode — all trigger outputs silently suppressed
- Triggers switch off — global trigger enable not active in Flair window
- Trigger event past end of move — causes long post-roll delay
- Negative frame trigger values — don't fire on back runs or in camera record mode below frame 0
- RIC not enabled in flair.ini — Ethernet Trigger Box doesn't activate
- Ultibox-routed bloop — needs manual Test click before Ready to Shoot
- LTC/trigger noise from mixed power — all devices must share same power source as robot
- Mains switching modern lights — digital ballast / LED fixtures may not behave like tungsten when power-switched; use DMX or a properly rated external relay.
Issue Index¶
Official Documentation References¶
| Document | Notes |
|---|---|
| Trigger Box QSG MRMC-1282-01 — printed p.2: ribbon cable routing | DB37 Trigger Box |
| Triggers Box Mk II QSG MRMC-1282-02 — whole document | Updated version |
| Bloop Light QSG MRMC-2174-01 — printed p.3: connecting cables | Bloop wiring and setup |
| Ethernet Relay Triggers Box QSG — printed p.2: outputs | Cinebot Mini Ethernet Trigger Box |
| Camera Sync and Trigger V2 | Combined sync and trigger overview |