A lighting desk and its monitors in a booth, the room washed red behind the screens

Project - Hardware & console integration

spotmon

A remote followspot system built in-house. Spot operators point a moving light by hand from a controller built out of a dead one, with manual control over pan, tilt, intensity and iris, and console control over everything else.

Arduino DMX512 ETCnet ETC Eos Magic sheets

The spot magic sheet showing intensity and iris faders beside the cue list, with the camera monitor at left and the stage below — The magic sheet on the right, the operator’s camera monitor on the left, stage below.

01 The operator’s station

A moving light you can point by hand

Not every venue has a followspot position. This system allows you to put a spotlight anywhere you can hang a mover and the operator wherever you have room.

How it works

The station is a modified Martin MAC 250+ with most of its internal components gutted. Using the two grips, the operator pans and tilts it exactly as they would a high-end remote spot. Absolute encoders on the pan and tilt axes read that movement with 12-bit accuracy, an Arduino in the yoke turns it into DMX sent to an ETCnet node, and the lighting network sends those movements straight to the mover's universe.

There is a fader on each grip, one for intensity and one for iris, and a camera on the live fixture feeds the monitor mounted on the head. The operator sees the spot on stage in real time, and can iris in or out as needed.

The remote followspot station: a monitor mounted on the yoke showing the stage from the fixture’s point of view, with a grip handle either side — The camera on the fixture means the operator sees the stage from where the light is, rather than from wherever there was room to sit.

The physical layout of the spot controller, while developed for the MAC 250+, there is nothing preventing it from being integrated into other decommissioned movers. — The physical layout of the spot controller, while developed using a MAC 250+, there is nothing preventing it from being integrated into other decommissioned movers.

ChassisMartin MAC 250+ head, mount and base, stripped and retrofitted

PositionTwo 12-bit SPI absolute encoders - 4096 counts per revolution - on the pan and tilt axes

BrainArduino Uno with a Conceptinetics DMX shield, running as a DMX master

Output16-bit pan and tilt as coarse/fine channel pairs, plus intensity and iris from the grip faders

VisionCamera on the live fixture, BNC back to a monitor on the remote head

DataDMX out to an ETCnet node which then feeds movement directly to the mover while passing intensity and iris through the console.

Wider view of the remote followspot station at the back of house — The station sits where there is a sightline, not where the light is.

Detail of the retrofitted hardware inside the yoke — Inside the yoke - encoders, wiring and the DMX run out.

02 Into the console

Three paths, and what the console keeps

ETC's ETCnet nodes are flexible enough that a standard DMX-out node can act as the receiver for the controller, routing each signal to the system that needs it.

Pan and tilt go direct. Straight from the station to the node feeding the mover. The lighting console never sees them. This also allows for the console to regain control of the movers by just disconnecting the DMX cables connecting the controller to the node.
Iris and intensity go through the console. The Arduino sends them into ETCnet nodes, the nodes direct them to unused universes, and Eos maps those values onto faders so the console treats the op's grip faders as submasters.
Everything else is controlled by the console. Color, diffusion, and whatever other functions the mover has are still controlled by the console allowing for precise repeatable control of the spotlights. The intensity's maximum is also controlled by the console and only inhibited by the faders, so the level is trimmed rather than capped.

Splitting the signal this way also means the movers can be handed back to full console control quickly, for events that do not need spot operators at all.

The magic sheet

Rather than a separate monitor application, the spot display is an Eos magic sheet - which means it is built in the same show file as everything else and needs nothing extra on the network.

It carries a fader for iris and one for intensity per spot, plus the state the op cannot read off a number: whether the spot is diffused or on a hard edge, and which character it is currently picking up. Both of those are driven by palettes, so changing a look is a palette update rather than a rebuild.

The Eos magic sheet showing Spot 1 intensity at 100 percent and iris at 44 percent beside a labeled cue list — Iris and intensity beside the cue list, so the standby is visible before it is called.

Spots get their own cue lists

Spot intensity and color run on cue lists of their own, separate from the main LX list. Keeping them apart means the entire spot look sits in one consolidated view instead of being scattered through a show's worth of cues - and it can be moved, retimed or rewritten without touching the rest of the design.

The magic sheet during Cagney the Musical, reporting the spot as diffused and named to a character, with the operator's camera monitor alongside — Palette-driven state on the sheet during *Cagney the Musical* - the spot reading as diffused, and named to the character it is on.

03 The fixtures

High End Systems Halcyon Gold

ModelHalcyon Gold, Ultra-Bright (HAL-G-UB-MI)

Output31,000 lumens, 6500 K native - the High Fidelity build gives 19,000 at 5800 K

Engine430 W LED, 50,000-hour rated life

Optics13-lens system, 6°-57° zoom, 16-blade iris, Trifusion frost

FramingFour-plane full-curtain shutters, 180° module rotation

GobosSeven rotating plus open, eight fixed plus open, dual prisms, animation wheel

ColorCMY and CTO variable down to 3000 K, seven-position wheel plus open

Movement542° pan, 259° tilt on absolute encoders

Control57 channels in standard mode, DMX512 or sACN, RDM

Physical668 W at 100-240 V, 28.1 kg (62 lb)

High End Systems Halcyon Gold automated framing fixture, front view — Product image courtesy of ETC / High End Systems.

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