Experiments with Apollo Design’s Right Arm – Part 1

This post is the first in a number of experiments with a pan & tilt yoke that I’m fortunate enough to have in my workshop to experiment with!

Although designed mainly to allow static theatre light fixtures to pan and tilt I think the Right Arm has many more creative possibilities and not only on the stage, think projectors, cameras, speakers, lasers, snow machines etc.  In later posts I’ll be using it to do everything from smooth moving time-lapse video to an automated follow spot that will actually track a person on stage!

The Right Arm is designed and built by US (Indiana) based company Apollo Design Technology who specialise in theatrical and architectural lighting products and accessories. This first experiment is actually a re-creation of a successful use of the Right Arm  that I unfortunately failed to document properly!

I first came across the Right Arm in a trade brochure that was lying around the Abbey Theatre control room about three years ago. I knew it would be very useful to me at some stage, I just didn’t realise how soon. As detailed in this post, I was brought in on the first ever staged production of Stephen King’s The Shawshank Redemption by Dublin, Ireland based theatre company Lane Productions. I was given about three days to create a projected version of an effect that involved a mechanical butterfly ‘flying’ from about waist high up to the grid (about 7m). The reason the original was being replaced was because it wasn’t convincing or controllable enough and it was a major set piece of the finale.

The digital replacement involved an animated 3D model of the butterfly, and a projector powerful enough to project a small butterfly over a huge area – we went with a Barco CLM HD8 – an 8k Lumen 1080p DLP projector. It all worked perfectly in the end (see original post for stressful moments!) but it was an expensive and very touring unfriendly solution due to size / weight / noise issues.

So when it was announced that the show would go to Wyndham’s theatre in London’s West End I wasn’t surprised to be asked if there was any other way to do it. Enter the Right Arm. My idea was to replace the large, powerful, expensive and loud projector with a smaller, lighter, cheaper & quieter one and mechanically move it around to make the butterfly fly! This is exactly what we did with Shawshank Redemption in the West End and it worked faultlessly for the full run of over six months.

The design of the arm itself makes it very easy to mount a variety of fixtures and objects to it. Apollo didn’t over complicate this at all and the resulting set of equally spaced mounting holes are really all that’s needed. The unit is constructed in heavy duty cast parts that are definitely built to last. It’s weight without a fixture attached is 12.7kg and it can carry a load of 17.1kg, which is quite impressive.

The clip below is a short clip show the Right Arm moving through part of it’s start up routine with a 2k5 lumen projector mounted to the arm. The Right Arm can handle a load of 18.1kg – once it’d properly balanced (more in this later) which opens up a lot of possibilities in terms of lamps, cameras, projectors etc. The range of motion of the Right Arm is 300° pan and 270° tilt, speeds are 180° in 6 seconds on both axes. In my photos and clips you’ll notice that the Right Arm is up-rigged from a bar – this is simply because I didn’t have a decent bar at height rigged so I put this floor stand together. I’m not entirely sure if it’s designed to be mounted like this – but it does make it more useful as a camera head!

This next clip goes through a basic pass of the butterfly projection – it is obviously scaled down in terms of room size and throw distance but the demonstration is clear. The Right Arm is controlled via DMX512 and it has standard 5 pin input and output. The software I’m using to control the Right Arm is custom software for this show and uses a USB / DMX interface to output DMX. The software synchronised the video playback from the projector with the motion of the Right Arm. It also allowed for the flight path of the butterfly to be very accurately and graphically defined – for example it was programmed to avoid a poster on the cell wall in the set.

The Right Arm can be used in 8-bit or 16-bit mode depending on the required accuracy and / or range of movement required. In 16-bit mode the motion is incredibly smooth – the two powerful stepper motors are obviously being micro-stepped in this mode but the quality construction of the unit definitely contributes to the smooth motion even at very low speeds. I have even started experimenting with shooting some HD video using the Right Arm – stay tuned for the next post!

Addressing the unit is pretty straight forward using the mechanical buttons and display:

I’ve noticed that this has been replaced with the addition of digital buttons and an LCD panel on the Right Arm 2. Care needs to taken when mounting a load onto the Right Arm bracket as it needs to be correctly balanced to ensure even weight distribution through the range of the Right Arms motion. A simple but robust feature handles this – the bracket can be slid toward and away from the tilt pivot  point. Together with the multiple mounting holes on the bracket, this allows the load to be mounted with it’s centre of gravity in line with the two axes of motion.

Another indication of the build quality of the Right Arm are details that are often over looked. For example the stress relief boots on the cabling to the unit are of the right size and stiffness to properly protect the cables from wear and tear and life on the road. Also visible in this image is the rail (not sure what it’s actually called) that’s cast as part of the body of the unit itself – it’s incredibly useful for cable-tying all sorts of cables on there, and care does have to be taken when doing this as the stuff that you mount on the arm will be moving!

More photos below and stay tuned for the automated follow spot!