Automated Fixtures - Auto Followspots

[LightingPenguin]

Can anyone tell me the current way to do an auto followspot? The other thread about this is 3 years old, so I feel like things have changed.

I'm not looking to use it in my school, just curious

[epimetheus]

I'm not sure how exactly it's done professionally, or even if it's done professionally, but if I were going about it, I'd use some sort of triangulation via radio receivers. Some classmates of mine did their senior design project in college on a similar system. They used multiple radio receivers to triangulate the location of a beacon. They wrote software that would interpret the receiver strengths and guide a robot to the beacon. I wouldn't be all that hard to do the same with followspots. Now before I get flamed, I'm not saying this is easy in practice. Conceptually, it's simple enough. In practice, the software is incredibly difficult in terms of filtering out noise and selecting the "clean" signal. As with any triangulation system, the accuracy improves with the more receivers you have, but at some point increasing the number of receivers becomes impracticle. Also, the more receivers you have, the more processing power is required to sift through all the data. If you can come up with a "clean" signal, converting that to DMX instructions for a moving head is probably one of the easier parts.

In my opinion, the hardest part of this concept is the data filtering algorithms. You've got to filter and determine a "clean" signal, at what, 40 times a second, to keep up with the DMX refresh rate. Honestly, I think this would make for a great electrical engineering design project (I wish I would have thought of it when I did mine), but in practice, it seems it isnt really used.

Someone please correct me on any of this if I'm off-base.

[derekleffew]

epimetheus, you've pretty much explained the Wybron AutoPilotII system, except that it uses ultrasonic signals instead of radio waves.

LightingPenguin, is this: http://www.controlbooth.com/forums/l...llowspots.html, the thread to which you are referring? Wybron, Inc. - Autopilot II remains the only viable solution. There are other threads on the topic. Most can be found by searching for "autopilot." When properly installed it works well, but can never replicate the nuances of a human operator, which is a large reason it has never gained widespread acceptance.

There was another company at LDI this past year. In the demo, moving lights were tracking a 2' diameter sphere suspended by three cables, and I believe the hoists were relaying via a computer position information to the fixtures. Anyone remember the company?

[LightingPenguin]

Thanks for the search term and answers, thats all the info I needed

[JChenault]

epimetheus,

There was another company at LDI this past year. In the demo, moving lights were tracking a 2' diameter sphere suspended by three cables, and I believe the hoists were relaying via a computer position information to the fixtures. Anyone remember the company?

I don't remember the company - but you are correct that it was reading the position of the winches - not some kind of sensor in the ball. It was a demo of how precisely they could read the position of the winches - not how they could track a moving object.

John

[epimetheus]

I think converting rectangular position information into DMX pan and tilt commands would be an interesting project. It's determining an object's position in real time that would be the difficult part.

[NickJones]

Way to much maths to bother. Think of all the calculations that would have to be done, you would have to write specialised software capable of outputting DMX and have sensors that somehow integrate with the software, if you are going to do it it would be way easier just to get an Auto Pilot thinggy.
Nick

[NevilleLighting]

I have to agree with Derek, still nothing out there that can match the nuances of a human operator. The other bad side (and maybe my information is out of date) is that once you have slaved a particular moving light to a particular transmitter all it can do is follow that transmitter. Maybe not a big deal of you have 200+ movers but quite a commitment if you have 4.

[jxgriffi]

I have to agree with Derek, still nothing out there that can match the nuances of a human operator. The other bad side (and maybe my information is out of date) is that once you have slaved a particular moving light to a particular transmitter all it can do is follow that transmitter. Maybe not a big deal of you have 200+ movers but quite a commitment if you have 4.

This is not true. I've been an Autopilot tech and designer on many shows. You can enable it for any light for any transmitter and the "box" takes over pan, tilt, iris (if enabled), etc. When you don't need it, you turn the channel off and the fixture behaves like normal.

For example....big move of all your movers ballyhoo-ing around...enable the channel and the selected fixtures dump down to the performer. Turn it off...they go back to the ballyhoo.

But I'm still in agreement...if an human operator can be used...it makes it much nicer. Autopilot does make a great back spot if you don't have the space though.

[NevilleLighting]

[QUOTE=jxgriffi;147962]This is not true. I've been an Autopilot tech and designer on many shows. You can enable it for any light for any transmitter and the "box" takes over pan, tilt, iris (if enabled), etc. When you don't need it, you turn the channel off and the fixture behaves like normal.

JX, thanks for the clarification. I was unsure on that one. How is response time these days? I've been curious about that.

[derekleffew]

...There was another company at LDI this past year. In the demo, moving lights were tracking a 2' diameter sphere suspended by three cables, and I believe the hoists were relaying via a computer position information to the fixtures. Anyone remember the company?

Thanks to gafftaper for taking a picture, but I still can't see the company name. May have been the Redirection en htm (Cyberhoist.com) booth.

...This was a cool product. The ball on the right moved around the booth in 3D space on three lines. It was lit by three movers, and a camera tracked it. The mover on that truss in the foreground was always moving at weird angles too. The whole thing was modeled in a computer allowing the movers and camera to track the moving ball perfectly.

As JChenault said, the purpose of the demonstration was "how precisely they could read the position of the winches - not how they could track a moving object." Still it might work if we could attach three wires to each performer. Appears to be an Ion in the picture, but the lighting console is secondary, as the automation computer does the number-crunching and sends out the proper pan/tilt data, re-merged with the incoming DMX.