This is topic Home built automation (for cinema). in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by William Phillips (Member # 1162) on 07-01-2002, 03:29 PM:
Dont Know if this is the right place for this topicso here we go
Has anyone out there built their own automation?.
I`m asking this as i want to build a very basic automation controller for the house and screen lights. House full-half-off etc
I know that there are lots of good systems out there that do what I want but building stuff is fun 
.My house and screen light controller works well that i built as does the auto strike unit I built for another cinema.
If anyone has would they be willing to part with a circuit diagram??
Posted by Paul G. Thompson (Member # 655) on 07-01-2002, 07:01 PM:
Indeed, building stuff is fun. However, using it in a commercial enviroment could be a problem due to fire codes, etc. Some countries are rougher than others about what you can use and what you cannot use. Since you are in the UK, their rules might be tougher than others. In the US, if it does not have a UL certification, legally we cannot install it. Most electrical inspectors will look for that UL certification. If that certification is not affixed to the equipment, he/she probably will not sign it off until a certification is presented.
Before you build something, I would recommend you find out what the rules are in your area.
Posted by Steve Kraus (Member # 476) on 07-01-2002, 07:20 PM:
I'm curious how UL, a private company, can issue certifications which then become the basis of law.
Posted by Paul G. Thompson (Member # 655) on 07-01-2002, 07:26 PM:
Steve, if you find the answer, please let me know. We had a Cutler-Hammer ice cube relay for slide projector switching installed by an electrician recently, and the electrical inspector refused to sign it off until the contractor provided a UL certification for that relay.
What a butthole!!!!!! 
At the radio station, our 5KW transmitter had a 3-phase surge suppressor that was supplied with the transmitter package. When we lost the radio station to a flood, we moved the transmitter to higher ground, and got back on the air. When we had a new transmitter facility permanently in place, we installed the surge protector. The electrical inspector would not sign it off until I produced a UL Certification.
Same Crap - Different shovel - Different day - Different month - Different year - Different butthole!
So it is not just the inspector - apparently, it is the law.
Posted by Dave Williams (Member # 299) on 07-02-2002, 01:23 AM:
I have had the same experience with inspectors demanding that all of our equipment be UL certified. For some reason these guys are like electrical gods. Surely even UL has made mistakes, right?Dave
Posted by Paul G. Thompson (Member # 655) on 07-02-2002, 02:20 AM:
Yeah, Dave. To top matters off, some of that stuff UL certifies is has to be a joke! I would not even trust some of it anymore than the green cheese on the moon.
Posted by Mark Hathaway (Member # 1044) on 07-02-2002, 02:40 AM:
Legal issues aside, do you need serial control, or simple relay closures to control everything you want to control?
Any old PC could easily do any automation.
Mark Hathaway
Atlab Image and Sound Technology
Melbourne, Australia
Posted by Paul G. Thompson (Member # 655) on 07-02-2002, 02:52 AM:
Mark, I respectfully disagree. Some of the controls for contact closures have as high as 25 amp surge draw. No standard store purchased computer will handle that without the use auxiliary relays. An industrial strength commercial computer that is capable of handling loads like that would normally be extremely expensive.If you are talking about pulse logic such as what DTS, Dolby, or others use, whether it be dimmers or what have you where there is no appreciable voltage present or no apprecialble current draw on contact closures, the switch cards available for the average run-of-the-mill computers will probably work just fine.
We use those cards for audio source switching via soft pulse logic in the broadcasting industry.
I use the term "soft pulse logic" (although it may be politically incorrect) to describe extremely low current and low voltage switching via some goofy IC flat pack.
Posted by Mark Hathaway (Member # 1044) on 07-02-2002, 03:01 AM:
No, but a simple opto isolated parrallel port control board will be able to drive an scr/triac for 25 amps.
25 amps?
who switches 25 amps in the bio? what happened to dimmers with automation wiring and automation wiring for curtains/masking?Mark Hathaway
Posted by Paul G. Thompson (Member # 655) on 07-02-2002, 03:07 AM:
Motor start draw. Some are as high as 25 amps until the starter switch dis-engages. Relays or contactors can handle that.
Yes, a computer of almost any sort will handle a SCR or Triac if the computer is equipped with the necessary hardware.....but you still need the SCR or Triac. If you have to build a box to put it in, you are back to square one unless you can get it certified. Furthermore, I don't think that a SCR or Triac will keep the projector motor happy. It'll probably go over like a lead balloon with a split phase, three-phase, or a single phase repulsion-induction motor. Some of the masking and curtains might work with it, but that depends on the manufacturer, the design, and what is used in its controller to make it work, along with how it is configured.Why fart with it? It still might not pass certification, unless it was a total "plug-in" package that had the whole shebang approved. I am sure you can build something that will work along with many of us. But, if it is not certified, forget it. It will probably be rejected, even though your device may be better and more reliable than some of the crap that is manufactured today. 
Sometimes I think it boils down to "who is in bed with whom" when the certifications are issued.
The final point is....The damned thing still has to be certified if it is going to be used in an industrial application. Without the certification, you might be held liable in event of a fire or some catastrophe that results in a loss of life or injury.
Posted by Oscar Neundorfer (Member # 458) on 07-02-2002, 07:14 AM:
Steve,UL standards are based in good measure on the National Electrical Code (NEC) which IS the law in most locations (although I am not certain if all jurisdictions consider it the law). UL tests electrical and electronic equipment to see if it meets certain minimum safety requirements regarding fire and shock hazards. By the way, there are other testing labs besides UL which are legally acceptable anywhere in the country. I have used UL and one other lab, ETL, for my testing needs. These are known as NRTL's (Nationally Recognized Testing Laboratory).
Many localities insist on UL or some other lab certification because they know these products have met NEC conditions as part of their testing.
The real problem to me is that so many electrical inspectors THINK they know what the NEC says. If you have ever looked at the NEC, it can be most confusing. I am a reasonably intelligent person, and I am confused by much of what I read in the NEC. So much of it seems so open to interpretation.
Posted by Steve Guttag (Member # 268) on 07-02-2002, 07:41 AM:
Relays and other non-purpose built items (that is, they don't know what they are going into when assembled) tend to carry a "UR" rating. Which is UL recognized.Steve
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"Old projectionists never die, they just changeover!"
Posted by Steve Kraus (Member # 476) on 07-02-2002, 07:43 AM:
I thought NEC covered wiring, wiring methods, and wiring devices, not the equipment itself.One thing I question about NEC is when the NEC is incorporated by reference as part of a given city or state's building code whether they can legally incorporate the ongoing, periodically updated NEC. In other words, I can see a governmental body adopting say, the 2000 NEC, and then when 2002 comes out adopting the new version as a separate legal act. But to simply adopt NEC as the law of the land on a blanket basis when this is a document which is then altered by a private organization would seem to me to be an illegal delegation of law making authority to a private party. I don't know if this is done or whether, as I have said, they adopt a particular version and then adopt the next one when it comes out. If the former then someone should challenge it because it certainly doesn't pass the smell test.
Posted by William Phillips (Member # 1162) on 07-02-2002, 12:44 PM:
All that i want to do is have some foil tape senosors that control the house lights and screen lights.
Manual starting of projector etc but have the option to control the ights manualy or automaticaly if we were needed to go and help downstairs or forgot the film was ending or something.
Normal routine here is to have house and screen at full before start 1min to go take the house lights down to 40% screen off as the advertising logo is hitting scren. At the tail advertising logo the screen lights come back on to 30% to colour wash the screen as the snipes etc are playing then off as the first trailers cert card is on screen. House lights go down to 30% while snipes are playing. At the end of the last trailer the screen lights go back on to 30% whilst courtisy snipes and digital logos are playing, both sets of lights go off whilst the films certification logo is on screen and stay off unitl the credits start then both upto 30% so as the customers can see to get out safely.
The dimmer control that i built is powered from the dimmers and is a minus 15volt supply (theatre dimmers) In my box i drop it down to
-10v . The control is done by pulsing either one of the 8 preset lines to 0v . I have got bulk standard SPST push switches . There is no nasty 240volts in my box ( only owing to the fact that i could get all the power needed from the dimmers) just good old fashoned low voltage at tiny amounts of current ( measured at 30ma max) . I know that a computer could do the job very well and interfacing it would be easy but I know nothing about writing programes for the things. I like transistors and chips, and had my way and enough space I would have valves for everything.
Posted by Ben Wales (Member # 92) on 07-02-2002, 02:19 PM:
What about a used Cinemation Mk2 unit?, like the one that Bernard buit at the Regal Cinema (Cranleigh).They are fairly simple to install and I belive you still can by the diode pins in France, I expect you could find a cheap one in the UK.
Posted by Mark Gulbrandsen (Member # 72) on 07-02-2002, 06:04 PM:
I've been really lucky with inspections considering the number of booths I've installed. Only one booth was rejected and it was the inspectors first day on the job in that case. Can't remember what he rejected though, nothing important or hard to deal with though. Seems like most inspectors don't know UL from homemade, or from anything else. Many only ever deal with one theatre in one town in their entire lives and do you think they have a clue as to what to look for......no way. As long as things are covered properly, and proper size breakers are on the proper size wire things have always passed for me. In Janesville, WI., a nortious inspection town, I wired up one booth of 7 and had the inspector over for a look see. He was pleased with it all, gave his blessings and we continued to wire the rest of them.
Mark @ GTS
Posted by Gordon McLeod (Member # 33) on 07-02-2002, 07:48 PM:
Several of the newer automations are all opto coupler outputs to things like dimmers and processors and using SSR blocks for power devices like the motor