Theater Lighting

Ok, i am going to make a long story short. I am the techie for a local play/musical. More specifically, i am the lighting person. Well, funny thing is, since our school is being renovated, the lighting system was taken down and stored safely way. According to the director of the play, the lighting controller board was destroyed in the process and since lost...

Now it is my job to make a replacement. I am lost. I highly doubt i will get a budget, either. I (we) need as cheap of a solution as possible.

Since we no-longer have a stage in our high school, all the lights have been moved to the middle school where the play will be held. With any luck, the lighting beams (the things on the ceiling) will have a dmx receiver on it, but if not, i guess i am screwed.

I have been searching around the internet looking for schematics, and the ones that i have found made me decide not to make one... So, i guess i am up a creek without a paddle.


Wednesday (two days from now) i will be checking out the lighting status as to what equipment we have and do not have. I am assuming ~24 lights will be used.


So i guess i should ask a few questions...

How do the lighting systems work? What i mean is, first off, how much voltage do these lights take? I am assuming 120vac at quite a few watts, but it is very possible they are 220... Also, what do the plugs look like? Like, for the lights themselves? Sure, i bet they vary from manufacture to manufacture. What type of DMX receiver would i need? (assuming the setup doesn't already have the receivers)




What i was thinking was, if i can get a DMX setup going, i could make a Linux DMX controller (if only i can find a GOOD DMX dongle) I was thinking maybe this one? https://llg.cubic.org/dmx30/

or this one for overkill... https://llg.cubic.org/dmx4linux/avrdmx.html


but, as i said before, i will need a receiver... OR AN ALTERNATIVE!

I've been usinig the Open DMX USB from enttec for several years now. (Currently US$60). They provide drivers for it, and it hooks to all my DMX receivers.

For software I use the free LightsUp! (check sourceforge). It gives me scripting, scenes, mapping, and curves. Nothing fancy, so it's perfect for someone who only has an hour to train. (I'm fond of this package because I helped design it.) It runs on XP, and doesn't need a parallel or serial port.

It's open source, so if you want to add something you could. (Needs Visual Studio to compile.) Probably pretty hard to port to linux, since it uses MFC for its GUI.

Linux would be nice... $60 sounds like quite a bit. I don't even know if we will be using DMX...

On the other hand, USB would be nice, there for i wouldn't mind windoz, simply for the fact i could use it on my laptop (it only had usb ports. no serial or parallel). If we by some chance have a DMX system, i will probably get a hold of an Open DMX USB.

thanks

Sounds like a computer with DMX is the best way to go. I'd prefer a computer to our HUGE light board at my old high school. Had enough channels to pull your hair out. (Not that we didn't hang 300-some lights not counting front of house... )

If I remember correctly, Elliot Sound Productions web site has some info on lighting, try here:
**broken link removed**

Id $60 is too much, you can buy it without the box for $45. If that's still too much, they have schematics on the site.

I think $60 should be just fine. Tomorrow i will find out if we have a DMX setup. I hope we do... i really want to geek out with a computer...

Assuming that there is NO DMX setup, what other type of setup may it be? The more i think about it, it doesn't seem plausable that it wouldn't be DMX... There are quite a few lights on the ceiling...

But, again, assuming it isn't DMX, are there any other possibilities?

If it's not DMX, then it might be AMX or MIDI. Hopefully not, as equipment is harder to get in the past decade or so.

If it's not DMX, then it might be AMX or MIDI. Hopefully not, as equipment is harder to get in the past decade or so.

Click to expand...

Let's hope...

If there is no DMX, what we used to do was hire a Dimmer (assuming you have 3phase near by), run power to the lights by extension leads and then feed the DMX from our lighting board into this hired dimmer. (Hire cost us about AU$30 a day)
This used to happen because our existing dimmer wouldn't handle the load for some shows, so this is what we did.

You could then use this USB DMX device to run the dimmer. There is also another "DIY" device called the "manolator" - **broken link removed**
This however is a parallel interface and you mentioned that you don't have parallel.
As it is PIC Based however, you could use a pic with USB and mod the firmware... I don't know if you'd want to bother with this though, I wouldn't....

No DMX. No anything.

It turns out that the middle school's stage can't pump out enough power to control the REAL stage lights, so i am stuck using some piece of crap some guy put together. The real stage lights will be installed AFTER our play.

Oh well... what can you do?

so, now i have to make a crappy little switch board with dimmers to control the home-made lights.

Time for some math...

I have 3 strips of 27 lights (so a total of 81 lights). Assuming each light bulb is 75watts, that means all three strips will consume 6075watts (120vac). Therefore, i will need ~50 amps. I checked the breaker box. There are only 20's in there... 50 amps means i will have to tap into THREE separate circuits.

Is my math right? If so, Three separate 20's won't be TOO bad, but we are also renting two large light trees... I am sure those are going to draw a crap load, too...

Perhaps 50watt bulbs, or even 25watt bulbs would be a better choice...

Marks256 said:

No DMX. No anything.

It turns out that the middle school's stage can't pump out enough power to control the REAL stage lights, so i am stuck using some piece of crap some guy put together. The real stage lights will be installed AFTER our play.

Oh well... what can you do?

so, now i have to make a crappy little switch board with dimmers to control the home-made lights.

Time for some math...

I have 3 strips of 27 lights (so a total of 81 lights). Assuming each light bulb is 75watts, that means all three strips will consume 6075watts (120vac). Therefore, i will need ~50 amps. I checked the breaker box. There are only 20's in there... 50 amps means i will have to tap into THREE separate circuits.

Is my math right? If so, Three separate 20's won't be TOO bad, but we are also renting two large light trees... I am sure those are going to draw a crap load, too...

Perhaps 50watt bulbs, or even 25watt bulbs would be a better choice...

Click to expand...

How big is your stage? Those lamps sound too low wattage to do anything. Best of luck with the new stage lights...after the production.

The stage isn't very big. I would say about 50 foot wide. Then again, i am not good at estimating distance...

Any bigger lights, and there would be no way i could control them, let alone power them... I have about 12 600watt dimmer switches, but i doubt they would be able to do much...

This isn't sounding too fun... I am deathly afraid of mains power for some reason...

I think what we need is a budget... And some nice big fat breakers...

Marks256 said:

I have 3 strips of 27 lights (so a total of 81 lights). Assuming each light bulb is 75watts, that means all three strips will consume 6075watts (120vac). Therefore, i will need ~50 amps. I checked the breaker box. There are only 20's in there... 50 amps means i will have to tap into THREE separate circuits.

Is my math right? If so, Three separate 20's won't be TOO bad, but we are also renting two large light trees... I am sure those are going to draw a crap load, too...

Perhaps 50watt bulbs, or even 25watt bulbs would be a better choice...

Click to expand...

This is what happens. The night of the event you're all set and running from taps in the breaker box. Then some event organizer plugs in a huge coffee maker.

Bob

Bob Scott said:

This is what happens. The night of the event you're all set and running from taps in the breaker box. Then some event organizer plugs in a huge coffee maker.

Bob

Click to expand...

Unfortunately i have seen that before...

Wanna know the sad part? The breaker box isn't even labeled! There is no telling what breaker goes where! You can tell that at one point in time it was labeled, but some idiot cut a hole in the door for easy access to the over head lights, and never replaced the tape! So now i am going to have to go through the breaker box, and trip breakers in order to find 3 or 4 separate circuits!


How many amps would be safe to pull from a 20 amp breaker? I am sure it isn't safe to pull THAT much (over heating?)

I have decided to only run 36 of the 52 lights. 100 watt bulbs. I have no idea how i am going to color them...

I would pull 15A continuous from a 20A breaker, but I feel safe pulling 20A for up to 5 minutes. Before doing so, I would make sure that my entire circuit uses 12 AWG wire, nothing smaller.

Breakers and legal wiring have plenty of safety factor.

How long do you have? Order up some gels, etc. if you can. Possibly some holders as well.

Depending on the production, you could probably narrow it down to two or three gels...try to get a warm and a cool at the very least. Subtle changes between the two will greatly enhance the show. Try some of the Rosco swatches on here:
**broken link removed**

Do all the lights need to be controlled independantly from each other?

Could you wire them phase-to-phase for 240V operation?

That would only be 25A.

You could connect two bulbs in series with each other or just replace them all with 240V bulbs.

Also watch out for the current rating of the cable, for 25A you need at least 4mm² (11AWG) and for 50A you need at least 10mm² (7AWG).

I would pull 15A continuous from a 20A breaker, but I feel safe pulling 20A for up to 5 minutes. Before doing so, I would make sure that my entire circuit uses 12 AWG wire, nothing smaller.

Breakers and legal wiring have plenty of safety factor.

Click to expand...

Ok. I narrowed it down to 36 bulbs instead of 81. They will be 100 watts, so i will be able to do it from 2 separate circuits @ ~15 amps each.

How long do you have? Order up some gels, etc. if you can. Possibly some holders as well.

Click to expand...

I would say no more than a month. That way i can work out any bugs in the system...

Do all the lights need to be controlled independantly from each other?

Could you wire them phase-to-phase for 240V operation?

That would only be 25A.

You could connect two bulbs in series with each other or just replace them all with 240V bulbs.

Also watch out for the current rating of the cable, for 25A you need at least 4mm² (11AWG) and for 50A you need at least 10mm² (7AWG).

Click to expand...

No, that would be out of the question. I was talking to the custodian so i could get a grip on power availability, and he didn't even know what the hell he was talking about, so i don't think i could gain access to 240 (actually, i don't even think there is a 240 line anyways. )

No, they do not have to be independent from each other. My plan is to have a left stage and a right stage. Each side will have 6 bulbs of each color (red yellow and blue). The six bulbs of each color will be all controlled together, as will the other side. SO, i will have a total of 6 dimmer switches (which will be maxed out wattage wise unless i can get some of the budget and get some 1000 watters)

Anyways, that brings me to a good question.

What size wire is good for 5 amps, also i need to know for 15 amps.


I have also decided that since i know nothing about large amounts of voltage, specifically the stuff i will be working with, i will have a certified electrician (family friend) look it over before it will be used. (yes, 120 isnt much, but again, for some reason i have a fear of it...)

Use 1mm² for 5A (18AWG) and 2mm² (14AWG) for 15A.

This is just a rough guide, it depends on the ventilation, ambient temperature, the temperature rise the insulation can stand, the type of copper and the acceptable voltage drop.

https://en.wikipedia.org/wiki/American_wire_gauge