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Rolling Your Own Wireless Communications System?
nuggetman asks: "My high school, like most others, has a theater program. One critical element of the show is the tech crew - the group of people behind the scenes who keep it all running. Communication between the stage manager (myself) and crew members (as well as between crew members) is critical. For this job right now, we're using standard hand-held walkie-talkies. They get the job done, but they're susceptible to dead batteries, incompatibility between VOX headsets, and interference from janitors, the office, hall monitors, and even the local McDonald's. We've been wanting to invest in a theater-communication system, but they can run extremely expensive. Is there any hardware out there that could use a standard PC (Linux or Windows) and some wireless headsets to roll your own communication system that could cover a long enough range (say the theater which is the size of a gym plus a decent range outside it) at a low enough cost? Our school just installed 802.11b/g throughout the hallways, so we could tap into that if necessary and add our own router near the stage if we had to."
1) Set up a private Counter Strike Server somewhere on the school LAN.
2) Get a laptop (with an 802.11g card in it, of course) and backpack for each crewmember.
3) Every crew member joins the game on their laptop, sets the laptop to never suspend, throws it in their backpack, and uses headsets to communicate with their team members!
Other than the sound of an explosion every three minutes or so, and the occasional "Terrorists Win!" all your communications problems are solved!
libertarianswag.com
Use yelling. Everyone comes equiped with all the right hardware. No sweat.
... which was admittedly about 18 years ago, we were happy to have the very latest technology... microphones and headphones (well, it was on a school-sized budget :-)
To be honest, I'd be surprised if WiFi would help you very much - it'd have to be a VoIP network, which isn't an obvious use of WiFi (the range is too short - most people would simply shout!)
Bluetooth might be an option, but they're basically clever walkie-talkies. Buy some rechargeable batteries and carry them. Sometimes the "clever" solution is the low-tech one...
Simon.
Physicists get Hadrons!
Some of my friends and I make up the A/V crew at my school, and I came up with an ingenious solution yet to be implemented: a zipline. The A/V booth is about 20 feet higher than the stage and a good 75 feet away, and we decided that a zipline would be the best way to get down to the stage to tell somebody something important.
I guess if you need to tell somebody something who's level with you then you'd have to invest in some model rocket engines or something.
The Human Cow - bringing you scrumtrelescence since 1995
I'm sure there are probably a lot of problems with interference, but shouldn't it be possible to just get better walkie-talkies? Computers have their own problems too, and I'd imagine that any device you are using to communicate will have dead battery problems (unless you want to have 20 ft cords running all over the place).
Makes you wonder how in the hell Shakespear ever got by without a Slashdot subscription.
Sheesh. It's high school, dude.
"If you want to improve, be content to be thought foolish and stupid." - Epictetus
And you can build a great communication system. It's easy to do, even my 5 year old nephew can do it.
Sorry, wrong company. I meant Vocera.
http://www.vocera.com
Sounds like a battery-management issue more than something requiring a complex software solution.
Linux: Free if your time is worthless.
Just buy a few ClearCom headsets. If wireless costs too much for you, get the old-style models and some lengths of XLR cable. Why waste time with all this computer stuff? It just complicates things. Use the simplest solution.
Why not buy some new handheld walki-talkies that have built in encryption (digital), wouldn't that be cheaper/easier than any computer network?
All you need is some tin cans and some stri-
Wait, does string count as "wireless?"
No, this is just silly. A laptop is going to be far more expensive than some high-quality two-way radios from Motorola or the like. Even if you already had the laptop, there's nothing that allows you to easily tap into VOIP via independent headsets. I'm not sure why regular, quality two-way radios (at $40 for a pair with rechargeable batteries) isn't good enough for this simple application?
Everyone is deriding the topic poster, but perhaps he's going to /. high school... It would be interesting to hear someone's cost effective solution for home brewed VOIP.
Part of the hardcore faithful who believed in Apple long before it was cool again to do so
While you could probably roll your own system with a lot of work, you are better off going with a real Clearcom system for theater use. They do both wired (cheaper, but it's really all you need for high school) and wireless (quite expensive). eBay often has some used eqipment you can buy as well. These systems are what are actually used in the field, and in many schools as well and are quite less likely to fail than a home-grown solution (rebooting the communications computer in the middle of a show so the SM can talk to a board-op is a very very bad idea). It may seem easier to put together a free system than buying the Real Thing, but by the time you purchase wireless eqipment and setup a custom system you have spent more in time and money than you would with a real system.
$800 for a CS-222 ClearCom 2 Channel Main Station is a lot of money, so another thing you may want to try are Motorola TalkAbout radios with headsets (not in VOX mode though, you don't want that in a theatre since you want to avoid unintentional chatter on the comms system). They tend to have fairly good range in my experience and if you take the time to pick out clear channels there isn't an issue with interference).
Use the money and buy more rechargeable batteries for the Walkie Talkies. Using batteries as an excuse to go VoIP, which also uses batteries, doesn't make sense.
If interference is the real issue, look into low frequency radios with a 5 watt range.
Sounds like someone wants a project.
More information for my original post.
Consider the cost of your solution vs the cost of a regular system.
CS-222 Clearcom 2 channel base station: $876
Belt pack: $238
Headset: $149
Now you'll need a headset for the base station (which is a station by its self). So say you need 1 stage left, 1 stage right, and your base station will be at FOH for sound/lighting. That takes a basic solution to $1799 without XLR cables. Buying used you could probably save even more. Remember, not every single person needs a headset. You basically need someone stage left, stage right and FOH to give messages and give cues. I was in highschool theator and I know how much everyone loves to wear the headset to sound important. I can also remember how many cues people missed because they were messing around on them.
Your best bet for cost and effectiveness is to get nicer walkie-talkies. At $40/pair Motorola FRS/GMRS radios have 22 channels, and a 2-mile range, plus you can get headset/microphones to go with em. I own a couple pairs and they're durable as hell (you shouldn't drop them in a lake, but mine came back to life anyway) and have 12+ continuous hrs on a couple AAs. Plus now you can multichannel your crew - Ch 1 is Lights/sound Ch 2 is backstage crew.... ~J >-- I'm not a pessimist, I'm a realist. It's not my fault that life sucks so much. --
-- I'm not a pessimist, I'm a realist. It's not my fault that life sucks so much. --
I work with a lot of presentations and lectures and I'm dying to know if there is any consumer or prosumer level digital microphone systems out there? Everything that you can find both at cheap ass Radio Shack and even high end audio stores is varying degrees of wireless. 900Mhz or 2.4Ghz just like cordless phones. Some through the word "digital" around but are still susceptible to interference and static.
What I'm dreaming of is something that is purely digital, from the device the speaker wears all the way to the speaker. I envision something like a Bluetooth wireless microphone similar to the bluetooth headsets that some cellular phones use. This bluetooth microphone would relay to either a box in the speaker's pocket or inside the lecturn. This box would then use CAT-5 or 802.11 to transmit the stream as a WAV or MP3 so that it could be played on a SlimMP3 or Shuttle connected directly to the speaker system. In theory the speaker could roam freely and speak clearly and sound crystal clear.
Is there anythign like this? One place that I work for is about 100 feet from high power lines. The resulting RF interference renders even the most expensive $600-800 wireless microphone solutions worthless. Wired microphone even have a problem, even with grounding wires you still pick up pops clicks and hums over fifty feet.
So, how about it? There are plenty of devices that can take an audio stream off a network and output a sound wave? How about a device that can record the sound wave and output an audio stream?
FYI - consumer or prosumer means less than four digits...I'm sure studios and recording studios have plenty of expensive options available.
-JoeShmoe
.
-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
You're a high school kid with walkie-talkies that can be used in pranks on McDonalds customers, janitors, and hall monitors, and you want to get rid of them?
The U.S. education system must be going downhill fast.
For something this "critical", you need technology that won't fail, but will also work in the kind of vast distances you're talking about. I suggest tin cans and string. Of course, you'll have to make sure nobody in the audience brought scissors, but with all the hi-tech anit-terrorism stuff they throw in schools these days, surely nobody can get in with sharp objects.
Been there, both in HS and college. Is there a particular reason it has to be a wireless system? We used wired ClearCom systems at both. Sometimes the cord was anoying, but usually it was not a problem, and it eliminates the VOX, noise, dead spots, etc. problems. A quick search found thisc h has some packages by Production Intercom that arn't too bad price wise, and you can probably find used equipment out there for less (eBay had some real ClearCom gear last time I looked)
http://springtree.net/pi/econocom.html
whi
The problems you cite are universal for portable communications systems. Batteries going dead, bad headsets etc. The key is planning and maintenance. If it is critical to the show then make darn sure the batteries are charged before the show starts and if one doesn't last the entire show then dispose of it. (Nicads and nickel-metal hydride need to be disposed of properly, Radio Shack does this for free) Keep a couple of spare radios ready to go and charge some extra batteries as well.
The better route to go is to get a license for your own radio channel and use higher end radios like police and firemen do. Schools often have a business band license for buses or maintenance that you could use on the off hours, this keeps other people off your frequency. The radios cost more but you are paying for reliability.
Don't whine that you don't have the money, get a system designed by your local radio (Motorola) dealer and then start getting the money through grants and donations. I get solicited all the time for free stuff and sometimes the dealers can hook you up with a corporation that is changing systems out and looking for a place to donate the old (but good) equipment too.
The main thing is plan ahead, and plan for things not going perfectly.
You can use FRS frequencies with FCC-approved FRS walkie talkies.
/not/ license free.
To use any GMRS-exclusive frequencies, you MUST purchase a license from the FCC and use the appropriate call sign and operating procedures.
GMRS radios are
Jim
I'll bet there is more than one large church in your town, and each one has wireless gear that they use for services sunday morning, and no other time. Just talk to them in advance and borrow their gear. Most would be more than willing if you ask correctly. (and take care of the equipment)
Note that there is an art to asking. Best is to have someone in the production (actor, teacher, think outside of tech crew) ask. I'm not sure about much else because as a tech guy I don't know how to ask.
Basically, it mimics a standard phone line, and any telephone device you plug in can communicate with the others. You can run long cables and use splitters [nearly] to your heart's content. For about $30-$50 per station (hundreds less than a real, however superior, Clear-Com system), you can purchase corded or cordless headset telephones which work nearly as well.
If you do that, be sure to get phones with mute capability; and if you go cordless, be sure to check on battery life and try to get phones that don't beep too loudly. You might even need to disassemble the cordless phone and disable the internal beeper to make it silent.
Two things that are really nice about true Clear-Com systems is that (1) they can be operated silently (i.e., without beeping), and (2) their mute/talk controls can be operated by feel alone -- you don't need to look at a mute LED to determine whether or not you're muted. Those features are hard to come by on unmodified corded and cordless phones.
In general, a theater intercom system needs to be absolutely reliable, and should also be full-duplex (which walkie-talkies are not, but telephones are). I'd shy away from creating a custom wireless soultion with unproven technology -- it will take much more time to develop and won't be as reliable. If anything goes wrong during a show, or if reception isn't good enough, you've got big trouble.
Forget about Wifi PDAs. Since Wifi is an always-on data connection, it's inefficient with power. Battery life sucks and you can't get headsets for them. Most have headphone jacks but no microphone jacks.
Still, if you want to try it XTEN makes a SIP softphone for PocketPC. There's probably ones for Palm OS too.
You could have a GMRS repeater you are unaware of, it would significantly improve range. But I have never seen a Target or WalMart use GMRS at all, typically they have "industrial" radio licenses.
Don't buy anything. Work on sharing the football team's headsets. They probably have a bigger budget than your theatre department anyways. This should work out as long as you never have a performance during a game, which you should never do anyways!!
If they don't have one, perhaps its a good time to talk about splitting the cost of one.
I would have to say that your best option would be to invest in the system
Think about it
1) The computer crashes.
2) PortabilityWill you be able to use this everywhere? You probably aren't going to take computers with you if you travel for competitions, and if you do that takes up your setup time.
3) Lag, you need real time conferencing behind the stage and can't wait even for a second of lag time if something goes wrong.
4) InterferenceMost people in the audience probably have a cell phone which operates very close to the 802.11b standard of 2.4ghz. You would quite possibly lose signal in that event, and even if just for a momment, you would have to wait till it was over, reconnect the Wifi signal, and restart the voice program.
Wouldn't it suck if suddenly the system went down? You would have no time to troubleshoot. I was in my high school theatre team and we used a system from Telex. It was awesome. Didn't matter how much noise was around you cause you could hear the voices with no problem and no lag. Just flip on the power unit and plug in. Could even connect multiple units together for cases when you didn't want cables everywhere. We never had a single instance of failure. Do yourself a favor and buy a real system.
I actually really like the wired clear com. There are no batterys to buy, and no interfearance.
The audio quality is as good as anything out there, the system is full duplex, so you can talk over each other. It uses standard xlr cable, so if you have a house snake you can just run it along that.
Try to get a used system, the equipment lasts forever.
My only warning about clearcom is to make shure that you don't have any short's in you cables, they can bring down the whold system. Also be cautious running it along with electrical cables, they can induce hum.
We use clear com during all our major preformances. We back it up with gmrs, wihch is another option, think of gmrs as being super walike talkies, the big benifit of gmrs is that you are assigned your own channel by the fcc, and the range is a few miles.
The wired clear com is still the standard in the entertainment industry, gmrs is also popular for non preformance comunication, but almost evryone I know of uses wired clear com for preformance.
Get the most basic clear com unit you can find, and a few headsets, you can expand to more headsets when you need, they'll be available just about forever.
Well art is art isn't it, but then again water is water; and east is east; and west is west; and if you take cranberries
I'm assuming that you people in the USA dont have a band allocated to the FRS?
Here in Canada, we have something called (you guessed it) FRS. Stands for Family Radio Service. The handsets run for around 25-40 bux canadian. You can usually get them in a pair for 50 dollars. They put out a half watt on vhf(get about a mile of range), and operate in a band allocated ONLY to the frs. There are..14 channels?
Hm, some quick googling turns up the fact that you DO have frs down there. Other than intermod, there isnt really much interference on the band. If you are using normal walkie-talkies, try some FRS radios. If the channel you are on has interference..switch to one of the others.
Here is the bandplan from the fcc.
Here are the radios at Best buy.
It's easier to fight for one's principles than to live up to them.
First off, let me preface this by saying that i have worked building large-scale theater shows, and as a lighting designer for 7 years. I have worked on shows including the Lion King, Cher, Phanton of the Opera, Miss Saigon, Tim McGraw, the Pan American Games, as well as numerous regional and touring theater shows and outdoor festivals.
Quite literally the only thing these shows have in common is the need for clear, reliable crew communications. During setup/strike (installation/teardown), crews usually have portable radios (Motorola Walkie-talkies generally), so everyone can keep in touch without shouting or running around looking for each other. Essential for big shows, unnecessary but nice for small one. However, for all shows, only "Clearcom" communications are used.
Clearcom is a brand-name of wired "party-line" communications sets. It's used generically for other brand systems, like Telex, HME, etc. It's the same thing you see camera operators on TV shoots wearing. Everyone has a headset and beltpac, and can talk to one another on a common "channel". Everything is hard-wired, and everything works, all the time, every time. The systems is used for calling show cues, as well as any other necessary communication during showtime.
However, the "wired" issue becomes a problem for some people. While audio and lighting techs can often stay put (they sit behind a board), stagehand/stage managers have to be mobile, often on stage. Usually they need to be able to communicate in a high-noise environment, and it must work reliably.
The only way to do this is via a wireless clearcom system. Telex, HME, and Clearcom are the big three, and all of their systems are inter-operable. I personally like HME's RadioComm, but all systems have their own benefits. Simply put, these systems are expensive but necessary. For a school situation, you can probably get away with 2 wireless stations, and 4 wired. But you can't cheap out on this. You need great headsets, and equally good beltpacs to go with them. When you're midshow, and you can't hear your cue, you'll know why.
I hope this helps. I realize that you were looking for a cheap way around the problem, but there isn't one. You'll find that with 95% of things in theater, cheaping-out never works. You buy a crappy light, or sound equipment, or cleacom, and life sux but things go on. You cheap out on rigging or construction, and people die. It's as simple as that.
-Michael Roy
-Michael Roy Some people are like Slinkies. Not really useful, but you can't help smiling when you see one tumble down
My school always used Clear-com's. They're not incredibly cheap, but certainly better than a PC. You also don't need to go all out and get a real base station...the portable one does nicely. BenFranske is right that people need to be all over the place, but they don't always have to be connected. We had someone on each side of the stage, the people running the boards, and the stage manager all connected. The stations are wired together, but it shouldn't be hard to find someone to run the XLR for you, or you can just run it through your normal audio snake.
In my high school theatre we have a clear-com system that we use for general communication but there are times on our larger productions in which it simply will not do. To remedy this, a friend and I hacked together a system by which to patch our clear-com output into our assisted listening devices. After completing this, we could give our stage crew boxes which would allow them to hear anything that went on on headset. We have two wireless microphones (1 lav, 1 handheld) which we gave to important crew members and patched their output back into the clear-com system. This allowed them to have two-way wireless communication using our existing equipment. Aside from that, I have had mixed luck with FRS depending on the space (all used on small productions). Another idea, if you are wanting to have use computers for this solution would be to install terminals on the sides of the stage which would run a custom software solution that would display cue information upon receiving commands from the stage manager. (I almost built this last year.) Also, a simple IRC system would work as well if you wanted text-based messaging but other than that, I think that a dedicated communications system would do you good.
While I'm fairly sure that some variant or successor to 802.11* will be the norm for wireless phone handsets one day, I don't think now is a good time to solve that problem with it.
:v)
Soon there will be 802.11-enabled mobiles in common use and all those base stations will make an awesome ad hoc network, but until then I'd suggest PRS handsets and headsets with VOX to save power.
If anyone is interested, I've developed a concept for sharing browser caches over LANs to speed up the access of all members here.
Vik
The technical director at my college just switched us from a 15 year old clear com system starting to show its age to a set of Motorola talkabouts. All of us hate them and use the clear coms when he is not around since we prefer them for the headsets and the fact that we don't have to worry about batteries . Full duplex is also a great feature except when everyone is trying to shout each other down.
I work on my schools television station. Anything big like recording the school plays we usually do FRS radios. I've seen other setups use the unused 2-pairs of wire in the CAT5 network ports in the school as the local loop in a homebrew intercom system.
Use those Motorola radios that get like 1 mile range. They're like $50 for a pair plus $10 for some headsets to plug in. That's what most high school theaters use, cause they're cheap, work well and are simple to operate.
Get your school on a multiline phone plan with low minutes but unlimited push to talk...long distance walkie talkie that no one can look in on and you won't pick up anyone else's stuff...maybe you could do 4 phones for around $100 a month? That still might be too much, but with free or discounted equipment the initial cost shouldn't be too much, maybe around $600, with a monthly fee. Sprint, Verizon, and Nextel all offer unlimited PTT...(that is if phones would even work in your theatre)
Being a geek is a good thing. But it doesn't mean that you have to make things more complicated than they need to be.
You obviously need voice communication without (expensive) signalling. So analog voice will do just fine. Forget computer or networking based ideas, going there is only going to sidetrack you from your goal. Remember that this is about getting your theater group to communicate, not about playing with geek toys.
Someone here has already mentioned 49 MHz headsets. Radio Shack and Maxon are common brands and those should work great for you. But if you need something with a little less interference then......
FRS, or Family Radio Service is another option. The radios are fairly inexpensive and can be had for $30 each or so. They offer multiple channels and CTCSS tones (if you don't know what that means either RTFM or get back to me, it's worth your time to understand it). Those should give you the range you're looking for. You won't get interference from businesses there, that frequency band is for non-commercial use. And if you do find someone interfering then gather information and turn them in to the FCC and your interference problem is gone.
Beyond that you could go for commercial land mobile gear. It works like FRS but you have to license a channel. You do get a lot more power and range. The drawback is that the school will have to apply for a license and that takes time. You'll have to budget $300 on up for each radio with the accessories you'll want.
If it were me I would try FRS first, a trial run with a couple of borrowed radios.
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