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Thread: Wireless transition to scanners

  1. #1
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    Default Wireless transition to scanners

    We have audio, video,midi USB and etc. Why can't we have a wireless from controller to projector. X Y R G B - 5 channel. How hard can it be.?
    I hired an Italian guy to do my wires. Now they look like spaghetti!

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    I think the hard bit is making all the different interlock and other signal crap people use into wireless. If you have all that stuff on board the projector and only need to get xyrgb to the projector, I think you could use any USB-wifi interface that's fast enough work with external sound or video cards to run your USB dac. If you're on Pangolin, I'm sure the .net box could work with a wireless hub or router as discussed in other threads.

    -Matt

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    No i'm talking about differential +5 -5v(+10 -10v) and 5v RGB.
    I have no USB/SERIAL/VPN/TELNET to my projector. Just plain simple XYRGB
    Last edited by Dr Laser; 01-20-2008 at 18:24.
    I hired an Italian guy to do my wires. Now they look like spaghetti!

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    it actually wouldent be that hard... there are modules you can use for both analog and digital wireless signal transmission (most of them work around 433mhz or 916mhz among others)

    the analog ones are usually for audio so they would probably work fine up to around 20+~khz which should be ok... that would get you 2 channels... but you need 5... sooooo you would need 3 modules... (probably use that extra 6th channel as a TTL interlock channel... if it looses that channel... aka looses rf, the projector goes into safety)

    something like that would need to be built/tested/tweaked and i dont have the time or money to do that so i cant be much help beyond the theoretical and datasheets

    you should check out something like this

    http://www.linxtechnologies.com/Prod...opment-System/

    to see if it would even work through wireless... maybe just run your XY through the modules... if it does then all you have to do is make a board with 3 transmitters and 3 recievers... make sure to pick different channels for each set of transmitters and recievers obviously, keep your antennas at least 1/4 wavelength apart and then call it a day

  5. #5
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    Terry Michaels at Laser Artistry had a system for this. His used off the shelf telephone 8 bit mux-demux chips and a spread spectrum RF link, and that was in early 1999 or so. the telecom chips sample at 64 kilohertz and make up a 1.5 Mb per second T1 stream. So you need quite a bit of bandwidth to send it. Terry was/is a professional data communications engineer and lasers were his second company. He had some great test equipment thats needed to pull this off.

    let see, at 60 kilosamples per second, x2 to get the actual bandwidth x 8 bits x 5 channels plus some overhead, if you add in the audio, yep, just about between 200 khz and 500 kilohertz of bandwidth. Thats gonna need broad band, spread spectrum to legally transmit these days, and 500 khz bandwidth is not a off the shelf radio.

    If you use the telecom stuff, its NRZ encoded, so you only send the bit changes and thus use just a little more then half the raw bandwidth, so you just need to find a expensive T1 wireless modem, and I'm sure such things exist.

    The Linx modules low end limit of 50 hertz is gonna require going to a FM subcarrier to do it right, so Linx says 100 khz max, that means a 10 khz to 90 khz subcarrier , which puts you some place around 18-20 KPPS max scanner speed for a true DC coupled link.

    Far better to park the controller at the projector and just send the show control.
    and then you would only need 4 of the linx modules, not 6-10.

    Steve Roberts
    Steve Roberts
    Last edited by mixedgas; 01-24-2008 at 07:07.

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    Quote Originally Posted by mixedgas View Post
    Terry Michaels at Laser Artistry had a system for this. His used off the shelf telephone 8 bit mux-demux chips and a spread spectrum RF link, and that was in early 1999 or so. the telecom chips sample at 64 kilohertz and make up a 1.5 Mb per second T1 stream. So you need quite a bit of bandwidth to send it. Terry was/is a professional data communications engineer and lasers were his second company. He had some great test equipment thats needed to pull this off.

    let see, at 60 kilosamples per second, x2 to get the actual bandwidth x 8 bits x 5 channels plus some overhead, if you add in the audio, yep, just about between 200 khz and 500 kilohertz of bandwidth. Thats gonna need broad band, spread spectrum to legally transmit these days, and 500 khz bandwidth is not a off the shelf radio.

    If you use the telecom stuff, its NRZ encoded, so you only send the bit changes and thus use just a little more then half the raw bandwidth, so you just need to find a expensive T1 wireless modem, and I'm sure such things exist.

    The Linx modules low end limit of 50 hertz is gonna require going to a FM subcarrier to do it right, so Linx says 100 khz max, that means a 10 khz to 90 khz subcarrier , which puts you some place around 18-20 KPPS max scanner speed for a true DC coupled link.

    Far better to park the controller at the projector and just send the show control.
    and then you would only need 4 of the linx modules, not 6-10.

    Steve Roberts
    Steve Roberts
    you can get wireless T1 equipment but most of it is designed for microwave links and operate on licenced frequencies...

    i think if you use multiple of those 900mhz data modules and send the data digitally using ADCs at the controller end and DACs at the recieving end you could probably get away with it... but it would be a pretty complex system

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    Quote Originally Posted by flecom View Post
    you can get wireless T1 equipment but most of it is designed for microwave links and operate on licenced frequencies...

    i think if you use multiple of those 900mhz data modules and send the data digitally using ADCs at the controller end and DACs at the recieving end you could probably get away with it... but it would be a pretty complex system
    depends on how the modules handle IMD, (intermodulation distortion) and front end overload, ie how close can you have two of them together without interference, and what the bandwidth of the PLL loop in the module is . If you go digital you might as well go whole hog, and have checksums, backchannel, error correction, etc. One of the problems is with laser, you need a very reliable link, or bad things happen. PLASA specifically reccomends against DMX for lasers for this very reason, and 902-928 spectrum in the US is in this order, Military Radar (primary) Government high power data links (FAA radar, primary) Amateur radio up to 1.5 kW (secondary) And ISM (industrial scientific and medical) is the least defended against interference, ie those modules as ISM have no guarentee (legal or practical) of preventing somebody else from interfering. In the US, master shutter is still gonna go down a cable if the CDRH has its way (and I agree)


    BTW, its $299.00 US for two modules from digikey, so your looking at 1 grand plus to try.

    Steve N8VKD

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    Quote Originally Posted by mixedgas View Post
    depends on how the modules handle IMD, (intermodulation distortion) and front end overload, ie how close can you have two of them together without interference, and what the bandwidth of the PLL loop in the module is . If you go digital you might as well go whole hog, and have checksums, backchannel, error correction, etc. One of the problems is with laser, you need a very reliable link, or bad things happen. PLASA specifically reccomends against DMX for lasers for this very reason, and 902-928 spectrum in the US is in this order, Military Radar (primary) Government high power data links (FAA radar, primary) Amateur radio up to 1.5 kW (secondary) And ISM (industrial scientific and medical) is the least defended against interference, ie those modules as ISM have no guarentee (legal or practical) of preventing somebody else from interfering. In the US, master shutter is still gonna go down a cable if the CDRH has its way (and I agree)


    BTW, its $299.00 US for two modules from digikey, so your looking at 1 grand plus to try.

    Steve N8VKD
    hey nobody said it would be cheap

    and yes i know a few things about the 900mhz band

    have a repeater here in downtown miami (150w) on 927.6125 -25mhz PL100hz

    Frank KI4IJQ

  9. #9
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    [QUOTE=flecom;42058]hey nobody said it would be cheap

    and yes i know a few things about the 900mhz band

    have a repeater here in downtown miami (150w) on 927.6125 -25mhz PL100hz

    --------------------
    Maxima mea culpa.

    Finally another ham in the laser show biz/hobby, that makes about 5 total nationally!

    When they opened up the band, like in 1990ish something I had about a watt @ 922.250 a maxon hand held biz band chassis with a dead final driving a doubler module and mitsubishi brick from a ancient cell phone, a RS scanner for a rx, and no one to talk to. I end up doing these bands like 900 and 10 ghz where around here you have to build two rigs, one for you, and one for whomever you can convince/bribe to go contesting on a Sat at 8 Am.

    Steve :-)

  10. #10
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    You might check out this link:
    http://www.pangolin.com/LD2000/QM200...Over_1700_cues

    We have a number of people using these along with a wireless bridge.

    Best regards,

    William Benner

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