Wireless Laser Control - improving reliabilty / safety

The a couple of peopl on here who have amzingly , wonderfully made the wheel for us all and shown how laser projction can be done wirelessly on the cheap ! ( in theory under £150-£100 )

Yes for commercial projects this is a big no no for insurance and safety concerns but im hoping a few of you can chuck in ideas to me developing my own wireless kit with improved reliabilty , and therefore safety .

One of the biggest concerns i can see from what i have read is the 2.4ghz frequency , due to the amount of other kit sharing that frequency a priority should be getting OFF that frequency !

Im guessing changing the frequency should be matter of desoldering and replacing a chip in the wireless router and print server / usb extender. I would imagine changing the frequency of a wireless laptop could b harder , anyone ever opened a Wireless USB stick , do they look easy enough to chage chip ?

...im a looking for disscussion on the theory of this and also , more importantly what frequency we could be safely moved to ......

A) is there a bank of frequecies going spare we could be allowed to use
b) is there a frequency that can be used that will as part of its nature extend the range comfortably
c)where can frequency chips be purchased


Any thoughts Appreciated


PAUL

These wireless microwave technologies revolve around an antenna and a circuit built for the 2.4 or in your desired instance preferably 5 ghz bands I service laptops. many wireless routers incorporate the mini-pci and express cards used in laptops and were it not for firmware issues this routers could easily have these boards upgraded. You would not ever swap a crystal in these devices but the whole transciever board some do one band or the other or both AKA atheros technology. Try the magazine for electronics experimenters called "NUTS & VOLTS" or online magazine elektor.com A discovery I made may save you heartache many laptop mfg.s in particular HP have done some very nasty doctoring on the boot bios software of thier laptops and you can open the bottom of your laptop and as easily as changing ram can upgrade either one of these type of wifi cards you may have but as the laptop boots it will read the PID product identification code and will not allow the laptop to boot unless the card is one of the few that was approved to be used in thier laptop. They say this is for FCC requirements I say for planned obsolescence very very nasty, it piseed me off so bad I went in and downloaded the BIOS got an editor located the pid for the approved wifi cards and edited one to my own hi power cards. SCREW HP They sold me a 64 bit laptop which never had drivers released for running 64 bit windows for over 2 years after I bought it I did the same thing I stole acer UK drivers and inserted the pids from my laptops same hardware devices but which had different PID's and viola screw HP the bastards!!!!!!! Anyway there are no crystals to change just whole boards.

There may be some frequencies opening up in the USA and maybe other countries as TV moves from analog broadcasts to digital at a new higher bandwidth, well maybe still in the uhf band?

Ok theres a few "ham Radio " and CB radio forums going about i will sign up for a couple and ak if anyone has any opinion on good safe , frequencies to move to.

Further its a chicken / egg situation ......... i could spend weeks debating th correct fequency to move to only to find a chip for that frequency is not obtainable or very expensive .

It may be better to trace
A) what frequency boards are available
B) the pricing of those boards
C) the dimensions and suitability/ compatibility of the kit its to be swapped with

May be better working it thru that way ..anybody any thoughts on where a wide selection of frequency chips / boards / crystals may be browsed and purchased ?

PAUL

Paul

Try sending a PM to Andyf97 on this forum. He's done lots of wireless networking with the QM2000.Net cards.

The solution he uses is to use VERY powerful and robust transmitters that basically obliterate any interference on the frequency.

I haven't got access to my PC at the moment otherwise i'd send you the links to the gear. It's mega stuff, but it doesn't come cheap!

Cheers

Jem

his system costs about £2000 he said just for fb3 wireless

ouch
! I could get some major hardware for what is that about $4000 usd

when i get home from work and get on MSN ill show him this threadand get him to respond.

unless he sees it before that

I have seen some very nifty repeter type dac that are used in the oil pipeline industry they do analylis on pressure flow etc from some type sensor they are coolas each unit is designed to pass data on to the next transciever in the chain this might have some great usage in this type application

Quote:

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Originally Posted by frank_1257

I have seen some very nifty repeter type dac that are used in the oil pipeline industry they do analylis on pressure flow etc from some type sensor they are coolas each unit is designed to pass data on to the next transciever in the chain this might have some great usage in this type application

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RADIO CONTROL OF LASERS IS A BAD IDEA!

The FCC is no longer ran by engineers, hasnt since President Clinton. It is now ran by lawyers who are only interested in selling off chunks of spectrum
So you will find a deaf ear to your needs in DC. Its the same in any contry, because the IARU treaties specify what channels can be used for what, in each of the 3 IARU regions, entertainment and industrial control are not big fish in the scheme of things, so there are very few channels allocated to them. This only gets changed about every 10 years, so the regulatory guys are always well behind updating to match available technology.

here it goes, after many years of operating licensed wireless mikes, ham radio, and having a business band channel for my family

The oil pipelines have a industry allocated frequency band for that, with co-ordination, otherwise they run 902 mhz spread spectrum and pray somebody doesnt set up with the same serial number, which sets the spreading sequence. They also have to "eat" interference from military radar in that band. Their system can retry sending packets until they get a "ack" back for the receiver. they are also in no hurry, if it takes them 1 second to retomely change a valve and verify a valid command, its not that critical,


One, if your in the states, forget it, CDRH is NOT gonna let you run wireless for shutter control, and certainly NOT in Arizona (ask me how I know). I wouldnt anyways, too much risk unless your actively verifying a two way link every millisecond and have a watchdog on the RF. PLASA (the co ordinating authority for theatrical entertainment electronics specifically disallows radio links for pyro and laser, so your insurance has grounds not to cover you)

Two the only way to get a clean frequency with no chance of jam is to get a co-ordinated
business license from the FCC or the UK radio authority (changes it name once a week)
In the US, you verify legal status, file for the license and pay a co-ordination fee to a private company that co-oridnates for that industry. They take a look at the channel registry and see what has little traffic in your area of operation. Ie you have to define a 30-50 mile radius around a specific area with GPS coordinates and you oten need to supply them a HAAT map, ie height above average terrain plus antenna gains and predicted coverage pattern. NOTE I said little traffic, NOT zero traffic, because all of the national clear channel frequencies were allocated to utilities or sold to private industry long ago. So you might end up sharing with 5 to 500 other users within 100 miles, and most of them will be using high power voice or multicast from multiple transmit sites.
So you must have a secure antijam technology. toime domain diversity Spread spectrum comes close, but 2.4 ghz ISM (industrial scientific and medical) shares its band with microwave ovens and military radar and ham radio, in fact 2.4 ghz wireless, is required to tolerate interfernece, ie you have to take whatever splatter the 3 higher ranking services in that band put out.
Same for 5.6 ghz, 902-928 etc.


a Biz band license is gonna be 75$ a year plus 150-300$ for the inital co ordination fee.

A two way "itinerent" microwave license (basically what you need) is gonna be about 1500$
to set up, not counting the cost of the gear, and itinerant (meaning NOT fixed in one place)
channels are pretty much filled with users as FCC and other radio authorities around the world reassign spectrum to big companies with lobbyists and $$$$.

You WILL NOT be allowed to build your own gear, you must use "type approved" commercial gear that is FCC approved to ensure you do not accidently radiate on some other critical serivces (like fire, or aviation) frequency.

YOu have little or no enforcement if somebody illegally "camps out" on your allocated frequecy either. FCC doesnt spend any time on enforcement any more, unless its related to national security, big cellular company, aircraft or law enforcement channels getting jammed or used illegally. However, lets assume you get a shared channel assignment in the enertainment band (155 mhz, 455 mhz) with channel 3 TV (owned by big companiy) if channel 3 TV complains about your constant laser show carrier mucking up their remote broadcasts, you will get a letter of noncompliance from the FCC and a notice of apperant liability for a fine. You then have 30 days to prove you didnt goof up in writing, and it doesnt go to court, by accepting the terms of your license, you agree you can be fined for a whoopsis without due process.


As for the "freed up" TV spectrum, none of it has been allocated to land-mobile, remote control, or FRS-CB-GMRS type services. It was sold to AT&T and Sprint for extra cell sites, mobile wireless movies on demand, a wireless form of digital cable TV, a probably unworkable national dispatching system for fire, and law enforcement, and homeland security.Spectrum is now sold at auction in the US, against several international treaties and the communciations act of 1932.
we little guys get it taken away, not given to us like in the old days. The only cities getting additional mobile radio channels not sold as a block in auction from TV are LA, DC, and possibly chicago. LA has had 450 to 512 mhz TV allocated to it for years to aid in spectrum congestion. Homeland security got the rest, and much of that went to private contractors to "SELL" dispatching servies to local government. No I'm not kidding, if your big city doesnt have enough channels, they are now supposed to have a option of buying the service from a nationwide contractor at $$$$$$$ per year.



You cannot legally use ham radio or CB for remote control of anything other then other ham radio gear, model aircraft, model cars , model boats etc.....And the hams have about 25 narrow assigned channels for RC, all shared with long distance voice. Only model aircraft have assigned non shared clear channels, for obvious reasons.

So to the best of my knowledge, ther eis nO two way real time talkback RC allocated to anything other then the military, the railroads, utilities and industrial cranes, and aviation services.

God knows what service the FCC would assign you to. licensed and co-ordinated Wireless mic/broadcast support/entertainment channels in the US are pretty much filled up.

You asked, now you know.

Steve Roberts, ham license N8VKD , Business band kilo alfa fox 3177