I see trouble. Lots of stuff to consider.

Wireless Design and Protocol Discussion

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Postby Thonord » Fri Sep 28, 2007 12:17 am

I would argue that we are making a RF remote control. As in TV, model airplane etc. Atach it to a suitable flashunit with a hotshoe connector, it will flash the flash. Attach it to a suitable model car with a hotshoe connector, it will flash a headlamp. Is there a guy somewhere collecting royaltys from every remote control made in the whole world?

Ppl who agree need normally not reply, those who disagree or have questions do.
Or - just ignore me.
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Postby sesh » Fri Sep 28, 2007 12:34 am

A quick search of the Google Patents site brings up a couple of things you guys might want to look at:

http://www.google.com/patents?id=NGh7AA ... cketWizard - Wireless communication activation system and method

http://www.google.com/patents?id=uP93AA ... cketWizard - Wireless communication module

And a whole bunch of camera + flash related patents, a lot of which are owned by Pentax and Minolta - http://www.google.com/patents?lr=&spell ... ch+Patents
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Postby BertIvon » Fri Sep 28, 2007 7:21 am

seaton wrote:So what happens, if for example we come up with our own novel way of remotely triggering a flash with our own protocols and design independant of existing patents? ...

... a patent has to be detailed in its description of the components of the IP it is protecting, so can't just be "remotely triggering a flash via wireless".

I'm not a patent attourney either but I've dealt with the discussions involving them for a while so I think I have fair understanding of how it works.

A patent allows a person or company to make a specific legal claim to knowing how to do something a certain way. They write it in a legal sort of way that very specifically defines exactly what they are "claiming" to be the first to figure out. If you do the same thing in the same way as one of the claims in their patent, they can (and probably will) sue.

Sometimes ideas are granted very broadly. It is possible that the patent office could grant a claim "To activate a camera flash illumination unit by means of the control of the modulation of radio waves." and could then go on to make various sub-claims to that "by means of FM modulation, by means of AM OOK modulation, my means of the transmission of a predetermined coded data signal, by means of....." and as long as what they specifically discribe for the specific purpose they're describing has not already been demonstrated or written about in detail elsewhere - they will probably be granted the patent.

But the patent office also tries to keep things pretty narrow. Your patent is suppose to allow any person who is "skilled in the art" (so in this case, getting a pro photographer and an electrical engeneer and an RF engeneer in the same room together) - they should be able to make your "patented" product work using only the terms in your patent. The idea is you have to "reduce it to practice" - either by making one that works and showing it off, or by describing it (and all its parts, software, schematics, physcial design, etc) in such incredible detail that anyone in the art can make one.

So long story short - if you create a protocol from the ground up, you'll probably be just fine unless you accidentally do something that someone else has already done.

Remember patents are only in force for 20 years - so chances are, someone has thought up a radio signal to trip a camera flash more than 20 years ago - that's only 1987. Garage door openers and studio flash have been around longer than that. I seriously doubt there is still a patent in force to simply activate a flash unit by radio - there are a few people making them now.

But, for example PocketWizard may have patented some idea like "we send the trigger signal 5 times and the trigger signal is a preset digital code, and the receiver only trips if it gets the correct code 3 times within a certain period" - who knows, maybe that's why their units are so reliable. That's just an example of what could be.

I really doubt anyone will get sued as long as some group doesn't start actually handing out the units. As long as it's a free open access shopping list with assembly instructions, I doubt there is anything anyone can do. I can read anyone's patent and go get the materials to make one like it myself. Maybe I'm guilty of infringing myself, but the guy publishing the information isn't guilty of anything - the patent office themselves publishes all the info in the patent and they're not doing anything wrong.

I think it would be good to run a PCB without any components or solder on it as noted here and sell those for cost - it's just an empty non-functioning board so you're not violating anything in that. Then people can go around the net and get all the parts themselves and solder it together. If you make the solder pads large enough (larger than normal) it should actually be really easy to hand solder. Make sure and get a solder mask (usually standard on PCB's) and with some practice it almost solders itself. Just don't get the components too small - stick to normal through the hole type TO-92 and DIP packages and it should be easy.

It also occured to me that most processor chips allow programming from the board once installed if wired right. It may be easy enough to cut a USB plug off of something and just hook 2 of those wires to some pins on the board and use some software to flash the processor with new software - I've always built stuff that's flashed at the factory but I'm sure someone here can explain how someone can flash a program on their own workbench.

Then you could build a system that physically hooks together in a certain way with a certain board that specifies a certain radio chip (which the user can buy themselves and use for "their own development" and thus skip the FCC stuff) - then people here can write the software and post the hex files up for the end users to download and flash onto their units. You could also sell the chips cheap that are pre-flashed (already programed) as long as the function of what you're doing doesn't step on any patents.
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Patents ...

Postby Rudeofus » Sat Sep 29, 2007 11:40 pm

For all those still pondering the technicalities of patent law: Here's a nice writeup of what applies to both Europe and the US. Also with links to FAQs answering issues like how long a patent holds and how infringement is defined and dealt with.

Second: I've gone through the patents provided by sesh and, more importantly, some of the patents referenced within them.

As far as I can tell, the pocket wizard patents mentioned by sesh won't hurt us directly, since they describe very specific implementations and mostly those which we are not going to pursue anyway. It appears they are more targeted against camera manufacturers putting pocket wizard replacements into their cameras.

However, there are a few patents we should be aware of before we start designing.

1. Patents applying to potential efforts with optical communication:
USPAT6404987 is a description of the Canon wireless E-TTL system: light pulses, which control the remote flash, trigger pulse, which fires the remote flash. In 58 claims they do not describe a slave controller which causes a manually preset slave to ignore the power and whatever control commands and just fire when it's assigned slave group is told to fire :-) 12 years to go

USPAT5640623 is a primitive description of an addressing scheme for light pulse based communication, 10 years to go. It basically says that once a slave has determined that it is not the intended audience, it quits listening to optical commands for a period of time.

USPAT6127940 describes a wireless flash trigger protocol via optical pulse trains, where channels are contructed through the intervals and/or the duration of the pulse train. I'm not totally sure whether triggering a flash after receiving a PPM coded signal also falls under this patent. If yes, Canon, Metz and Sigma must have licensed this patent (unlikely), if not, we're fine. 11 years to go.

2. Patents potentially interfering with RF approaches:
USPAT5359375 patents any RF wireless link in which the receivers are attached to at least one photographic device (this could very well mean a flash). The RF wireless link is controlled by micro processors on each side. Note, that the unsuspecting name "Lab Partners Associates, Inc." turns out to be the company making pocket wizards, so that's a patent we need to pay very close attention to. It's been filed in 1992, so it's valid for another 5 years. This patent may be the main reason why pocket wizard has no competition on US soil except for companies operating from outside, thereby effectively bypassing patent rules.

No idea how the Elinchrome remote controller got by this patent, but maybe they licensed it. Or they don't have a micro controller on at least one side: don't laugh, but if we can make the receiver use an FPGA (of course without micro processor logic programmed into it) to just discern the various control signals we send, we may have a way to go ... someone should seriously check into this!
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Postby Elv000 » Thu Oct 04, 2007 2:14 pm

Can those in the know just clarify..... if where just publishing the plans to build this device is that still an infringement? (assuming it is already coverd by an exisiting patent in some form).
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Re: I see trouble. Lots of stuff to consider.

Postby chrisb » Thu Nov 01, 2007 1:27 am

Rudeofus wrote:
chrisb wrote:European union is the same as the FCC with regard to pre-certified radio devices.

AFAIK in Europe you are responsible for only selling equipment which follows the rules, but you are not required to go through official testing. Going through official testing might give you some slack if someone else proves your device to violate the rules (because you can claim you did everything you could), but it's not required.

No, In Europe if you are selling equipment, you are responsible for making sure it passes the requirements - which means going through official testing. There is no such thing as 'getting slack' if your equipment violates the rules. You violate the rules, you get a hefty fine and the equipment is taken off the market. Testing is required - check the EMC directive.

Rudeofus wrote:
chrisb wrote:if your lab is charging you re-test fees because you replaced a resistor, then you are being ripped off and need to change labs now. I work in an EMC test lab, if we told clients that they need to re-test because they changed a resistor, we wouldn't be in business for long.

I assume you have to recertify your new design, but a reasonable lab will decide that a change of resistor limiting current through an LED won't change the RF properties, so they'll certify it without testing it again. Note, that a resistor might also be there to set the bias current of your output driver, and the RF characteristics would change a lot if you modified that. Simply changing your design without notifying anybody probably won't stick.

Yes but what would be that likely hood of that particular change? Most manufacturers that are testing wireless devices are using pre-approved wireless modules. There are very few passive component changes you can make that would affect the EMC footprint in this sort of situation. If it's a change to passives in a wireless module, it would be the manufacturer making the changes, he wouldn't be making a resistor change just to see what happens.
Interestingly enough though, the manufacturers of Pocket Wizards designed their own radio transmitter instead of using a pre-approved wireless module.
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Re: I see trouble. Lots of stuff to consider.

Postby seaton » Thu Nov 01, 2007 1:55 am

[quote="chrisb]Interestingly enough though, the manufacturers of Pocket Wizards designed their own radio transmitter instead of using a pre-approved wireless module.[/quote]

Has anyone had a bo-peek under the RF shield of a Pocket Wizard? would love to see some photos.

What Frequency do they run at?

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Re: I see trouble. Lots of stuff to consider.

Postby JonSenior » Fri Nov 02, 2007 1:07 am

seaton wrote:Has anyone had a bo-peek under the RF shield of a Pocket Wizard? would love to see some photos.

I have a feeling it's 868 (Or thereabouts) in the US and 433 in Europe. Not sure about the rest of the world. In the patent, they talk about the radio being in excessive of FCC regulations but permissible because of the incredibly short active time. This is how they get the enormous range.

If you're going to go for FCC certs and you can do it, there's no reason not to build your own RF side.
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