WLAN card to generate pulsed RF?

Hello Dimiter,

I did that in the early 90's but not with Windows. It was DOS and fairly easy, could still be done with an executable. It would automatically pop up a DOS box. The only disadvantage to the user would be that they'd have to click that little "x" up there or type in exit.

AFAIR I got over 50bps out of it but the flyback transformer in the monitor was screaming so bad that I stopped. Don't know what an LCD could do though.

It was a direct write to video card memory. Probably not a cool thing to do these days.

You could actually have them use their cell phones (maybe). Call

1-800-UPDATEME or something like that.

--
Regards, Joerg

http://www.analogconsultants.com

Hi Joerg,

I agree, this is a significant advantage. Probably the way to go if you have to be waterproof - you will still be able to make 10 bpS easily, which at your

1 - 2 K is still adequate (vs. the 300 bpS of Kansas City). The only disadvantage I see is the necessity to write some modulation software for Windows (yuck).

Oh I am sure it can be done (it has been done by me and other people some 20 years ago, it should still be doable :-).

That being said, the previously quoted argumentation holds still valid, no hole for the mike with a photodiode. On the other hand, you can use anything to record the Kansas City stream in an MP3 file and distribute this without having to mess around with MS hoops etc. You can even use a $50 MP3 player, put ist earplug near the mike, and not need to carry a laptop, once you get rid of the hole in the case issue. That would solve also the problem about annoying other people, not the waterproof requirement, though.

Dimiter

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Joerg wrote:

Hi Joerg,

I agree, this is a significant advantage. Probably the way to go if you have to be waterproof - you will still be able to make 10 bpS easily, which at your

1 - 2 K is still adequate (vs. the 300 bpS of Kansas City). The main disadvantage I see is the necessity to write some modulation software for Windows (yuck).

Oh I am sure it can be done (it has been done by me and other people some 20 years ago, it should still be doable :-).

That being said, the previously quoted argumentation holds still valid, no hole for the mike with a photodiode. On the other hand, you can use anything to record the Kansas City stream in an MP3 file and distribute this without having to mess around with MS hoops etc. You can even use a $50 MP3 player, put ist earplug near the mike, and not need to carry a laptop, once you get rid of the hole in the case issue. That would solve also the problem about annoying other people, not the waterproof requirement, though.

Dimiter

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Joerg wrote:

Hi Joerg,

Probably less. You can forget blinking the cold cathode lamp - the invertor is probably too slow to drive in all cases. I guess assuming a 30 Hz refresh rate will be conservative enough, and with some more conservativism you go down to the 10 bpS, which I am sure can be doubled if you tweak all of the above and some more :-), but that will be about all, I guess.

Don't know about windows, can just assume they are doing it similarly as I do it in DPS. Writing directly to video memory will not work because the offscreen buffers are refreshed into it upon OS' decision. However, you can write to the off-screen buffer memory (and signal the modification), this will take you as far as the refresh rate goes (30 Hz right now in front of me :-). Wait a minute, you can also open a window without an offscreen buffer in DPS, it only must remain uncovered by others to allow you to write to it the old way... I would expect there is something equivalent in windows, too.

Dimiter

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Joerg wrote:

Not cool, but people still do it - write to absolute address 0x000B0000 (monochrome) or 0x0000B800 (color) in DOS applications.

Microsoft knew that it would be futile to tell programmers to stop, so on newer versions of Windows, the machine traps write attempts to video memory, sends notification to the portion of the operating system that controls DOS boxes and DOS video memory (CSRSS.EXE), at which point, whatever you were trying to do is done anyway, but in a non-intrusive manner, so the visual results are still the same.

Best,

-Le Chaud Lapin-

Hi Joerg,

I agree, this is a significant advantage. Probably the way to go if you have to be waterproof - you will still be able to make 10 bpS easily, which at your

1 - 2 K is still adequate (vs. the 300 bpS of Kansas City). The only disadvantage I see is the necessity to write some modulation software for Windows (yuck).

Oh I am sure it can be done (it has been done by me and other people some 20 years ago, it should still be doable :-).

That being said, the previously quoted argumentation holds still valid, no hole for the mike with a photodiode. On the other hand, you can use anything to record the Kansas City stream in an MP3 file and distribute this without having to mess around with MS hoops etc. You can even use a $50 MP3 player, put ist earplug near the mike, and not need to carry a laptop, once you get rid of the hole in the case issue. That would solve also the problem about annoying other people, not the waterproof requirement, though.

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

------------------------------------------------------

Joerg wrote:

Hi Joerg,

I agree, this is a significant advantage. Probably the way to go if you have to be waterproof - you will still be able to make 10 bpS easily, which at your

1 - 2 K is still adequate (vs. the 300 bpS of Kansas City). The only disadvantage I see is the necessity to write some modulation software for Windows (yuck).

Oh I am sure it can be done (it has been done by me and other people some 20 years ago, it should still be doable :-).

That being said, the previously quoted argumentation holds still valid, no hole for the mike with a photodiode. On the other hand, you can use anything to record the Kansas City stream in an MP3 file and distribute this without having to mess around with MS hoops etc. You can even use a $50 MP3 player, put ist earplug near the mike, and not need to carry a laptop, once you get rid of the hole in the case issue. That would solve also the problem about annoying other people, not the waterproof requirement, though.

Dimiter

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Joerg wrote:

Hi folks, sorry for the multiple posted message - I retried it a number of times, each time Google timed out and gave me a "server error, please do it again in 30 seconds" like message, the result being the flood originating here....

Aplologies to all,

Dimiter

I agree about simplicity. I think that there is a market for something like what you propose. Irda was probably the closest, but RF would be even better. Zigbee seemed promising until they followed the path of Bluetooth - loading to much poo into the specification. I downloaded the ZigBee specification once. It's huge.

There seems like there should be something in between, super simple as you say.

If you ever get to the point where you wannt to scratch this itch, I'd be inclined to do the software part. This space is not as well-cooked as some people think, IMO.

Best,

-Le Chaud Lapin-

All of which is gone in 64 bit versions of Windows.

In the header you are talking about using WLAN, which suggest that the

2.45 GHZ ISM (=Industrial, Scientific, Medical) band is used. You really can not know, if there is little or much noise on a particular site at a particular time, especially if a wide bandwidth receiver front end is used as the "simple AM receiver would" suggest.

Paul

Joerg wrote: [...]

[...] [...]

I think you probably could send at least a few dozen bits per second via the keyboard num-lock/caps-lock/scroll-lock LED's. I don't know what the API is like in Windows; under Linux, see man setleds and/or source of same. setleds works on virtual term's, not xterms. For xterms, see code at

-jiw

Hello Paul,

That would be no problem. If there is too much noise the "download ok" LED will not signal and the user needs to find a more quite spot. IOW away from stuff like microwave ovens or WLAN routers.

--
Regards, Joerg

http://www.analogconsultants.com

Hello Dimiter,

There is no easy access to the CCFL generator. But many LCD can probably be cycled at 30 Hz because that is the frame repetition rate of US television.

--
Regards, Joerg

http://www.analogconsultants.com

You mean the DOS box is gone, too? That would make any 64bit Windows version off limits in this office and lab. It would no longer be a useful OS.

--
Regards, Joerg

http://www.analogconsultants.com

Hello Dimiter,

That's a problem with most web "newsgroup interfaces". Most are unreliable. I had the same thing happen with the IEEE groups and also Yahoo groups. Plus numerous others. Ain't nothing like good old usenet via a good old newsreader :-)

--
Regards, Joerg

http://www.analogconsultants.com

Then there is the elitist club mentality with some of those standards. You have to be a (paying) member of the so-and-so alliance to be in the know. This keeps it out of mainstream. IOW if something isn't standard on any run-of-the-mills laptop or PDA it just isn't useful enough here.

Yes!

Well, it seems like there is no RF port available on regular hardware that could be used. So maybe I have to design one. 13.56MHz or something robust, have to check the legal implications when using it for data transfers. With older laptops you always had enough space for PCMCIA cards. Newer ones often will only feature USB ports. That means anything custom will stick out and, therefore, be prone to breaking off.

I am looking into another wireless project where timing is absolutely crucial. Latency needs to be around a millisecond or less on that one. If WLAN doesn't perform it's going to be yet another full custom thing. Like usual :-(

--
Regards, Joerg

http://www.analogconsultants.com

Hello James,

Now that's an idea. Except that on some laptops (like the Dell here in the office) these LEDs are rather dim.

--
Regards, Joerg

http://www.analogconsultants.com

If you're going to design your own hardware, it may be simpler to make a standalone device, like a TV remote, with a IR led that can be pointed at the device to perform a software upgrade.

Of course, this is only cost effective if each single user has a fairly large number of devices that need to be programmed.