Forums

WLAN card to generate pulsed RF?

Started by Joerg October 26, 2006
Hi Joerg,

> The advantage is that it doesn't need a hole, just a translucent section > in the enclosure.
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).
> The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough.
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 http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Didi, > > > > >>Either one needs cables. .... > > > > What about a mike? I am not sure they get as cheap as photodiodes, > > but some tiny speakers probably will be cheap enough. Then, you can > > just use Kansas City modulation [for those who do not have a memory > > what this was: 4 periods of 1200 Hz=0, 8 periods of 2400 Hz=1], > > modulate > > an S3 (or even its 24-bit or 23-bit address variations, I have > > implemented > > them both but many years ago and now don't remember their respective > > S-numbers....). That would take minimal resources, I have managed to > > do Kansas City using a 1 MHz 6809 and part of a 6840 timer 20 or > > so years ago. Error correction will be limited to checksum only with > > S-records, though, which may be an issue, you may have to use some > > tougher error checking depending on how dramatic a device failure after > > reflashing would be... Then again, I remember my above mentioned > > "modem" would not be confused by a phone line signal - voice or > > whatever - and would detect all interleaved data frames, very rarely > > rejecting some because of checksum error(s). > > > Audio can annoy others. Many times you have to update firmware in the > field without moving the device, by bringing the laptop or PDA there. > The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough. > > While the cost of a mike would be negligible thanks to cell phones and > all that it requires a hole in the target device. That would be a > serious concern for anything that needs to operate outdoors. > > > > The other suggested option - flashing a display window - may also be > > good enough, and bringing that down to a binary stream may be somewhat > > cheaper than with the mike (the latter would likely need an opamp > > and a comparator/schmitt trigger, whereas the photodiode might > > take no opamp). > > > > The advantage is that it doesn't need a hole, just a translucent section > in the enclosure. The photodiode can, for example, be placed where a > display is. > > -- > Regards, Joerg > > http://www.analogconsultants.com
Hello Dimiter,

> >>The advantage is that it doesn't need a hole, just a translucent section >>in the enclosure. > > 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). >
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.
> >>The 1200/2400 scheme might be simple enough but to cram that into 0.5k >>or less of bootloader space could be tough. > > > 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,
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,

> The advantage is that it doesn't need a hole, just a translucent section > in the enclosure.
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).
> The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough.
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 http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Didi, > > > > >>Either one needs cables. .... > > > > What about a mike? I am not sure they get as cheap as photodiodes, > > but some tiny speakers probably will be cheap enough. Then, you can > > just use Kansas City modulation [for those who do not have a memory > > what this was: 4 periods of 1200 Hz=0, 8 periods of 2400 Hz=1], > > modulate > > an S3 (or even its 24-bit or 23-bit address variations, I have > > implemented > > them both but many years ago and now don't remember their respective > > S-numbers....). That would take minimal resources, I have managed to > > do Kansas City using a 1 MHz 6809 and part of a 6840 timer 20 or > > so years ago. Error correction will be limited to checksum only with > > S-records, though, which may be an issue, you may have to use some > > tougher error checking depending on how dramatic a device failure after > > reflashing would be... Then again, I remember my above mentioned > > "modem" would not be confused by a phone line signal - voice or > > whatever - and would detect all interleaved data frames, very rarely > > rejecting some because of checksum error(s). > > > Audio can annoy others. Many times you have to update firmware in the > field without moving the device, by bringing the laptop or PDA there. > The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough. > > While the cost of a mike would be negligible thanks to cell phones and > all that it requires a hole in the target device. That would be a > serious concern for anything that needs to operate outdoors. > > > > The other suggested option - flashing a display window - may also be > > good enough, and bringing that down to a binary stream may be somewhat > > cheaper than with the mike (the latter would likely need an opamp > > and a comparator/schmitt trigger, whereas the photodiode might > > take no opamp). > > > > The advantage is that it doesn't need a hole, just a translucent section > in the enclosure. The photodiode can, for example, be placed where a > display is. > > -- > Regards, Joerg > > http://www.analogconsultants.com
Hi Joerg,

> The advantage is that it doesn't need a hole, just a translucent section > in the enclosure.
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).
> The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough.
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 http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Didi, > > > > >>Either one needs cables. .... > > > > What about a mike? I am not sure they get as cheap as photodiodes, > > but some tiny speakers probably will be cheap enough. Then, you can > > just use Kansas City modulation [for those who do not have a memory > > what this was: 4 periods of 1200 Hz=0, 8 periods of 2400 Hz=1], > > modulate > > an S3 (or even its 24-bit or 23-bit address variations, I have > > implemented > > them both but many years ago and now don't remember their respective > > S-numbers....). That would take minimal resources, I have managed to > > do Kansas City using a 1 MHz 6809 and part of a 6840 timer 20 or > > so years ago. Error correction will be limited to checksum only with > > S-records, though, which may be an issue, you may have to use some > > tougher error checking depending on how dramatic a device failure after > > reflashing would be... Then again, I remember my above mentioned > > "modem" would not be confused by a phone line signal - voice or > > whatever - and would detect all interleaved data frames, very rarely > > rejecting some because of checksum error(s). > > > Audio can annoy others. Many times you have to update firmware in the > field without moving the device, by bringing the laptop or PDA there. > The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough. > > While the cost of a mike would be negligible thanks to cell phones and > all that it requires a hole in the target device. That would be a > serious concern for anything that needs to operate outdoors. > > > > The other suggested option - flashing a display window - may also be > > good enough, and bringing that down to a binary stream may be somewhat > > cheaper than with the mike (the latter would likely need an opamp > > and a comparator/schmitt trigger, whereas the photodiode might > > take no opamp). > > > > The advantage is that it doesn't need a hole, just a translucent section > in the enclosure. The photodiode can, for example, be placed where a > display is. > > -- > Regards, Joerg > > http://www.analogconsultants.com
Hi Joerg,

> 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.
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.
> It was a direct write to video card memory. Probably not a cool thing to > do these days.
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 ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Dimiter, > > > > >>The advantage is that it doesn't need a hole, just a translucent section > >>in the enclosure. > > > > 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). > > > > 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. > > > > >>The 1200/2400 scheme might be simple enough but to cram that into 0.5k > >>or less of bootloader space could be tough. > > > > > > 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, > > > You could actually have them use their cell phones (maybe). Call > 1-800-UPDATEME or something like that. > > -- > Regards, Joerg > > http://www.analogconsultants.com
Joerg wrote:
> Hello Dimiter, > > The main disadvantage I see is the necessity to write some modulation > > software for Windows (yuck). > > > > 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.
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,

> The advantage is that it doesn't need a hole, just a translucent section > in the enclosure.
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).
> The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough.
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 http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Didi, > > > > >>Either one needs cables. .... > > > > What about a mike? I am not sure they get as cheap as photodiodes, > > but some tiny speakers probably will be cheap enough. Then, you can > > just use Kansas City modulation [for those who do not have a memory > > what this was: 4 periods of 1200 Hz=0, 8 periods of 2400 Hz=1], > > modulate > > an S3 (or even its 24-bit or 23-bit address variations, I have > > implemented > > them both but many years ago and now don't remember their respective > > S-numbers....). That would take minimal resources, I have managed to > > do Kansas City using a 1 MHz 6809 and part of a 6840 timer 20 or > > so years ago. Error correction will be limited to checksum only with > > S-records, though, which may be an issue, you may have to use some > > tougher error checking depending on how dramatic a device failure after > > reflashing would be... Then again, I remember my above mentioned > > "modem" would not be confused by a phone line signal - voice or > > whatever - and would detect all interleaved data frames, very rarely > > rejecting some because of checksum error(s). > > > Audio can annoy others. Many times you have to update firmware in the > field without moving the device, by bringing the laptop or PDA there. > The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough. > > While the cost of a mike would be negligible thanks to cell phones and > all that it requires a hole in the target device. That would be a > serious concern for anything that needs to operate outdoors. > > > > The other suggested option - flashing a display window - may also be > > good enough, and bringing that down to a binary stream may be somewhat > > cheaper than with the mike (the latter would likely need an opamp > > and a comparator/schmitt trigger, whereas the photodiode might > > take no opamp). > > > > The advantage is that it doesn't need a hole, just a translucent section > in the enclosure. The photodiode can, for example, be placed where a > display is. > > -- > Regards, Joerg > > http://www.analogconsultants.com
Hi Joerg,

> The advantage is that it doesn't need a hole, just a translucent section > in the enclosure.
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).
> The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough.
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 http://www.tgi-sci.com ------------------------------------------------------ Joerg wrote:
> Hello Didi, > > > > >>Either one needs cables. .... > > > > What about a mike? I am not sure they get as cheap as photodiodes, > > but some tiny speakers probably will be cheap enough. Then, you can > > just use Kansas City modulation [for those who do not have a memory > > what this was: 4 periods of 1200 Hz=0, 8 periods of 2400 Hz=1], > > modulate > > an S3 (or even its 24-bit or 23-bit address variations, I have > > implemented > > them both but many years ago and now don't remember their respective > > S-numbers....). That would take minimal resources, I have managed to > > do Kansas City using a 1 MHz 6809 and part of a 6840 timer 20 or > > so years ago. Error correction will be limited to checksum only with > > S-records, though, which may be an issue, you may have to use some > > tougher error checking depending on how dramatic a device failure after > > reflashing would be... Then again, I remember my above mentioned > > "modem" would not be confused by a phone line signal - voice or > > whatever - and would detect all interleaved data frames, very rarely > > rejecting some because of checksum error(s). > > > Audio can annoy others. Many times you have to update firmware in the > field without moving the device, by bringing the laptop or PDA there. > The 1200/2400 scheme might be simple enough but to cram that into 0.5k > or less of bootloader space could be tough. > > While the cost of a mike would be negligible thanks to cell phones and > all that it requires a hole in the target device. That would be a > serious concern for anything that needs to operate outdoors. > > > > The other suggested option - flashing a display window - may also be > > good enough, and bringing that down to a binary stream may be somewhat > > cheaper than with the mike (the latter would likely need an opamp > > and a comparator/schmitt trigger, whereas the photodiode might > > take no opamp). > > > > The advantage is that it doesn't need a hole, just a translucent section > in the enclosure. The photodiode can, for example, be placed where a > display is. > > -- > Regards, Joerg > > http://www.analogconsultants.com
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

Joerg wrote:
> Le Chaud Lapin wrote: > Bluetooth is indeed too complicated. Speed is not an issue as it can be > even slower than 2400bd. Much slower if needed. But simplicity is > paramount here, both with respect to hardware as well as code space for > the bootloader on the uC. > > Irda would have been nice but this seems to not really have caught on. > None of the laptops I have checked had it. And even there it would > remain to be seen how much mandatory overhead they have crammed into it > which would get in the way of simplicity. Irda may be water under the > bridge though. If too many laptops in the field don't have it then I > cannot use it.
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-