I was reading today, that in Gernmany by Siemens and Fraunhofer, researchers managed to build a 500Mbits / second home link over 5 meters by using a white LED as transmitter... That makes me wonder, are those white LEDs and I think they are in fact blue with some phosphor, easier to switch?
It is something I could try.... What sort of detector is best for white LEDs??
Oh, I think I found the paper:
Cool :-)
I wondered about the persistence of the phosphor but it seems this is taken care of:
"The data rate was achieved by detecting the blue part of the optical spectrum and applying discrete multi-tone modulation."
That makes about as much sense as a spark-gap transmitter. The eye diagram is horrible.
John
On a sunny day (Wed, 20 Jan 2010 07:02:04 -0800) it happened John Larkin wrote in :
I dunno, I was sort of thinking I can do this better with my RGB LED strips, by modulating the blue.
I wonder if colored blue LED's plastic will filter the other light enough so it can be used as a receiver, also if LEDs are sensitive enough as detector.
Just finished (yes really, the FLASH is about full) an other version of my IO_PIC. This one has a build in thermostat, a clock, and 2 programmable timers to set for example day and night time temperature. The whole thing uses 1.5 mA when not driving some load. That means battery or even capacitor backup for power glitches is easy, the clock would keep running, other settings are saved in EEPROM. Amazing what you can get in a PIC16F690.
IO_PIC.
for example day and night time temperature.
If you like the 16F690, check out the PIC18F14K22 for almost the same price (within a few percent).
On a sunny day (Wed, 20 Jan 2010 11:12:07 -0500) it happened Spehro Pefhany wrote in :
IO_PIC.
for example day and night time temperature.
That certainly looks interesting, internal Vref, and 16 KB FLASH, no pages, hardware multiplier, why 16 banks or 256 bytes data memory? They say it is for speed :-) but that depends on how often you have to switch banks, as that adds an instruction for each bankswitch. Maybe those banks can be used as local vars in subroutines.... It can write to its own FLASH, nice, bootloader....
It will take me some time to dig through that datasheet.
detector.
IO_PIC.
for example day and night time temperature.
Two words: 'Access RAM'
Yeah, that's the downside of these complex chips.
detector.
IO_PIC.
for example day and night time temperature.
Bank switching went out of fashion about the time that flush toilets came in.
John
On a sunny day (Wed, 20 Jan 2010 09:37:42 -0800) it happened John Larkin wrote in :
I do not think so, possibly there are more banks in use in PICs then toilets.
On a sunny day (Wed, 20 Jan 2010 12:05:35 -0500) it happened Spehro Pefhany wrote in :
Oh well... I guess if you program it in C you would not notice perhaps. I am used to those banks now, so is the US population, oh wait, those are other banks, these banks seem more reliable.
Na, that is with everything, better good documentation then none.
On a sunny day (Wed, 20 Jan 2010 11:12:07 -0500) it happened Spehro Pefhany wrote in :
PS: I have ordered some. Available here locally. That is what is so great about PICs.
On a sunny day (Wed, 20 Jan 2010 15:04:12 -0800) it happened Robert Baer wrote in :
I can assure you the document is fine.
"Error in document, could not be repaired" (Fox reader).
Probably "old" vs "new." I have and use v5.05 of Adobe's Acrobat tools. I have NOT purchased a newer version, though. I also have v9 of the Reader. Some of the PDF files I've been downloading, recently, read just fine with the newer Adobe free reader program but provide just that message, including the "could not be repaired" error, when the v5 reader starts on it. Worse, v5 will often _destroy_ the file so that v9 can no longer read it.
Jon
..is there such a thing as INDISCREET multi-tone modulation, that is to say instead of fixed bands, fixed phases, time slots, fixed frequencies, the use of pseudo-random combinations?
..if it can be used, then why LOOK at it?
Um... he means something other than the human eye. Look up with google, "eye diagram" together with "communications" and "modem" and probably "trellis" or "trellis diagram" and maybe also "constellation diagram" to help narrow the results a bit.
Jon
Opens just fine with Acrobat v7.1.0 ...Jim Thompson
On a sunny day (Wed, 20 Jan 2010 15:08:38 -0800) it happened Robert Baer wrote in :
I think they just used QAM 16 or QAM 64.
The document is *not* fine. But it is perfectly readable.
John
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