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Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day

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Matthias Koch <matthias.koch@hot.uni-hannover.de> writes:
> By the way, Ledcomm can sync to a bright spotlight, too ! It will be
> an one directional communication this way, but... you can transfer
> data to all nodes at once.

This is really neat.  The one thing disappointing about ledcomm is that
it runs at such low bit rates, like 30 bps according to the ChibiOS
page.  I had thought its mechanism was different and that it used the
LED as a photodiode, capable of very fast detection.  I still wonder if
there's a way to do that.  Photodiodes are normally reverse biased (I
had forgotten or didn't know that earlier) so you'd have to use two or
maybe three IO pins to handle both the forward and reverse modes:

  pin o----resistor---o(pin)o----led||resistor----o pin

with another resistor across the led, making a voltage divider with the
first resistor.  The first and third pins would be digital so you could
forward or reverse bias the led by toggling them.  The middle pin is an
analog input that would detect when the led is generating some current,
by measuring the voltage change.  I have no idea whether this would be
sensitive enough though.

I know Forrest Mims wrote a lot of old stuff about using leds as
photodetectors.  I'm not sure if it was similar to ledcomm, or worked
some other way.

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1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-17 14:53 -0700
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Mark Wills <markwills1970@gmail.com> - 2015-06-18 00:07 -0700
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-18 09:23 -0700
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Alexander Skobelev <al.skobelev@gmail.com> - 2015-06-19 17:48 +0300
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-19 10:46 -0700
      Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Alexander Skobelev <al.skobelev@gmail.com> - 2015-06-22 12:43 +0300
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-19 21:08 -0700
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-19 23:00 -0700
      Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-20 15:33 -0700
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Mark Wills <markwills1970@gmail.com> - 2015-06-20 21:35 -0700
          Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-20 21:57 -0700
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-21 00:50 -0700
          Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-21 10:39 -0700
            Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-22 00:13 -0700
              Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-22 12:47 -0700
            Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day stephen@mpeforth.com (Stephen Pelc) - 2015-06-22 10:46 +0000
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day stephen@mpeforth.com (Stephen Pelc) - 2015-06-21 14:37 +0000
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Howerd <howerdo@yahoo.co.uk> - 2015-06-20 15:20 -0700
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-21 19:37 -0700
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-22 00:21 -0700
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-23 12:10 +0200
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-23 06:09 -0700
      Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day foxaudioresearch@gmail.com - 2015-06-23 15:10 -0700
      Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-24 14:50 +0200
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-24 13:57 -0700
          Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-24 17:13 -0700
            Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-25 00:05 -0700
              Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-25 15:03 +0200
              Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-25 15:51 +0200
            Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-25 14:43 +0200
          Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-25 15:07 +0200
            Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-25 10:36 -0700
              Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-26 11:15 +0200
              Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-06-26 11:21 +0200
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-26 07:45 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-26 07:59 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-26 07:51 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-26 13:10 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-06-26 13:12 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-06-26 14:54 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-07-19 00:30 -0700
                Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Paul Rubin <no.email@nospam.invalid> - 2015-07-20 15:18 -0700
  Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Mark Wills <markwills1970@gmail.com> - 2015-07-21 01:02 -0700
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-07-21 10:02 -0700
      Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-07-23 09:11 -0700
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Howerd <howerdo@yahoo.co.uk> - 2015-07-23 15:03 -0700
        Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day Mark Wills <markwills1970@gmail.com> - 2015-07-24 01:13 -0700
          Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-08-04 06:56 -0700
    Re: 1000 Scouts to solder together MSP430 Forth systems - a Forth computer each end of July - and planned to connect them all as a 1000 Bit Display on the last day JUERGEN <epldfpga@aol.com> - 2015-07-23 09:15 -0700

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