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 Robotics / Handy Board / 1609
1608  |  1610
Subject: 
Re: IR Collision avoidance
Newsgroups: 
lugnet.robotics.handyboard
Date: 
Wed, 5 Mar 1997 04:33:22 GMT
Original-From: 
Adam <adam@ring.zenox.{Spamless}com>
Viewed: 
1923 times
  
Matt,

You mentioned an IR device from Digi-key.  Can you expand (part no.)
tel phone no. for Digi.  Process analog info from IRs to digital data
for HB?  What IRs are compatible and where might I get this stuff.

Your info into this would be greatly appreciated.  Thanks.

On Mon, 3 Mar 1997, Matt Harlan wrote:



Actually, I built the
portion of the transmitter that generates the 38Khz carrier, using a
single 555, and on the same board built the 567 portion of the
circuit, and then connected the signal on pin 5 of the 567 to pin 4
on the 555 to gate the 555 on and off at 200Hz.  Since the 567 is
also generating the modulating frequency (a luxury you don't have on
a standard remote-control setup, since the transmitter and the
receiver are eletrically separate from each other), it doesn't even
matter if the frequency drifts, because the frequency the detector is
looking for will always match it.  Feeding the output of one of the
IR sensors to the input of the 567 (as shown on the spec sheet)
allows the 567 to lock perfectly onto the modulated IR carrier, and
produces a solid TTL-level output that can be fed to the Handy Board.


This is exactly the same scheme I use.  I'm using an IR module from
Digi-key that has a side view, and five IR LED's spread around the front of
the module at different angles.  I have quite a few outputs, thanks to a
little harware hacking, so I just turn on each LED individually and look
for a reflection.  The onto the next LED.  I can get a sweep from -60° to
60° this way.



     \          |          /
      \         |         /
       \        |        /
        \       |       /
         \      |      /
          \     |     /
           \    |    /
            \   |   /
             \ *** /
              * _ *
               |_|

Kinda like this.  *'s are LED'S. the square is the IR module

Works pretty damn good.  Adjust the LED current and you get a range from a
few inches to a few feet.  Increase the current through the side LED's and
get better peripheral "vision".

I said a couple weeks ago that I would post a schematic and PCB pattern for
my sensor, and I will.  Once my exams are over.  I now realize that my
configureation is not the best for everybody, that whole digital output
thing.  So, I'm working on a better way.  Maybe something using the SPI.
Might even wipe up some code too, but no promises.

happy reflecting

harlan



_______________________
Matthew J. Harlan
Cornell University
Electrical Engineering
mjh10@cornell.edu






Message is in Reply To:
  Re: IR Collision avoidance
 
Actually, I built the (...) This is exactly the same scheme I use. I'm using an IR module from Digi-key that has a side view, and five IR LED's spread around the front of the module at different angles. I have quite a few outputs, thanks to a little (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)

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