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Subject: 
IR (formally 6.8nF cap)
Newsgroups: 
lugnet.robotics.handyboard
Date: 
Thu, 13 Jul 2000 16:32:52 GMT
Original-From: 
John Hatton <john.hatton@uk.airsysatm.thomson-csf.^Spamless^com>
Viewed: 
1320 times
  
I have asked for confirmation as to which frequency (38 or 40 KHz) is
correct. As my current components should give me a frequency of 39KHz
(1/3.883KOhm*6.6nF) I should be able to use either with out to much
problem. I am thinking of using the output circuitry for the IR LED
driver in conjunction with my hacked IR sensors which are rated for
40KHz so that I don't need to add extra circuitry. I am thinking of
having the extra LEDs either chained in a serial or parallel
configuration with the intended output LED (or maybe just replace it,
however the LEDs for the sensors should realy be collimated for
accuracy) and mounted with the associated sensor. Using the correct
memory location I will turn the IR output on to produce the 39KHz
carrier signal which the sensors should be able to use for distance
measurement. Take the reading from the sensors (possibly multiplexing
the values or maybe just feeding them into the analogue inputs) then
turning the output off. Does this sound like a possible use ?.

Thanks in advance for any help.

John Hatton



Message has 1 Reply:
  Re: IR (formally 6.8nF cap)
 
there's not really a big diff in the performance of the ir sensors given 38 or 40 khz. so either is fine, +/- a few khz just doesn't really matter, you have to detune 10 khz or so for it to matter. there is an issue whereby there are two different (...) (24 years ago, 13-Jul-00, to lugnet.robotics.handyboard)

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