Subject:
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Re: electronics question please help
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 23 Feb 1999 23:42:02 GMT
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Original-From:
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K.L.McKinnon <klmckin@magmacomIHATESPAM.com>
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Viewed:
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3287 times
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The modulation frequency of the IR diodes must match the sensor
(depending on exact part number, around 38 KHz) within +/- 3 KHz. As
you move away from the center frequency, detection drops off sharply.
Are you able to confirm the modulation frequency?
One other problem that I ran into with this same circuit (built using a
PIC as the controller), was the LED itself was at a different wavelength
as the sensor. I did find that the RS superbright IR LED worked, but
some others did not. Alot of trial and error.
K.L. McKinnon
Bob Kelly wrote:
>
> Hello all,
>
> I hope there is a simple answer for this...
>
> I have attempted to build the circuit that will allow IR object detection
> using the Sharp IR detector module and a pair of "high output" infrared
> LEDs. The circuit I built was the one from "Mobile Robots - Inspiration to
> Completion, 2nd ed."
>
> The circuit calls for, among other things, a 74HC04 inverter. I obtained all
> the components from my local Radio Shack. The Inverter that I got is
> actually a 74HCT04 and the IR receiver was the same part number specified
> with the exception of a "B" suffix (hopefully to denote vertical mount Vs.
> horizontal mount). I implemented a slightly modified version of code to read
> the sensor that was based heavily on the info given in the book (I timed the
> LED pulse as required).
>
> Obviously, or I wouldn't be asking questions, the thing doesn't work. The
> LEDs are working (saw 'em through the video camera) and there is power to
> the Detector (yes, I grounded the case). I wired everything painstakingly
> per the diagram but I was wondering if it is necessary to supply steady
> voltage to the inverter (I have not, and the book didn't tell me to.) I did
> ground the inverter however.
>
> Is the supply of voltage to the 74HCT04 assumed in the diagram or is it
> likely I left something else out? Also, specific pin assignments for
> connection to the inverter were not given so I carefully wired them
> according to the pin out detail on the inverter package pin assignments and
> symbology. Is the 74HCT04 not interchangeable with the 74HC04?
>
> Are there any other things I should be aware of if trying to implement this
> circuit on a Handy Board?
>
> I am new at electronics and I thought this might be a nice "get my feet wet"
> starter project. I don't have access to fancy testing equipment so any help
> at all would be greatly appreciated. I apologize if this question is a
> little on the basic side.
>
> Thanks again,
>
> Bob K.
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Message is in Reply To:
 | | electronics question please help
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| Hello all, I hope there is a simple answer for this... I have attempted to build the circuit that will allow IR object detection using the Sharp IR detector module and a pair of "high output" infrared LEDs. The circuit I built was the one from (...) (28 years ago, 22-Feb-99, to lugnet.robotics.handyboard)
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