Subject:
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Re: IR concept
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 28 Mar 1997 22:22:10 GMT
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Original-From:
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Adam <adam@ring.zenox.#Spamless#com>
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Viewed:
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1467 times
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In addition....
Perhaps I could use the on board IR header to turn on the
4 IR diode array with each diode in series with a current
limit resistor and in parallel with the IR output header..??
(I think this has been suggested before.)
On Fri, 28 Mar 1997, Adam wrote:
>
> An alternate IR system....
>
> I've been scanning through some of the IR stuff to see if
> I can't pick out a good solid system for collision avoidance
> on a short range (approx. 6-10cm) scale, but everything seems
> like alot of trouble.
>
> Some guys at Humber (where I currently am studying Computer
> Engineering) have let me in on their methodology. It's pretty
> good (effective and simple).
>
> The basic concept envolves an IR diode and transistor with the
> transistor running through a darlington pair to increase sensitivity
> before picking up the signal via an analog hookup on the HB.
> You say: "What about noise?" Ahhhh....
>
> The magic is in the code. You see the IR diode is hooked up to
> a triggering device through a transistor (either an onboard digital
> output from HB OR and offboard ascillator ie. 555 timer)
>
> Onboard method:
> Take a reading from the IR transistor (call this noise)
> Now, turn of the IR diode and take another reading.
> Find the difference in the readings and you have a signal
> with ambient effects eliminated. This has been tested and
> prooven.
>
> Offboard method:
> Instead of feeding a signal to turn on the diode, use a 555
> set up to oscillate the diode and take the same signal to a
> digital input on the HB. When the signal (from 555) is low
> (diode OFF) read transistor for noise. When the signal is
> high (diode ON) read for IR emmission+noise. The difference
> in the readings will give you the real data.
>
> The darlington pair is simply 2 2N4124 and a few resistors.
> The key device is the sensor. Not sure of the part no. right
> now, but I'll look it up. The while system could be built for
> under $10. A good ranging system such as this would run about
> $35 dollars as sold by Infusion Systems.
>
> I'm curious to know what others have to say about this approach.
>
> Thanks.
>
> ----------------------------------------------------------
> Adam B. Cox check out my web page
> Computer Engineer http://www.zenox.com/~adam
> Zenox Communications Corp. vmail: 416-241-7000 (x224)
> ----------------------------------------------------------
>
>
>
>
>
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Message has 1 Reply: | | Sonar Transducer Multiplexor
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| In your BMP circuit diagram that you posted recently, why did you use an open collector to feed the base of the transistor? Would it work if you connected the digital signal directly to the base? ---...--- ericson mar Master of Engineering Candidate (...) (27 years ago, 29-Mar-97, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | IR concept
|
| An alternate IR system.... I've been scanning through some of the IR stuff to see if I can't pick out a good solid system for collision avoidance on a short range (approx. 6-10cm) scale, but everything seems like alot of trouble. Some guys at Humber (...) (27 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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