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Subject: Re: Need help designing a circuit
Date: Sat, 02 Nov 2002 22:40:55 GMT
NNTP-Posting-Date: Sat, 02 Nov 2002 17:40:55 EST
Organization: Road Runner
The first thing that comes to mind is perhaps a Decimal to BCD encoder.
Each detector would then give a different number for the output of the
chip. Another way might be an analog multiplexer. Actually, now that I
have had another moment to consider it, this might be best done with a
simple array of sensors connected with a series of resistors, all the
same value. Each sensor has one lead connected to a different resistor,
and all the other leads of the sensors are then connected to a common
point. This means you get a different voltage depending on which sensor
is on. Now you have a pot on the shaft of the turntable so that it's
position determines the resistance of the pot. Using a simple op-amp
circuit or voltage comparator, you have the motor move until the voltage
from the array equals that from the pot. In this manner, you can also
determine which direction to turn, based on the polarity of the two
signals being compared. It's actually quite similar to the way polar
rotors for C-Band satellite dishes work.
> Ok...I'm not very bright...I haven't embraced microcontrollers, and like to
> do things with good old fashioned components and IC's. Keeping this in mind,
> I need a circuit that senses the position of an object, then turns on a
> motor to power a turntable to turn toward the object. I have several P.I.R
> detectors that will be placed in the center of the turntable. So I need a
> circuit that will sense which PIR has detected the object, and then switches
> off once the turntable is has turned towards the direction of the sensing
> PIR.. It doesn't need to have any sort of accuracy, as long as the turntable
> stops close to the subject(within about +/- 20 or 30 degrees). The
> switching can be either electro mechanical, or use LED Emitter/ Detectors.
> Any ideas?.
> Thanks in advance.