Author Topic: Infrared heat sensor use.  (Read 870 times)

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Offline Hawaii00000Topic starter

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Infrared heat sensor use.
« on: May 20, 2010, 10:26:59 AM »
 Can any one help me with wiring the Directional Infrared Radial Sensor on this site: http://www.futurlec.com/PIR_Sensors.shtml
The spec sheet has the has 47k resistor a between the gnd and signal and an amplification circuit, are both these necessary for a microcontroller?

Heres the specs : http://www.futurlec.com/PIR_D203S.shtml
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Offline waltr

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Re: Infrared heat sensor use.
« Reply #1 on: May 20, 2010, 12:14:43 PM »
Yes. The resistor biases the internal FET and the output signal is very small therefore requires amplification.

Did you look at the PIR control chip on the Futurlec page? This might be the way to go as most of the required circuits are included, just external passive components are needed.

Offline Hawaii00000Topic starter

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Re: Infrared heat sensor use.
« Reply #2 on: May 20, 2010, 01:04:02 PM »
Yes. The resistor biases the internal FET and the output signal is very small therefore requires amplification.

Would a transistor work?

Did you look at the PIR control chip on the Futurlec page? This might be the way to go as most of the required circuits are included, just external passive components are needed.

Yeah, but that's not quite what I'm using the sensor for.

What about the 47k resistor between the gnd and signal? What is that for?
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Offline waltr

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Re: Infrared heat sensor use.
« Reply #3 on: May 20, 2010, 07:44:56 PM »
Quote
What about the 47k resistor between the gnd and signal? What is that for?

The resistor biases the internal FET. Look at the Equivalent Circuit on page two of the data sheet.

Depending on how large of a signal you need a transistor may work. You would need to experiment to find out.

Offline Hawaii00000Topic starter

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Re: Infrared heat sensor use.
« Reply #4 on: May 21, 2010, 08:15:22 AM »
Ok thanks for the replys!
"God chose to make the world according to very beautiful mathematics."
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