Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Could an MP3 player record PIR sensor output?

Status
Not open for further replies.
R

Resistanceisfutile

Member level 4
Joined
Aug 22, 2012
Messages
77
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,288
Activity points
2,008
good evening.
i have a motion activated battery light that uses a PIR (passive infrared red) sensor (sorry, can't find a part number for it).
i wanted to get the output of the sensor, but do not have the knowledge or the components available to amplify it.
i've heard these modulate an AC signal. would an mp3 player be capable of recording a meaningful signal if i linked the terminals of the sensor to the mic jack?
 

Probably no and in any case it wouldn't tell you anything useful. The output of PIR sensors is a very slowly changing voltage, well below hearing range. The frequency depends on the rate of movement of the IR source between interleaved 'zones' and probably never goes higher than about 10Hz.

Brian.
 

Hi,

The "modulation" used in the PIR sensors is usually fixed frequency. It may be use to divide the PIR signal from ambient light.

But the modulation brings me to an idea.
If you manage to find the demodulated PIR signal....and feed this signal to a VCO...then this can generate an audible signal -frequency depends on PIR signal - that can be stored with an MP3 recorder.
This is a lot of effort.

Maybe it's easier to use a cheap PC scope. They usually have a data logging function.

Klaus
 

I'm not aware of modulation used with standard motion detectors. As pointed out by betwixt, the sensor output is low frequency AC in the 0.1 to 10 Hz range. The signal is generated by the object moving through the sensor zones mapped on the dual element PIR.

Modulation by optical shutters is however used with some IR temperature sensors and gas detectors.

If you know about motion detectors using modulation, please give references.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top