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Topic: Using Infrared-Sensor - help! (Read 559 times) previous topic - next topic

muzik

hi,

i really need some help with my current project. I want to spread some Infra-Red LED in a room on the walls and my device should be able to recognize whether it is pointed towards one of them.

So i went to a store and bought this one:
http://www.conrad.de/ce/de/product/171050/IR-Empfaenger-Modul-Vishay-TSOP-31233-Wellen-Laenge-950-nm
and here is the english datasheet-pdf: http://www.produktinfo.conrad.com/datenblaetter/150000-174999/171050-da-01-en-IR_Empfaenger_Modul_TSOP_1733.pdf

and some of these

http://www.conrad.de/ce/de/product/153641/IR-LumineszenzdiodeEmitter-im-Kunststoffgehaeuse-Osram-Components-LD-274-Gehaeuseart-5-mm-Wellen-Laenge-950-nm

But my problem is, that my device should be movable with batteries and not wired to the LEDs... but because that IR-Receiver recognizes only 33Khz-Signals i would need to find a way either to make my IR-LEDs flicker in that frequenz (which as i understand would require a second arduino or controldevice to every IR-LED) or take a receiver, that can recognize constant IR-light.

Also the recognition should be as far as possible... i mean it should be possible wherever you stand in a room (and the IR-emitter is somewhere on the wall) the device sould be able to recognize when it is pointed towards the emitter.

So after talking about receiver... are these IR-LED strong enough?
I just saw a friend who simply made a IR-Remote for is Camera with one simple IR-LEDs like these and it was recognized all over the room.

i thank you in advance!

(if someone has an idea it would be super cool if he posts it fast because the store is still oben some 3h from now ;) so i could go and get some of the right stuff)

AmbiLobe

I have tested some IR devices like yours. The 33khz LED pulses are important for long distances like 8 meters. The receiver unit has an amplifier that amplifies 33khz signals and that amplifier ignores IR radiation that is not flickering at 33khz.  The amplifier has a bandpass filter centered at 33khz.

If you use DC  without 33khz, then the range will be less than 1 meter.

Put a 555 timer on each LED on your walls so they all flicker at 33khz. It can have a small battery, 555 timer at 33khz, and one IR LED. Use ten batteries, ten LEDs, ten 555 timers, twenty resistors, ten capacitors, and place them on your walls at 10 locations.
I am going to get going.

muzik

#2
Jul 06, 2013, 10:30 pm Last Edit: Jul 06, 2013, 10:32 pm by muzik Reason: 1
Hey thanks alot,

i was reading like crazy last hours and also stumbled over the 555-timer.

Since i am not really from that field i yet dont know how to properly put that together to work.

so for what exactly do i need the resistors and capacitors or better do you have any circuit sketch for that?
I still didn't got exactly how to use that 555-timer. I saw in the sheet, that there has to be some control-voltage to set up the right flickerspeed, right? And therefore i do need the capacitor and a resistor, right?

Since i will buy here, i just post you the 555-timer, i probably would buy if it is the right one:
http://www.conrad.de/ce/de/product/177113/Linear-IC-ST-Microelectronics-NE555-Gehaeuseart-DIL-8-Ausfuehrung-Praezisions-Timer
And here is the sheet:
http://www.produktinfo.conrad.com/datenblaetter/175000-199999/177113-da-01-en-IC_NE_555_TIMER_DIP_8_STM.pdf

There are also circuit sketches... but i still don't get it completely.
Maybe someone can explain the circuit needed in short - that would be awesome!



Put a 555 timer on each LED on your walls so they all flicker at 33khz. It can have a small battery, 555 timer at 33khz, and one IR LED. Use ten batteries, ten LEDs, ten 555 timers, twenty resistors, ten capacitors, and place them on your walls at 10 locations.





AmbiLobe

The 555 timer has a powerful output that can drive one IR LED.

http://www.555-timer-circuits.com/

For flickering use 2 resistors and one capacitor

http://www.555-timer-circuits.com/operating-modes.html

One resistor sets on time for IR. The other resistor sets the off time for the IR rays.

Use this calculator to find R and C values for 33khz

http://www.555-timer-circuits.com/calculator.html
I am going to get going.

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