What is sending out the signals ?

Hi, I opened up the remote controls of my old alarm system ( those reed switch ones) hoping to find some IR LEDs. But I got this instead, no IR LEDs. Can anyone tell me which component is sending out the signals ? Thanks in advance.

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karnuvap8 years ago
I agree with lemonie. That loop of track around the LED is the copper track aerial. Your alarm is a radio activated one. Check the instructions - do they say that the remote needs a line of sight to the base or do they say that it can activate the alarm (or de-activate it) from anohter room or from outside?
It's not sending out an IR signal- it's sending out radio signals. The blue gizmo with the screw adjuster in the middle is either an adjustable inductor or capacitor (they always look similar to me on the outside) and is part of a tuned tank circuit which determines the frequency it's working on. The signals that make the alarm turn on and off are riding on a carrier frequency.
That's how it looks to me.
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fujiapple (author) 8 years ago
Erm this is all that is inside of the remote. The remote is to enable/disable the reed switch alarm. I thought most remote uses IR leds, but in this case it isn't, so i just want to know which component is sending out the signals ?
lemonie8 years ago
If this is it in it's entirety, there may be a radio antenna on the board (in the form of a copper-track? L
Jayefuu8 years ago
I agree with b4ilose. A link to a similar alarm might be useful. What makes you think it uses IR? You said it uses a reed switch, in which case I'd imagine that when this circuit moves away from the magnet on the other part of the door/window frame, the circuit is broken and the alarm sounds......
b4ilose8 years ago
I'm pretty sure that there isn't any thing on that that is giving off an IR signal, unless there is an underside, in which isn't shown, if so take a picture and ask the question again.