Send and receive an electric signal...?

Hi everyone,I just wanted to know how I can send a small electric signal over a distance(not more than 10 meters)wirelessly and receive it at the other end to trigger a relay which in turn of course.. switch higher voltages and do something say...light a LED.I don't know much about frequencies,oscillators and FM/AM or anything.So please let me know how I can get an idea about these and most importantly accomplish what I just mentioned above.

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Buy a keyfob wireless remote and compatible receiver. Videos in the link below will show you how to make things work.

https://www.adafruit.com/products/1095
https://www.adafruit.com/products/1096
https://www.adafruit.com/products/1097
https://www.adafruit.com/products/1098
Adarsh_tronix (author)  mpilchfamily4 years ago
Yeah Vyger had given me that suggestion and this weekend I plan to visit a neighbouring car service garage and try to get one.Thanks anyway
I think the easiest way to do this would be to modify a wireless doorbell, since a wireless doorbell is going to be relatively cheap (circa 20 USD at the time of this writing) and it comes with a matched radio transmitter and receiver.

The tricky part is going to be building your modification to the receiver circuit.  Probably the easiest thing to do would be to connect to a logic level output on some IC in the receiver, if you can find/discover which pin on which IC does this.   Or another way would be to build a circuit of your own that detects the presence of the ding-dong sound signal on the speaker wires.

Seems like there must be at least one or two good 'ibles here describing someone doing exactly this.  A search, using the Instructables search box,  on the phrase "wireless doorbell",
https://www.instructables.com/tag/type-id/?sort=none&q=wireless+doorbell

returns some 'ibles that look promising, e.g.
https://www.instructables.com/id/Wireless-doorbell-Morse-Code-transmitter-and-print/
https://www.instructables.com/id/Using-a-wireless-doorbell-to-turn-on-a-small-DC-mo-1/
https://www.instructables.com/id/Hack-a-wireless-doorbell-into-a-wireless-alarm-swi/

  I have not looked at any of these in detail, but a cursory glance shows that these authors are doing things with wireless doorbells, similar to what you say you want to do.
Adarsh_tronix (author)  Jack A Lopez4 years ago
Thank you Jack A Lopez,You might not believe this but none of the shops in my city sells wireless doorbells.I have been looking for one for quite a few months as I needed it for another project.But I had to face it,no wireless doorbells in my city!There isn't any reliable online sources in India from where I can buy electricals or electronics unless in bulk.I have always wanted to build such a bell and this question itself is sort of a foundation stone.Anyway,thanks.
Is this the question you asked a couple of weeks ago ?
Adarsh_tronix (author)  steveastrouk4 years ago
No Steve,I'm afraid I haven't brought this subject down as a question before.Well,there have been talks about wireless door bells and such but I don't think it involved anything about the circuits behind wireless transmission and receiving.
Only we had the identical question a few weeks ago...
You buy an RF receiver/transmitter combination
Adarsh_tronix (author)  steveastrouk4 years ago
OK,I'll search for that but what does RF stand for,Radio Frequency/function/something else?
Now we understand you want power transmission, forget it
Adarsh_tronix (author)  steveastrouk4 years ago
What do you mean forget it?Is it too tough for me or something else?
Its not necessary.
Kiteman4 years ago
Sorry, I assumed that you would know what I was talking about - your profile says you're 16, and in the UK most children know how to make a simple DC circuit before they're 12.
Adarsh_tronix (author)  Kiteman4 years ago
Are you sure that you mean a wireless transmitter-receiver circuit when
you say"a simple DC circuit ".A simple DC circuit,as I know is the basics and it doesn't need much devices.Just a battery,couple of wires,bulb etc.
Sorry, I misread the question - mea culpa.
Adarsh_tronix (author)  Kiteman4 years ago
That;s alright and hey,congrats on being a Featured Author!
Thanks!
Vyger4 years ago
I have a wireless key fob that is the remote for the security locks on my car. I push the button to lock and the car locks and set the alarm. The other button unlocks. I am sure you have seen these before. Go with that and adapt it to what you need.
Adarsh_tronix (author)  Vyger4 years ago
That's a good idea.I will try to get one
Adarsh_tronix (author) 4 years ago
YEAH,I got the word.Its wireless power transfer.I found some resourceful sites but please do make suggestions.
You can do that by "inductive power transfer"
Adarsh_tronix (author)  steveastrouk4 years ago
yes,I came across that in wikipedia.Thanks!
kelseymh4 years ago
All you have to do is ask. Start with a battery, two wires, and a light bulb.
Kiteman4 years ago
Just make a simple DC circuit.

Press a switch, and your relay will work.