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Send and receive an electric signal...? Answered

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.


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",

returns some 'ibles that look promising, e.g.

  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.

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 ?

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

OK,I'll search for that but what does RF stand for,Radio Frequency/function/something else?

What do you mean forget it?Is it too tough for me or something else?

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.

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.

That;s alright and hey,congrats on being a Featured Author!


5 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.

That's a good idea.I will try to get one

YEAH,I got the word.Its wireless power transfer.I found some resourceful sites but please do make suggestions.

All you have to do is ask. Start with a battery, two wires, and a light bulb.

Just make a simple DC circuit.

Press a switch, and your relay will work.