159Views22Replies

Author Options:

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.

23 Replies

user
mpilchfamilyBest Answer (author)2013-03-17
user

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

Select as Best AnswerUndo Best Answer

user
Jack A Lopez (author)2013-03-17

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.

Select as Best AnswerUndo Best Answer

user

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.

Select as Best AnswerUndo Best Answer

user
steveastrouk (author)2013-03-17

Is this the question you asked a couple of weeks ago ?

Select as Best AnswerUndo Best Answer

user

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.

Select as Best AnswerUndo Best Answer

user

Only we had the identical question a few weeks ago...
You buy an RF receiver/transmitter combination

Select as Best AnswerUndo Best Answer

user

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

Select as Best AnswerUndo Best Answer

user

Now we understand you want power transmission, forget it

Select as Best AnswerUndo Best Answer

user

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

Select as Best AnswerUndo Best Answer

user
Kiteman (author)2013-03-17

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.

Select as Best AnswerUndo Best Answer

user
Adarsh_tronix (author)Kiteman2013-03-18

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.

Select as Best AnswerUndo Best Answer

user
Kiteman (author)Adarsh_tronix2013-03-18

Sorry, I misread the question - mea culpa.

Select as Best AnswerUndo Best Answer

user
Adarsh_tronix (author)Kiteman2013-03-18

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

Select as Best AnswerUndo Best Answer

user
Vyger (author)2013-03-17

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.

Select as Best AnswerUndo Best Answer

user
Adarsh_tronix (author)Vyger2013-03-18

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

Select as Best AnswerUndo Best Answer

user
Adarsh_tronix (author)2013-03-17

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

Select as Best AnswerUndo Best Answer

user

You can do that by "inductive power transfer"

Select as Best AnswerUndo Best Answer

user

yes,I came across that in wikipedia.Thanks!

Select as Best AnswerUndo Best Answer

user
kelseymh (author)2013-03-17

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

Select as Best AnswerUndo Best Answer

user
Kiteman (author)2013-03-17

Just make a simple DC circuit.

Press a switch, and your relay will work.

Select as Best AnswerUndo Best Answer