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RS232 Radio communication?

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GTS_DK

New Member
Hi

I am making a project where i am using radio communication.
I have an rs232 connection and want to build a radiotransmitter that can transmit my digital signal.

Will it work if I am building the transmitter as on the blockdiagram which is attached?


I am planning that the oscillater should generate a 8 mhz sine wave, which go to a switch, so if the switch is on, it should send the sine wave out to an amplifier and send the signal out to the antenna.

and do you have any ideas how I can build the reciever?

I hope you can help me.
 

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GTS_DK

New Member
Nigel Goodwin.

I think it depends on which country you live in. And i only have to transmit in the area of 5m^2
So i am not going to broadcast anything. I am only using it to my project where i am communication with a modeltrain from Märklin :)
 
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tcmtech

Banned
Most Helpful Member
Years ago I saw a setup a kid built for a science fair project. It used 4 walkie talkie circuit boards. Two were set up as transmitters and two were the recievers. Each pair ran at a different frequency so they would not interfere with each other.

It worked pretty well as I recall. The working range was over a mile I think.
He just used what was normaly the audio carrier to send the signals back and forth. the baud rate was limited due to the audio band width of a cheap walkie talkie being rather low. But It did work!
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Nigel Goodwin.

I think it depends on which country you live in. And i only have to transmit in the area of 5m^2
So i am not going to broadcast anything. I am only using it to my project where i am communication with a modeltrain from Märklin :)
8MHz even at low power can span continents, yes regulations do vary from country to country, but you did'nt fill your location in on your profile.

8MHz would also be a really poor choose for short range communication on a small model, requiring large coils.
 

GTS_DK

New Member
8MHz even at low power can span continents, yes regulations do vary from country to country, but you did'nt fill your location in on your profile.

8MHz would also be a really poor choose for short range communication on a small model, requiring large coils.
I am from Denmark, but maybe i should choose another frequency then.
 

microtexan

New Member
If you can ascertain the legality of this project, you might do a search for "Amateur Packet Radio". I believe you could make that work with low power radio modules.:)
 

Sceadwian

Banned
I'm certain there are radio guidlines in Denmark, it's your responsibility to look them up. Building an RF module from scratch is no easy task, that's why they have modules you can buy =) Whole lot simpler, no muss no fuss no legalities, and they're cheap enough that the only reason you'd build one is if you had an honest to goodness interest in RF design, which if you don't even know what the RF laws in your country are you probably aren't that kind of person =)
 
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ccurtis

Well-Known Member
Yes it will work as a matter of principle. It is called on-off keying (OOK) modulation.

For a receiver you need an antenna and diode detector followed by an amplifier, at a minimum, to get the signal level needed at the input to a UART at the receive end.

You should get an amateur radio license so you can legally experiment at frequencies provided for radio experiments.
 

Sceadwian

Banned
Yeah, at 8mhz for a 1/4 wavelength whip you'd only need an antenna about 30 feet long.
 
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