Hey guys i want help in designing a circuit to transfer square wave pulse fed on transmitting end through a frequency generator and get it on receiving end and check it on an oscilloscope.
range should be about 10m and transfer is only one way
other specifications are as follows:
Square wave signal output from npn transistor with internal 2.7kΩ pull up resistor, dc coupled to supply.
8-25V dc
12mA maximum current consumption
0-15KHz frequency range
i would also require source code along with schematic.....plz help

 

Check eBay for a simple 315 MHz transmitter / receiver pair. Usually about $5.

 

how to proceed after i got the modules...
i guess that the signal cannot be directly fed to the transmitter.....it might require modulation

 

The cute little devices take care of all that. Just feed the 0 or 5 volt signal. The receiver will receive, demodulates and output the high/low as you input to the transmitter module. Very, very easy. Sometimes you have to 'tune' the transmitter or receiver by pulling the coil apart slightly or pressing together. Just connect a small audio amp (lm 386) to the receiver with a speaker and feed a 400 hz signal to the transmitter. adjust coils as needed to tune if needed. Use the same technique to adjust antennas and maximize tranmission distance.

Then disconnect the lm386 or similar and use with your application. If you want to get even simpler and avoid the audio amp and speaker, use an LED flashing at 1 to 10 hz instead of the audio amp. Be sure to add an appropriate current limiting resistor (220 to 330 ohms for a red LED).

Looks like the little module pairs are only $1.50 from china (including shipping if you can wait 3 to 5 weeks).

 

Here is a similar thing, it might give you some ideas;
http://www.romanblack.com/RF/cheapRFmodules.htm

 

Here is a similar thing, it might give you some ideas;
http://www.romanblack.com/RF/cheapRFmodules.htm

it was really very helpful...thanx a lot....it served me gr8 knowledge on rf....

 

The cute little devices take care of all that. Just feed the 0 or 5 volt signal. The receiver will receive, demodulates and output the high/low as you input to the transmitter module. Very, very easy. Sometimes you have to 'tune' the transmitter or receiver by pulling the coil apart slightly or pressing together. Just connect a small audio amp (lm 386) to the receiver with a speaker and feed a 400 hz signal to the transmitter. adjust coils as needed to tune if needed. Use the same technique to adjust antennas and maximize tranmission distance.

Then disconnect the lm386 or similar and use with your application. If you want to get even simpler and avoid the audio amp and speaker, use an LED flashing at 1 to 10 hz instead of the audio amp. Be sure to add an appropriate current limiting resistor (220 to 330 ohms for a red LED).

Looks like the little module pairs are only $1.50 from china (including shipping if you can wait 3 to 5 weeks).

what if the duty cycle is not 50:50?

 

http://www.ebay.co.uk/itm/5-pairs-3...396?pt=LH_DefaultDomain_0&hash=item5d3f8c08ac

I don't think I could have clicked the 'BUY NOW" button any faster....

 

Yeah, 5 pairs of TX/RX modules for a total of US $6.14 is pretty good.