Simple Digital RF Transmitter and reciever

[Mutad0r]

Hi, I need to transmit a simple 0 or 1 over a very short distance, however I cannot use a wire, so I have to find an RF solution.

I figure PPM is the best solution, the transmitter at least is very easy to create. Since I shouldn't send a simple continious 1 when on and 0 when off I figured a simple 010101 would be enough. I can make a MCU recognize the pattern and timing, the only problem I have so far is turning the alternating RF signal into a 1 and 0.

Basicaly what I'm trying to achieve is very similiar to how the RX2B/TX2B ICs work, I just don't need all the different commands that it can send. I currently have a system using those ICs and it works, but I thought I'd try to figure out a little less wasteful version of it.

So, if anyone knows how the RX2B manages to "clean up" the recieved signal, that would be great.

 

[balakumarcool]

hai friend you can use RF MODULE 433mhz. It has four data pins.the main part of this module is ENCODER,DECODER ICs.So you can transmits four data at a time or receive 4 data at a time

 

[jiripolivka]

Various RF TX/RX modules typically need TTL input and give TTL output. Some require to add a pull-up resistor at output (Open-collector).

At 433 MHz, over a short distance such modules only need quarter-wave antennas to operate but often the transmission fails due to obstacles or multipath propagation. Positions of antennas must be adjusted by trials.

For your case of a distance up to 10-20 meters, if you have a direct line-of-sight between TX and RX position, you can try a light transmission, with a LED or pointer-laser in a black tube, pointed to a photodiode again in a black tube (to reduce ambient light interference). Drivers and output circuits are simpler than those in RF modules, and the system can use IR or visible light for easy installation.

For testing either communication system I used sound, and by listening the output I also achieved a good digital transmission after adjustments.