RF Tx,Rx Module ASK

[ahmedragia21]

Hi, im trying to use an RF Tx,Rx Module which uses ASK modulation at 433Mhz carrier .. how do i test its output ? i put a simple LED and tried to transmit some bits by a wire and it does reciever but there's some noise i feel it in the output led why is that ? i dont have a scope nor a function generator to test that really .. also i send 5V ampiltude why at the reciever the amplitude is 3V or less ? also can i send a byte without any noise or error , im really scared of that cuz i dont trust wireless or anything , dont know why ... and how to avoid noisy bytes or signals ? can i also send a byte and recieve it using this module like from serial PC to tx - Rx -> Pc ?

Thanks Alot in advance !

 

[erosennin]

Do you have a scanner? Tune it to the frequency, send something while recording the scanner output and view it on something like Audacity - assuming the material you transmitt is <20khz.

The noise may be due to poor shielding. I don't quite understand how you 'feel it in the output led'...
Could we have a schematic please?

Yes you can use the PC to send serial information - you can use Hyperterminal, comes free with Windows.

 

[ahmedragia21]

The noise may be due to poor shielding. I don't quite understand how you 'feel it in the output led'...

The led just emitts random light , like dancing , not quite steady , sorry am non-native ..

Could we have a schematic please?

its the usual RF module 433MHz
https://www.sparkfun.com/commerce/product_info.php?products_id=715]

Yes you can use the PC to send serial information - you can use Hyperterminal, comes free with Windows.

no i mean , Send serial data from pc using that RF Module without any additional things ?

 

[ahmedragia21]

The noise may be due to poor shielding. I don't quite understand how you 'feel it in the output led'...

The led just emitts random light , like dancing , not quite steady , sorry am non-native ..




Could we have a schematic please?

its the usual RF module 433MHz
https://www.sparkfun.com/commerce/product_info.php?products_id=715]




Yes you can use the PC to send serial information - you can use Hyperterminal, comes free with Windows.

no i mean , Send serial data from pc using that RF Module without any additional things ?

 

[Nigel Goodwin]

Check my PIC tutorials, which show one way to use them - bear in mind such modules are AC coupled, not DC.

 

[ahmedragia21]

so the soultion is to invert the uart signal ?

 

[Nigel Goodwin]

so the soultion is to invert the uart signal ?

It's a very crude solution, the better way is to use Manchester coding.

 

[ahmedragia21]

Hi again , i want to know a simple experiment to test that module ... send a byte from the micro and recieve it at another micro ...

 

[Norlin]

I've used this module this past week and found that if the transmitter and receiver are too close together (within about 6 feet of each other) the transmitter "overpowers" the receiver and you get a whole bunch of garbage on the receiving end. Also, attaching a small helical antenna to both the transmitter and receiver got rid of a lod of errors and garbage I was seeing, here's a link where I was talking about my results:
https://forum.sparkfun.com/viewtopic.php?t=9883

I was using a PIC uC to send a "Test" string ever 0.5s and receiving them on a PC with hyperterminal hooked to the receiver via a MAX232 IC.