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Is it a inteference problem or PIC problem?

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sysysy

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Hello everyone,

i use PIC16f877A USART to do my full duplex communication between 2 controllers....

Initially, i use jumpers, and the communication work well.
Then when i proceed this to RF modules (wireless communication)

then problem start occur. OK, since it is full duplex, so i use different frequencies of module which is one 315MHz pair and another one 433MHz pair. The problem the communication become invalid data received.

After do some troubleshooting, i found that if i only use 1 pair RF module and another way use jumper, the system work well again.... from there, i start suspect is interference problem again since, when two pair RF modules are not used together, system will work well.

But one thing i not sure is, why i already use two different frequencies modules, interference problem still occur? Or this may other problem? Can anyone give me advice and solution, thanks thanks.
 

microlab

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hi

are you using same antenna for both the modules?
you can use some electronic switches to switch on/off the pairs which are not in use

ml
 

sysysy

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Yupe...for 315MHz, i use 24cm long antenna and for 433MHz pair, i use 18cm long antenna

hmmm, since it is both ways communication, so both modules should be in use all the time, what do you mean which using electronics switch? such as Transistor?

but may i know how to implement this?
 

microlab

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hi

something like a transistor
you know when the modules to be functioned and switch on the module which is used, and switch off which is not used. .and normally the 315 and 433 mhz modules does not interface each other.
may be this is happening because of the position of the modules you placed. you can try changing the position of the antenna.keep them a little more distance.you can use some modules with built in tranceiver like modules with CC2500 etc
but you cannot use the for full duplex.
ml
 

sysysy

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do u mean antenna distance between 315 TX and 433 RX and vice versa?
 

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