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problem in making wireless(door opening system )

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sumeshm.pnr

New Member
hello,
I've built a door opening system. It has interface with the system through serial port of PC.
Now i want to make it wireless. what is my idea is the output from serial port, after converting to TTL logic, is directly transmitted using RF433MHz transmitter.
On RXR side i have connected data pin of RXR directly to 89c51 P3.0(uart). But it is not working..
Is there any problem in direct connection?? what actually the problem is RXR data pin is always high(after it is connected to 8051).
I think it is because while RF RXR data pin is low, it can't pull-down the P3.0 pin to low. I have checked the Txr and RxR, they are working properly.
Is there any problem in this direct connection??. or do i need to do any adjustment in my connection...

please help me,

thanks very much in advance...
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
Generally you require Manchester coding, or some other kind - raw serial data either doesn't work at all, or is unreliable. Assuming serial will work, you may well need a hardware inverter, as it's probably the wrong polarity if you're using a hardware UART in the micro.
 

sumeshm.pnr

New Member
Generally you require Manchester coding, or some other kind - raw serial data either doesn't work at all, or is unreliable. Assuming serial will work, you may well need a hardware inverter, as it's probably the wrong polarity if you're using a hardware UART in the micro.
thanx very much...
 

sumeshm.pnr

New Member
Generally you require Manchester coding, or some other kind - raw serial data either doesn't work at all, or is unreliable. Assuming serial will work, you may well need a hardware inverter, as it's probably the wrong polarity if you're using a hardware UART in the micro.
which IC can i use for Manchester coding????

please give me a brief idea about the schematic...
 

sumeshm.pnr

New Member
please any one help me ......

how can i implement Manchester coding....

i've another idea that uses two 8051 MCU. one at transmitter and other at receiver.

because I've already designed my door opening system(which contains another 8051) the total circuit become very complex.

i want a simple solution that not using micro controllers at transmitter and receiver modules. I've RF transmitter and Receiver modules.
 

Sceadwian

Banned
Sending 01 for 1 and 10 for 0 is a good start. Receiving... Never got a good answer for that.
 

Sceadwian

Banned
Manchester code - Wikipedia, the free encyclopedia
Implementation of Manchester encoding is extremely simple, you XOR the data with a clock.
I've never actually used it (never had a reason) so I have no clue how to go about extracting the clock or syncing the incoming bit stream for receiving. Never looked that far into it.
 
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