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Author Topic: doubt on coding for wireless data exchange  (Read 1417 times)

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Offline subhechhaTopic starter

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doubt on coding for wireless data exchange
« on: January 06, 2011, 11:08:52 AM »
hii.....everyone...i have to make two line follower bots which would have ability to transfer in single direction,the coordinates .so for that i have got a rf module transmitter and receiver of 433mhz along with encoder ht12e and decoder ht12d...m using atmega16 and would program on avr studio4.can anyone really help me out by sending me the code for it and along with the circuit for encoder and decorder....its because i can find nowhere from internet the circuit and program for rf module using encoder and decoder.....
one more question need to be asked is whether usart code can be used for wireless transmission and reception purpose?? plz reply soon...

Offline waltr

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Re: doubt on coding for wireless data exchange
« Reply #1 on: January 06, 2011, 12:49:57 PM »
I found several circuits for using these encoder and decoder chips with google.

They are intended to work with each other so that when a button is pressed on the encoder the decoder changes an output. They do not need a processor.

If you wish the send other data from one Bot to the other then you don't use these encoder/decoder chips. Instead you send serial data out of the processor into the transmitter to send and out of the receiver into the other processor.
You haven't given us which 433MHz RF modules you are using but I'll guess they are one of the low cost modules. These typically use OOK modulation therefore the serial data should use an encoding method to ensure the serial bits change (no continuous 1's or 0s).

Google the terms:
OOK modulation
Manchester encoding

The UART in the processor can be used if the data is pre-encoded or bit-bang the data output of a port pin.
And here is a link using this type of RF modules on a:
http://letsmakerobots.com/node/12336

The VirtialWire code does work very well and is the correct way to send data on these RF modules.

 


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