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Michael Karas
09/04/12 11:34
Read: 790 times
Beaverton Or

#188228 - Half Duplex
Responding to: David Prentice's previous message
David Prentice said:
Those 433MHz modules are fairly cheap. The 2.4GHz NRF24L01+ modules are even cheaper.

In theory, 433MHz should give a better range. However any RF comms requires a lot or error detection / correction for a reliable link.

So as well as the Manchester encoding, you need an extensive software layer. The NRF24L01+ (and the 8051 versions) handles the channel, pipe, CRC, ACK, power, ...

In practical terms, which would be more reliable ?
< 20m in a cluttered office
< 20m in a cluttered factory floor.
< 100m in a clear field.


RF that would support full duplex multi-point communications gets rather complex. I was using half duplex in a manner that was very simple and sent only once per minute. Guarenteed delivery of information was not required as there was always another message coming in the next minute and the recipient devices were capable if sustaining operation even if the RF updates were absent of corrupted for hours or more.

Michael Karas

List of 14 messages in thread
sample source code 433Mhz rf remote C soure code       Vaka Kiran Kumar      09/03/12 06:13      
   Which RF module are you using? ... provide a link, please      Richard Erlacher      09/03/12 10:33      
   Eh??      Andy Neil      09/03/12 14:13      
      RF remote      Vaka Kiran Kumar      09/03/12 22:04      
         Are You Willing....      Michael Karas      09/03/12 23:26      
         A Manchester Modulation Scheme      Michael Karas      09/04/12 01:14      
         Manchester RF Receiver      Michael Karas      09/04/12 01:22      
         Manchester RF Transmitter      Michael Karas      09/04/12 01:27      
            How effective is the 433MHz      David Prentice      09/04/12 03:14      
               Half Duplex      Michael Karas      09/04/12 11:34      
         Where's the link to the datasheet?      Richard Erlacher      09/04/12 08:38      
            please fined teh atatched zip      Vaka Kiran Kumar      09/05/12 04:42      
               Please provide access to your C: drive      Erik Malund      09/05/12 07:10      
               Hacking activated        Per Westermark      09/05/12 08:21      

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