Problem with wireless serial transmisson

[colin mac]

But actually I want to control Two DC motors and also want to control the speed of DC motor that I think can be done with the help of micro controller only.

But I not understand that RF modules work fine with HT12E and HT12D. Then what is problem with AT89C51??

-----------------
Regards
Gaurav Sharma

There is no problem if you can implement the code. RF modules need a bit balanced data signal to be fed to them, like Manchester Coding.

 

[gaurav_sharma132]

then what is possible remedy to it.....?


----------------
Regards
Gaurav Sharma

 

[colin mac]

Use the encoder and decoder I suggested with your micrcontollers.
Or study Manchester Coding with RF modules.

 

[gaurav_sharma132]

Use the encoder and decoder I suggested with your micrcontollers.
Or study Manchester Coding with RF modules.

Ok You mean If not want to use Manchester coding the use encoder/decoder......
and if not want to use encoder/decode then use Manchester coding.....
Right ???

--------------
Regards
Gaurav Sharma

 

[colin mac]

Ok You mean If not want to use Manchester coding the use encoder/decoder......
and if not want to use encoder/decode then use Manchester coding.....
Right ???

--------------
Regards
Gaurav Sharma

Yes, if they are suitable for your application as those chips handle the coding for you.

 

[gaurav_sharma132]

Tell me one thing is Encoder/decoder have inbuilt line coding like menchester as they don't need any kind of coding to be implemented externally???

--------------
Regards
Gaurav Sharma

 

[Nigel Goodwin]

Tell me one thing is Encoder/decoder have inbuilt line coding like menchester as they don't need any kind of coding to be implemented externally???

Yes, the encoder/decode includes Manchester, or something that does the same job. Ignore the Holtek chips, they aren't what you want - but the module manufacturers make specific encoder chips that allow you to feed your normal serial from the 8051. They even sell modules with the chips built-in.

 

[gaurav_sharma132]

Yea, I already bought the encoder/decoder chips available at
**broken link removed**

From this I also bought ask modules as I said earlier.

So now I have to interface it with micro controller and block diagram becms

transmitter (AT89C51) pin 11 i.e TXD --->> Encoder---->>434MHz ASK

Transmitter Module--->>wireless medium--->434MHz ASK Receiver

Module--->>Decoder ---->>Receiver(AT89C51) pin 10 i.e RXD--->> L293D

Driver--->> control motors

right na??


----------------
Regards
Gaurav Sharma

 

[Nigel Goodwin]

Yes, or just write software routines for your 8051's to do the encoding/decoding.

But as I've repeatedly said, if you fit simple inverters it may well work well enough for you anyway.

 

[gaurav_sharma132]

we have to do special programing for encoding/decoding in 8051 or it is a function of encoder/decoder chip itself to encode n decode data??

Abt data inverting I am reading your tutorial.....lets hope get somethng good

In your tutorial you are talking about PC RS232 port or micro controller serial pin ???

--------------
Regards
Gaurav Sharma

 

[colin mac]

Ignore the Holtek chips, they aren't what you want .

Why aren't they? You can send 4 bit data to the HT12E, which is 16 different commands. All he is doing is controlling a few motors.

 

[Nigel Goodwin]

Why aren't they? You can send 4 bit data to the HT12E, which is 16 different commands. All he is doing is controlling a few motors.

They are simple remote control chips, not for sending data - presumably he wants to send more than they provide, or why bother using a microcontroller?.

 

[gaurav_sharma132]

But actually I want to control Two DC motors and also want to control the speed of DC motor that I think can be done with the help of micro controller only.


------------
Regards
Gaurav Sharma

 

[colin mac]

They are simple remote control chips, not for sending data - presumably he wants to send more than they provide, or why bother using a microcontroller?.

They send 4-bit data. They aren't designed for high data rates sure. Using a microcontoller, two nibbles can be combined to send a byte very easily. Much easier than writing a Manchester decoding and encoding program.

 

[gaurav_sharma132]

we have to do special programing for encoding/decoding in 8051 or it is a function of encoder/decoder chip itself to encode n decode data??


-----------------
Regards
Gaurav Sharma

 

[gaurav_sharma132]

To Nigel Goodwin,

In your tutorial you are talking about PC RS232 port or micro controller serial pin ???


--------------
Regards
Gaurav Sharma

 

[Nigel Goodwin]

To Nigel Goodwin,

In your tutorial you are talking about PC RS232 port or micro controller serial pin ???

In the wireless tutorial, it's referring to the micro-controller pin, and just a general I/O pin, a hardware UART is pretty useless for this application.

 

[Nigel Goodwin]

They send 4-bit data. They aren't designed for high data rates sure. Using a microcontoller, two nibbles can be combined to send a byte very easily. Much easier than writing a Manchester decoding and encoding program.

But you're adding extra hardware, slowing things down, and drastically reducing functionality. Manchester routines with a suitable packet size are so much more versatile, and require no extra hardware.

 

[gaurav_sharma132]

I have read your tutorial they are explaining Manchester code...

But now question arises how to implement that...??

Also please respond to post #35..........


--------------
Regards
Gaurav Sharma

 

[Nigel Goodwin]

we have to do special programing for encoding/decoding in 8051 or it is a function of encoder/decoder chip itself to encode n decode data??

I thought it was pretty obvious?, an encoder/decoder chip does the encoding/decoding - the clue is in the name.

Try this page for an example, and links to datasheets: