How to interface the 8051 with the RF transmitter?

[huiyen]

8051 rf

I want to transmit digital signal(3 bits) between Radio frequency transmitter and Receiver for control the movement server motor. How to go about writing a program for it and how to interface between the micrcontroller and the transmitter. Any source code or info on this ?

 

[rajeshkumar123]

8051 rf module

Hi,

The source code varies according to the RF transmitter module. Some module uses a SPI other uses a UART so you need to study the datasheet before starting to write code.

With Regards
S.Rajesh Kumar

 

[huiyen]

interfacing 8051 with rf transmitter

That is the transmitter datasheet.Can u help me to check it?It is use SPI or UART? Thanks

 

[hamed_sotoudi]

how to connect rf transmitter to microcontroller

Hi
your tramsmitter supporte up to 10kbps so connect it to your microcontroller usart port then set its speed for example to 8kbps( dont set to maximum speed that transmitter support maybe most of data in noisy conditions lost). then it is better to write a simple protocol for sync transmitter with reciever for example for sending a command first send "AA" in hex then send your command then send "55" in hex and in your reciever command is correct if u recieved at first "AA" then a byte of data and after that "55" in hex.

good luck.

 

[microlab]

rf transmitter with 8051

dear friend

please assure that the rf module (mainly at the receiver side)
is power ful enough to bting down the level from 1 to 0
normally the receivers are not that much powerful to do so
when u r connecting the system directly to the uart of the mcu
it's necessary to check the same
you may use any buffer to solve the problem
secondly,there's a possibility of junk(unwanted) data recd
please take care of it

regards

ml

 

[vigneshwara_s]

rf module to microcontroller

Hi ...

For interfacing 8051 with RF Transmitter .. U can better go for serial port based transmission.

Connect the TX line of the Micro controller to the Transmitter . While writing the

code .. it is simple for you to use it as serial port . Just out the charecter in the

serial port with the Baud rate ur microcontroller support .

There is no special code needed other than normal UART code for transmitting

data in serial port thro RF .

At the reciever end jus connect the RX pin of the reciever [Mc or PC] and get the

data in UART protocol...[][]

Hope this will give u a better idea ..

Thanks and regards ,

S.Vigneshwaran @ vikee...

 

[ctownsend]

rf transmitter with microcontroller

it was discussed here:


someone also posted a link with source code

 

[huiyen]

transmitter using 89c51

then how can i test that transmitter TX9912 before start the project?got any idea? how to connect the circuit and testing that transmiter?

 

[ctownsend]

working of rf module with microcontroller

then how can i test that transmitter TX9912 before start the project?got any idea? how to connect the circuit and testing that transmiter?

The datasheet you posted indicates that the data rate is 9600 bps.

I would test the transmitter by repeatedly sending a character out the serial port @ the specified baud rate.

I would send 55 AA in a continuous loop until you get the receiver to detect it properly.

IF you are having difficulty, you can always use a Holtek Encoder/Decoder pair of IC's for the encoding/decoding which makes things a great deal easier. All you have to do is send a byte to the encoder and it does the encoding/decoding for you for trouble free, noise free, RF transmission/reception. I used them it in one of my RF projects, and it made the world of difference for preventing lost data.

Do a google search for HT12E (encoder) HT12D (Decoder).

All of the above assumes you know how to write code for the microcontroller uart.

Good Luck

 

[huiyen]

rf transmitter ,8051

does u means need to use the HT12E (encoder) and Transmitter together for transmit data? HT12D (Decoder) and receiver for receive data?do u got the code?if yes,can you send to me?

 

[ctownsend]

interface microcontroller transmitter

the HT12E (encoder) would work with the transmitter.
the HT12D (decoder) would work with the receiver.

Normally these IC's do not require the use of an added microcontroller, However I used them with an 8051 microcontroller to send/receive 4 bit data using the four pins. With the encoder you can send 4 bits to the encoder or just work with one bit at a time. Whatever pins are cleared or set, the same will appear on the decoder's 4 pins.

The eight address pins on the encoder must match the same on the decoder. So you can tie every odd one low, or whatever you want, does not matter as long as it matches the other side.

Setup the data on the four pins D8 - D11.
(data command from 0 to 0x0F (4 bit) then bring TE low,
and the encoder does the rest, its real easy!

On the receiver side, monitor VT line, if it goes high, valid data received - read the data pins D8 - D11.
and mask off the upper nibble, or you can just read each pin instead. There are four pins.

Best for you to look at the datasheet. There are circuits and diagrams explaining usage.
decoder:
**broken link removed**
encoder:
**broken link removed**

Remember you do not need to use a microcontroller with these units, I did because I wanted to send commands ranging from 0 - 0x0F.

Good Luck

 

[hamed_sotoudi]

source code to send data pc to ht 12 d

Hi
Connect transmitter to one of micro pins and write a simple code that only generate a simple pulse with low frequency then in other side connect vcc and ground to reciever and in its data pin check that pulses . if you can get pulse every thing is ok.

 

[sandip_047]

rf interface with 8051

You Can put your data in SBUF and send it on RS232 Tx pin, which will be connected to your rf tx's data pin.
At Rx connect Your RS232 rx pin to RF RX's data out pin.
Write code for serial com and you will get what you want.

 

[barathrajamani]

rf 8051

i have a question..
is it good to have a fm transmision from the sensor to the micocontroller or from the MC to the lcd display

 

[ctownsend]

rf module with microcontroller

is it good to have a fm transmision from the sensor to the micocontroller or from the MC to the lcd display

The answer would entirely depend on what type of sensor you have. What I would do is use a small cheap MCU (8 pin avr or something) to receive the sensor data and send the data wirelessly to the other mcu that displays the data on the LCD display.

 

[ctownsend]

ht12e interfacing

What is the sensor you have? Post a datasheet or a diagram and all the information you can so that someone may help you out.

 

[sharang]

rf module interface to microcontroller

Hi,
we have made a circuit consisting of two 8052's and are achiving rf communication between them using rf module 315Mhz....but at the reciever we are getting garbage values....wat to do...will ht12d and ht12e help....if yes how to interface them

 

[ctownsend]

how use module rf microcontroller

....but at the reciever we are getting garbage values....wat to do...will ht12d and ht12e help....if yes how to interface them

The receiver will always receive garbage data. It is dependent on the software to filter out the data. If you use the holtek pair, it takes care of the data for you. Look at my post above to find out how to use them.

 

[sharang]

interfacing rf encoder to 8051 c code

We are using 8052 at transmitter also which gives serial data and ht12e requires parallel inputs....so i connected tx pin of 8052 to all data pins of ht12e...and output data pins of ht12d to rx pin of 8052...dout and din pins of ht are connected to rf modules.....still getting garbage wih VT pin high

Added after 28 minutes:

we have also tried various baud rates still no improvement.....

 

[ctownsend]

rf modules interface with 8051

....so i connected tx pin of 8052 to all data pins of ht12e...and output data pins of ht12d to rx pin of 8052...dout and din pins of ht are connected to rf modules.....still getting garbage wih VT pin high

that is TOTALLY wrong. Please read the schematic of the ht12e and the ht12d. There it shows how to hook up the encoder/decoder to a microcontroller.