Remote Control by cellphone...

[KaJuan]

full duplex serial communication communication

Sir I dont know how full duplex works. All I know is that there is a separate line for TX and another for RX and the last is for gnd. MY question is will there be a time by which the sending and receving of data is done at the same time?

 

[joc_06]

why use full duplex??

It is useful when io pins are a serious issue but a fair few phones dont have provision for it like older ericssons etc.

My advice to you, as i give to all, is to check the website/cd of the micro you are using. The application notes released are the absolute best way to get into the thing and uart is often a major topic...

for more help you'll have to tell me more specifics, like language, micro, phone etc...

 

[KaJuan]

why full duplex mode

The reason why I am using full duplex is that the FBUS cable I am using to connect the phone to my cell phone works in full duplex mode.

 

[csaba911]

I am a 5th Yr. Computer Engineering student.

:shock:

Sir, I have visited your site about pic spicifically the RS232 communications. The tutorial needs the MAIN BOARD that has the PIC16F628. I have notice that board does not include a system clock. Why is this so? Can a microcontroller work even though it does not have a system clock?

:lol:
And I tough I'm beginner!!

Steve

 

[joc_06]

Re: why full duplex mode

The reason why I am using full duplex is that the FBUS cable I am using to connect the phone to my cell phone works in full duplex mode.

You need to do more research. full duplex = mbus, half duplex = fbus (this one is generally acceped to be better option as mbus echoes everything)

 

[nenayd]

How's the progress of your Project?

my project is similar to your project. Silent Security System Sending SMS-alert. I used old ericsson a1018s for the communication and pic16f84a for the processor. In a long period of debugging and hacking the protocol it was now smoothly working. You can search for this gsm model for your project.


p.s. i can provide you some actual tutorials and programming contact me to this no 09173080656.

 

[carlodie]

Re: How's the progress of your Project?

Hi, Somebody can give me information or FBUS MBUS commands????

 

[terka]

Hi

You FBUS cable mybe can set to MBUS

Try it

 

[MEHLULI]

Remote control project HELP NEEDED!

my project is similar to your project. Silent Security System Sending SMS-alert. I used old ericsson a1018s for the communication and pic16f84a for the processor. In a long period of debugging and hacking the protocol it was now smoothly working. You can search for this gsm model for your project.


p.s. i can provide you some actual tutorials and programming contact me to this no 09173080656.

I dont know whether you can help me but from the look of things YES!
My project is also similar. I call the landline (whether home or office) and then toggle on or off the appliances. When a call is made, that is, when ringback tone my system decodes the DTMF signal to BCD then it is demuxed to the flip flops that do the toggling on and off of the appliance connected through relays. Now, I thought I could improve by interfacing a cellphone instead of a landline which is fixed, so as to use it for vehicle security. Now I don't know how I can interface a cellphone, just a simple Nokia 5110 to the whole system. Also, I'm trying to incoporate security features by the PIC16F84 for password to access the system.

PLEASE HELP!
P.S. I AM A FINAL YEAR STUDENT DOING APPLIED PHYSICS!

 

[motion]

Re: full duplex serial communication communication

Sir I dont know how full duplex works. All I know is that there is a separate line for TX and another for RX and the last is for gnd. MY question is will there be a time by which the sending and receving of data is done at the same time?

With a hardware UART in a PIC16F627, there is more than enough time to send and receive at the same time. At 9600 baud, the PIC waits more than 1 msec to send/receive a byte of data. In 1msec, the PIC running at 4Mhz can execute 1000 program instructions, while the hardware UART is sending/receiving data.

With a software UART, you have to service the serial port approximately every 100usec @9600baud. There is not much spare CPU time with a 4Mhz PIC to do full duplex.

However, even if the serial connection is full duplex, the cell phone might not transmitting and receiving at the same time. Or the bytes echoed from the cell phone can be ignored while sending commands to it and so you might get away with a software UART.

 

[emufambirwi]

what if you want to receive a message via rs232 and for the micro controller to act upon that message? Like you need to turn off a relay remotely?

 

[Nigel Goodwin]

Simply program the PIC to act accordingly - check my tutorials for examples.

 

[emufambirwi]

Mr Goodwin,

I have just copied rs232 receive routine and its execllent. I know how to receive a byte using the serial interface.

Rcv_RS232 BTFSC PORTB, 7 ;wait for start bit
GOTO Rcv_RS232
CALL Start_Delay ;do half bit time delay
BTFSC PORTB, 7 ;check still in start bit
GOTO Rcv_RS232
MOVLW 0x08 ;set up to read 8 bits
MOVWF BITCNT
CLRF RCV_BYTE
Next_RcvBit CALL Bit_Delay
BTFSS PORTB, 7
BCF STATUS , C
BTFSC PORTB, 7
BSF STATUS , C
RRF RCV_BYTE , f
DECFSZ BITCNT , f ;test if all done
GOTO Next_RcvBit
CALL Bit_Delay
MOVF RCV_BYTE, W
RETURN


I have a string of bytes like 0x23, 0x54, 0xa5, 0x6a, 0x07, 0x15 stored somewhere in memory ( I don't know whether to put these values in tabular form), but I want to compare the received bytes with the above values sequentially and if exactly similar I branch to section of the code. I hope you can assist me in coming up with code to do the comparison.

 

[Nigel Goodwin]

Check tutorial 5.2 which detects seperate keys, it's easily extended to check for fixed string sequences.

 

[emufambirwi]

I feel that I am failing to understand your tutorial 5.2. Is it possible for you to explain the concept of the code. Or if there is anyone here who can assist I would be grateful.

But consider my suggestion below, assess it and pass you comments.
1 Receive a byte,
2 Save it in a register
3 compare the value in the register with the value in a table

RCVMSGTABLE RETLW 0x1E ; start of incoming msg
RETLW 0x00
RETLW 0x0C
RETLW 0x02
RETLW 0x00
RETLW 0x59
RETLW 0x00
RETLW 0x01
RETLW 0x00
RETLW 0x01
RETLW 0x02
RETLW 0x00
RETLW 0x07
RETLW 0x91
RETLW 0x16
RETLW 0x14
RETLW 0x91
RETLW 0x09
RETLW 0x10
RETLW 0xF0
RETLW 0x00
RETLW 0x00
RETLW 0x00
RETLW 0x00
RETLW 0x15
RETLW 0x00 ;end of incoming msg
So when I receive the first byte in RCVBYTE I compare it with 0x1E, the 2nd received byte with 0x00 , the 3rd with 0x0C etc until the end.

 

[Nigel Goodwin]

Yes, you could keep the string in a table.

 

[emufambirwi]

Yes, you could keep the string in a table.

I have 2 tables that occupies more than 256 addresses, what problems am I likely to face

 

[emufambirwi]

Yes, you could keep the string in a table.

where else could I keep the string

 

[Nigel Goodwin]

You can use long tables, that aren't bothered by 256 byte boundaries - check my LED matrix tutorial.

 

[emufambirwi]

Ok thanks let continue with the code