HELP ME, SMS controlled relay using PIC

[Ioannis]

My suggestion would be to find a phone with AT-command support like many Nokia's and other brands do. Erricson or Siemens of the old school I recall use only PDU format.

Ioannis

[aratti]

Since you said to have already tested a working system using hyperterminal, you should know the basic AT commands!

First of all you will need a phone that is capable of text mode. You will easily check your phone
if is capable of text mode, connecting it to your PC and with hyperterminal send the following AT command "AT+CMGF=1" if answer will be "OK" then you can have a chance to complete your project, if the answer you will obtain will be "ERROR" then your phone use only the PDU mode which need a lot of decoding before you can read the message received. So search a phone that has the text mode.

Before to connect the phone to any PIC device you need to interface the RS232 signal to a TTL in/out this is easily solved using the MAXIM 232

When your hardware is ready you should program your pic using the same AT commands you have used experimenting with hyperterminal as you said.

[pazko1125]

Since you said to have already tested a working system using hyperterminal, you should know the basic AT commands!

First of all you will need a phone that is capable of text mode. You will easily check your phone
if is capable of text mode, connecting it to your PC and with hyperterminal send the following AT command "AT+CMGF=1" if answer will be "OK" then you can have a chance to complete your project, if the answer you will obtain will be "ERROR" then your phone use only the PDU mode which need a lot of decoding before you can read the message received. So search a phone that has the text mode.

Before to connect the phone to any PIC device you need to interface the RS232 signal to a TTL in/out this is easily solved using the MAXIM 232

When your hardware is ready you should program your pic using the same AT commands you have used experimenting with hyperterminal as you said.

thanks. yes it support text mode.
if i send this command using PIC, how can i get the message? do i have to make a variable for it or is it already on the memory?

SEROUT2 TXPIN, BAUD, ["AT+CMGR=1"]
+CMGR: "REC READ","+31625044454",,"07/07/05,09:56:03+08" 'phones reply
Test message 1

can u give a circuit diagram for that. i have circuit diagram here from edaboard.com and i don't know if it will work.

http://www.edaboard.com/ftopic328792.html

[aratti]

yes you will need variables to store the modem answer!

Remember to add 13 at the end of the at command SEROUT2 TXPIN, BAUD, ["AT+CMGR=1",13]

schematic for you project is rather simple because you will use only one pin for output to drive your rele. Since the rele will work at 12 volts and it will require minimum 100 mA you will use a transitor to interface it. I suggest you to use one ULN2803 which is an array of 8 transistor ready for ttl interfacing so you can connect it directly to your pic. Connect all the array, perhaps later you will need an extra rele. Check the data sheet for the other connections.

In writing the software you will need to set up your phone first of all.
ReadTxt:
SEROUT TXPIN, BAUD, ["AT+CMGF=1",13]
SERIN RXPIN, BAUD,5000,ReadTxt, ["OK"],Data

if Data=10 or Data=13 then JumpOut
pause 5000
goto ReadTxt

JumpOut:
ModemOn=1

This routine will set your phone in text mode and will set the variable ModemOn to 1. This is very important because when you will switch of your system I will find this variable very useful.

Second thing you will net is to set the memory place where to read the incoming messages

SEROUT TXPIN, BAUD, ["AT+CPMS=MT",13]

Pause 10000


Now you are ready to check your phone for the presence of sms

Loop:

SEROUT TXPIN, BAUD, ["AT+CMGF=1",13]
SERIN2 RXPIN, BAUD,5000,Loop, [wait("^SMGR:"),str Data\5
if Data[1]=48 and Data[4]=48 then Loop

SERIN2 RXPIN, BAUD,5000,NoSms, [wait("XYZ"),str Data\9

do here your decoding and actions


NoSms:'remove SMS

SEROUT2 TXPIN, BAUD, ["AT+CMGD=1",13]
Pause 1000
goto Loop


Hope it will help

Alberto

[pazko1125]

alberto,

thank you for the coding. just one favor, can you put some comments on this coding. i think it stores the mesage it receive but i can't configure out how it works. thanks again.

Loop:

SEROUT TXPIN, BAUD, ["AT+CMGF=1",13]
SERIN2 RXPIN, BAUD,5000,Loop, [wait("^SMGR:"),str Data\5
if Data[1]=48 and Data[4]=48 then Loop

SERIN2 RXPIN, BAUD,5000,NoSms, [wait("XYZ"),str Data\9

do here your decoding and actions

NoSms:'remove SMS

SEROUT2 TXPIN, BAUD, ["AT+CMGD=1",13]
Pause 1000
goto Loop

[aratti]

Loop:

SEROUT2 TXPIN, BAUD, ["AT+CMGF=1",13] (here you call for a sms)

SERIN2 RXPIN, BAUD,5000,Loop, [wait("^SMGR:"),str Data\5 ( Here you wait for the answer "^SMGR:" data[1] and data[4] are zero then no sms are present so you return to loop)

if Data[1]=48 and Data[4]=48 then Loop

SERIN2 RXPIN, BAUD,5000,NoSms, [wait("XYZ"),str Data\9] ( here you have skipped the if statement, so you have a sms , you wait for "XYZ" which is your password to be sure is your massage . following your pass you should write the coding massage. Remember to write a couple of word [any things you like minimum 10 characters] at the beginning of your massage. Any sms received that does not contain your pass will be ignored)

do here your decoding and actions

NoSms:'remove SMS

SEROUT2 TXPIN, BAUD, ["AT+CMGD=1",13] (Here you delete from phone memory the received sms)
Pause 1000
goto Loop

Hope to have cleared

Alberto