How to control servo motor with handphone through GSM modem?

[supertyx]

Hi all,

I am currently doing a mini project of controlling the servo motor using easypic4.

I managed to control the direction the servo turns by using the pushbuttons on the board to make it turn clockwise or counter-clockwise.

However, I would like to control the servo by sending a message using handphone to the GSM modem which is connected to the RS232 com port of the easypic4 and make the servo turns accordingly.

What are the additional codes which I need to control using handphone?

Any help would be appreciated. Thanks. =)

[skimask]

I am currently doing a mini project of controlling the servo motor using easypic4.
I managed to control the direction the servo turns by using the pushbuttons on the board to make it turn clockwise or counter-clockwise.
However, I would like to control the servo by sending a message using handphone to the GSM modem which is connected to the RS232 com port of the easypic4 and make the servo turns accordingly.
What are the additional codes which I need to control using handphone?

Wow.........

[Ioannis]

I could say a lot of additional code...

In this special category on GSM there are many examples... Just search through. I warn you it is not an easy project...

Ioannis

[supertyx]

First I wrote a couple of codes to test the AT commands with SEROUT2 and Tx Command between my PC and the PIC16F77A (CPU) on the easypic4 using hyperterminal.

These are the codes:

INCLUDE "modedefs.bas"

'PIC16F877A specific

@ __CONFIG _HS_OSC & _WDT_ON & _LVP_OFF & _CP_OFF

'This is a simple program to drive a servo using easypic4 and pushbuttons.
'PORTB.0 - Set to drive the servo clockwise to the center.
'PORTB.1 - Set to drive the servo clockwise to the end.
'PORTB.3 - Set to drive the servo counter-clockwise to the end.

'Connections:

'PIC-PIN : Servo
'PortC.1 : Control wire
'Vcc(5V) : Power Wire(Red wire)
'Gnd(0V) : Black wire

'************************************************* *********************

'Defines

Define LOADER_USED 1 'Use tiny boot loader

DEFINE USE_LFSR 1
DEFINE OSC 20

' LCD Defines
DEFINE LCD_DREG PORTD ' LCD data port
DEFINE LCD_DBIT 4 ' LCD data starting bit 0 or 4
DEFINE LCD_RSREG PORTD ' LCD register select port
DEFINE LCD_RSBIT 2 ' LCD register select bit
DEFINE LCD_EREG PORTD ' LCD enable port
DEFINE LCD_EBIT 3 ' LCD enable bit
DEFINE LCD_RWREG PORTD ' LCD read/write port
DEFINE LCD_RWBIT 2 ' LCD read/write bit
DEFINE LCD_BITS 4 ' LCD bus size 4 or 8
DEFINE LCD_LINES 2 ' Number lines on LCD
DEFINE LCD_COMMANDUS 2000 ' Command delay time in us
DEFINE LCD_DATAUS 50 ' Data delay time in us

'Set tris & system registers


TRISA=%00000000 ' Set Port A pins as Output
TRISB=%11111111 ' Set Port B pins as Input
TRISC=%00000000 ' Set Port C pins as Output
TRISD=%00000000 ' Set Port D pins as Output
TRISE=%00000000 ' Set Port E pins as output

'Program variables

position var byte

'Input/output port assignments

PB_UP VAR PORTB.3 'Push button to move servo up
PB_center VAR PORTB.0 'Push button to move servo to center
PB_down VAR PORTB.1 'Push button to move servo down

Tx var PORTC.6 ' Tx Rs232 to Terminal
Rx var PORTC.7 ' Rx Rs232 from Terminal

'Main program

PORTC.1 = 0

InitModem:
pause 1000
lcdout $Fe,01,"Init Modem"
gosub init

pause 1000
lcdout $Fe,01,"Modem Init Done"
pause 1000

lcdout $FE, 01, "Ready to start"

'Read input

Read_input:

if PORTB.0 = 1 then
position = 0

endif

if PORTB.1 = 1 then
position = 1

endif

if PORTB.3 = 1 then
position = 2

endif

if position = 0 then
pulsout PORTC.1, 750

endif

if position =1 then
pulsout PORTC.1, 300

endif

if position =2 then
pulsout PORTC.1, 1150

endif

pause 50

goto Read_input

'SMS subroutines


Init:

' Subroutine to initialise the GSM modem

Serout2 Tx,84,["AT+CLIP=1",13] ' CLIP command
Pause 500
Serout2 Tx,84,["AT+CNMI=3,0",13] ' SMS now not polled
Pause 500
Serout2 Tx,84,["AT+CMGF=1",13] ' Set Text Mode
Pause 500

SERout2 Tx,84,["AT+CMGS=",34,"+6598755989", 34,13]

'Preferred Message Storage: ME on Phone

Serout2 Tx,84,["AT+CPMS=",34,"ME",34,13] ' Changed for GR47
Pause 4000

'Set the storage to SIM

Serout2 Tx,84,["AT+CPBS=",34,"SM",34,13]' Otherwise cannot read memory location
Pause 1000

'SERIN2 Tx,84,5000,Problem,[Wait ("OK")] ' Loopback to NotReady
'Select Character Set “UTF-8” : Universal text format, 8 bits

PAUSE 1000
Serout2 Tx,84,["AT+CSCS=",34,"UTF-8",34,13] ' for @ sign problem
pause 1000
Serout2 Tx,84,["AT&W",13] 'Store User Profile to non volatile memory
pause 1000
Serout2 Tx,84,["AT+CMGD=1,4",13]
pause 3000

Return


Next I need to change the above codes to SERIN and Rx and "additional codes" so that my GSM modem can receive an sms from a handphone in order to trigger the servo motor.

This is where my problem comes in. Any help would be appreciated. Thanks.

[Ioannis]

I would strongly suggest to use hardware USART and if possible interrupts like Darrels Instant Interrupts. It will assure you no lost characters.

Secondly, I see that you are not checking if the modem has replied with OK or an error, except once. Not all commands have the same processing time. So it is a good practise to confirm that the device has accepted succesfully the command by monitoring its response.

Ioannis

[supertyx]

I would strongly suggest to use hardware USART and if possible interrupts like Darrels Instant Interrupts. It will assure you no lost characters.

Secondly, I see that you are not checking if the modem has replied with OK or an error, except once. Not all commands have the same processing time. So it is a good practise to confirm that the device has accepted succesfully the command by monitoring its response.

Ioannis

I've used an open source software called " real term" to test out the serial cable

The following are the codes i used to test:

    Serout2 Tx,84,["Ready:",13]
	pause 500
	Serin2 rx,84,[wait("A="),B0]				
	Pause 500
    Serout2 PORTC.6,84,["Got: ",B0,13]
	pause 500
	goto init

It's working. Now I need to test the GSM modem using SEROUT2 and SERIN2 commands. Anyone knows how?

[Ioannis]

Any special need to use Serin2/Serout2 instead of Hseri/Hserout?

Ioannis

[supertyx]

Any special need to use Serin2/Serout2 instead of Hseri/Hserout?

Ioannis

What are the differences between serin2/serout2 and hserin/hserout?

How can I use either set of commands to capture sms message?