In an earlier article, I explained how a single switch can be controlled by using a simple IR transmitter and a simple receiver circuit. This article explains how to extenmd the same concept to control a number of switches.
Now, as more than one switches are to be controlled, we have to transmit a number of bits through IR transmission to indicate which is key is pressed on the remote and accordingly which switch of the switch-board to control. In this project, this is done by using a ready-made IR remote control which works on RC5 protocol.
RC5 protocol was developed by Phillips for controlling consumer electronics such as TV, VCD-DVD Player,etc. through IR Remote Controller. This type remote controller can be found in Phillips' 90 channel TVs. This is a very popular IR protocol and very easy to understand.
Basically, in a RC5 protocol, when a key on the remote controller is pressed, a total of 14 bits are serially transmitted. This includes 2 Start bits, 1 Toggle bit, 5 Address bit and 6 Data bit. These 14 bits are transmitted on a carrier of 38/36 khz carrier by using Manchester Coding. High and Low time are 889 us. For more on Manchester Coding and RC5 protocol, read this.
At the receiver, TSOP1738 receiver is used. It removes the carrier and provides serial data. This serial data is applied to AT89C51 microcontroller for decoding serially transmitted data and control the output accordingly. Relays are used for switching action and they are controlled by the microcontroller through the ULN2803 IC. Circuit diagram is shown below :
Source code of the project is given below. It is in assembly language.
;Program assuming following dataset from receiving side
;
;
; button signal hex
; 1 1 0 00000 011110 111 1E
; 2 1 1 00000 011101 111 1D
; 3 1 0 00000 011100 111 1C
; 4 1 1 00000 011011 111 1B
; 5 1 0 00000 011010 111 1A
; 6 1 1 00000 011001 111 19
; 7 1 0 00000 011000 111 18
; 8 1 1 00000 010111 111 17
; 9 1 0 00000 010110 111 16
; STDBY 1 1 00000 010011 111 13
CNT equ r7 ;Temporary Variable
EXCNT equ 10H ;Count
ADDRS equ 11H ;Device address
CMD equ 12H ;Command
ATEMP equ 13H ;Temperory store
TEMP equ 14H ;Temperory store
DLOCK equ 15H ;Setting lock permission
OTOG bit 00H ;Flip bit
TOG bit 01H ;Temp bit for flip
IR equ P1.1 ;IR Receiver connected to this pin
SWPORT equ P0 ;Port at which switches are connected
DSPPORT equ p2 ;Display port
CH1 equ p2.0 ;Signal Waiting bit (determine whether controller is busy or not)
CH2 equ p2.1 ;Successfull command
CH3 equ p2.2 ;Lock status indicator
org 0000H ;Start of prog
mov SWport,#00H ;switch all relays off!
mov DSPPORT,#00h ;Setting display off
mov sp,#50H ;Stack pointer initialization
clr TOG ;Clear temp bit
mov DLOCK,#02H ;Setting lock off
setb CH3 ;Dispalying default status as an unlocked
main:
jb IR,main ;Wait for first bit
clr CH1 ;Reseting to indicate Busy
mov CNT,#225 ;Reading the start bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#216
djnz CNT,$
mov c,IR
mov CNT,#225 ;Reading the toggle bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
mov TOG,c
mov EXCNT,#04h ;Reading 4 address bits
mov a,#00h
adloop:
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
djnz EXCNT,adloop
mov CNT,#225 ;Reading 5th address bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#180
djnz CNT,$
mov c,IR
rlc a
mov ADDRS,a ;Storing ADDRESS
mov a,#00h
mov CNT,#225 ;Reading first data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
clr c ; It is always 0 received
rlc a
mov CNT,#225 ;Reading second data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
setb c ;It is always 1 received
rlc a
mov CNT,#225 ;Reading third data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ;Reading forth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ;Reading fifth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ; Reading sixth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CMD,a ;Storing command
mov a,ADDRS ;Validation 1
cjne a,#00h,eop1
mov a,#00h ;Converting both toggles to byte
mov c,OTOG
rlc a
mov TEMP,a
mov c,TOG
mov a,#00h
rlc a
cjne a,TEMP,cont1 ;Validation 2
jmp eop1
cont1:
mov c,TOG
mov OTOG,c
mov TEMP,#00h
mov a,CMD ;Converting command to equivalent decimal count
cjne a,#1Eh,skip1
mov TEMP,#01h
skip1:
cjne a,#1Dh,skip2
mov TEMP,#02h
skip2:
cjne a,#1Ch,skip3
mov TEMP,#03h
skip3:
cjne a,#1Bh,skip4
mov TEMP,#04h
skip4:
cjne a,#1Ah,skip5
mov TEMP,#05h
skip5:
cjne a,#19h,skip6
mov TEMP,#06h
skip6:
cjne a,#18h,skip7
mov TEMP,#07h
skip7:
cjne a,#17h,skip8
mov TEMP,#08h
skip8:
cjne a,#13h,cont2 ;Switching off SWPORT
jmp offall
cont2:
cjne a,#1Fh,cont5 ;Checking for lock signal
jmp checklock
cont5:
mov a,TEMP ;Validation 3
cjne a,#00h,cont3
eop1:
jmp eop
cont3:
mov a,DLOCK ;Validation 4
cjne a,#02h,eop
clr c ;Inverting SWPORT bit as per count
mov a,TEMP
mov CNT,a
mov a,SWPORT
again1:
rrc a
djnz CNT,again1
mov ATEMP,a
mov a,#00h
rlc a
cpl a
rrc a
mov a,TEMP
mov CNT,a
mov a,ATEMP
again2:
rlc a
djnz CNT,again2
mov SWPORT,a
setb CH2 ;SWPORT written indicator
jmp cont4
offall: ;SWPORT off sub module
mov a,#00h
mov SWPORT,a
cont4:
jmp cont6 ;Check lock sub module
checklock:
mov a,DLOCK
cjne a,#02h,incmt
mov DLOCK,#00h
clr CH3
jmp cont7
incmt:
inc DLOCK
cjne a,#01,cont8
setb CH3
cont8:
cont7:
cont6:
eop:
mov EXCNT,#40
loop1:
mov CNT,#255
djnz CNT,$
djnz EXCNT,loop1
setb CH1 ;Seting to indicate as Ready
clr CH2 ;Clearing as default state
ljmp main
end
The code works by sampling data input pin at certain intervals and stores data in registers. After that, according to received data bits, switches are controlled. For example, if '1A' is received, then switch no 5 will be toggled. Similarly, if '17' is received, then switch no 8 will be toggled. Apart form this, if a '0' is pressed once, then it locks the device. If a device is locked, status of switches cannot be changed. For unlocking device, you have to press '0' button twice. After that, it will resume normal operation. Also, when 'STD BY' key of remote is pressed, then all the switches are turned off regardless of their previous state.
This is a very easy to make and fun to use project. You can use it in your house for controlling switches of the switchboard. If you have any problem regarding making this project or want to give Feedback, then post a comment here or mail me at dmehta17@gmail.com.
Now, as more than one switches are to be controlled, we have to transmit a number of bits through IR transmission to indicate which is key is pressed on the remote and accordingly which switch of the switch-board to control. In this project, this is done by using a ready-made IR remote control which works on RC5 protocol.
RC5 protocol was developed by Phillips for controlling consumer electronics such as TV, VCD-DVD Player,etc. through IR Remote Controller. This type remote controller can be found in Phillips' 90 channel TVs. This is a very popular IR protocol and very easy to understand.
Basically, in a RC5 protocol, when a key on the remote controller is pressed, a total of 14 bits are serially transmitted. This includes 2 Start bits, 1 Toggle bit, 5 Address bit and 6 Data bit. These 14 bits are transmitted on a carrier of 38/36 khz carrier by using Manchester Coding. High and Low time are 889 us. For more on Manchester Coding and RC5 protocol, read this.
At the receiver, TSOP1738 receiver is used. It removes the carrier and provides serial data. This serial data is applied to AT89C51 microcontroller for decoding serially transmitted data and control the output accordingly. Relays are used for switching action and they are controlled by the microcontroller through the ULN2803 IC. Circuit diagram is shown below :
Source code of the project is given below. It is in assembly language.
;Program assuming following dataset from receiving side
;
;
; button signal hex
; 1 1 0 00000 011110 111 1E
; 2 1 1 00000 011101 111 1D
; 3 1 0 00000 011100 111 1C
; 4 1 1 00000 011011 111 1B
; 5 1 0 00000 011010 111 1A
; 6 1 1 00000 011001 111 19
; 7 1 0 00000 011000 111 18
; 8 1 1 00000 010111 111 17
; 9 1 0 00000 010110 111 16
; STDBY 1 1 00000 010011 111 13
CNT equ r7 ;Temporary Variable
EXCNT equ 10H ;Count
ADDRS equ 11H ;Device address
CMD equ 12H ;Command
ATEMP equ 13H ;Temperory store
TEMP equ 14H ;Temperory store
DLOCK equ 15H ;Setting lock permission
OTOG bit 00H ;Flip bit
TOG bit 01H ;Temp bit for flip
IR equ P1.1 ;IR Receiver connected to this pin
SWPORT equ P0 ;Port at which switches are connected
DSPPORT equ p2 ;Display port
CH1 equ p2.0 ;Signal Waiting bit (determine whether controller is busy or not)
CH2 equ p2.1 ;Successfull command
CH3 equ p2.2 ;Lock status indicator
org 0000H ;Start of prog
mov SWport,#00H ;switch all relays off!
mov DSPPORT,#00h ;Setting display off
mov sp,#50H ;Stack pointer initialization
clr TOG ;Clear temp bit
mov DLOCK,#02H ;Setting lock off
setb CH3 ;Dispalying default status as an unlocked
main:
jb IR,main ;Wait for first bit
clr CH1 ;Reseting to indicate Busy
mov CNT,#225 ;Reading the start bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#216
djnz CNT,$
mov c,IR
mov CNT,#225 ;Reading the toggle bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
mov TOG,c
mov EXCNT,#04h ;Reading 4 address bits
mov a,#00h
adloop:
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
djnz EXCNT,adloop
mov CNT,#225 ;Reading 5th address bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#180
djnz CNT,$
mov c,IR
rlc a
mov ADDRS,a ;Storing ADDRESS
mov a,#00h
mov CNT,#225 ;Reading first data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
clr c ; It is always 0 received
rlc a
mov CNT,#225 ;Reading second data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
setb c ;It is always 1 received
rlc a
mov CNT,#225 ;Reading third data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ;Reading forth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ;Reading fifth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CNT,#225 ; Reading sixth data bit
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov CNT,#225
djnz CNT,$
mov CNT,#207
djnz CNT,$
mov c,IR
rlc a
mov CMD,a ;Storing command
mov a,ADDRS ;Validation 1
cjne a,#00h,eop1
mov a,#00h ;Converting both toggles to byte
mov c,OTOG
rlc a
mov TEMP,a
mov c,TOG
mov a,#00h
rlc a
cjne a,TEMP,cont1 ;Validation 2
jmp eop1
cont1:
mov c,TOG
mov OTOG,c
mov TEMP,#00h
mov a,CMD ;Converting command to equivalent decimal count
cjne a,#1Eh,skip1
mov TEMP,#01h
skip1:
cjne a,#1Dh,skip2
mov TEMP,#02h
skip2:
cjne a,#1Ch,skip3
mov TEMP,#03h
skip3:
cjne a,#1Bh,skip4
mov TEMP,#04h
skip4:
cjne a,#1Ah,skip5
mov TEMP,#05h
skip5:
cjne a,#19h,skip6
mov TEMP,#06h
skip6:
cjne a,#18h,skip7
mov TEMP,#07h
skip7:
cjne a,#17h,skip8
mov TEMP,#08h
skip8:
cjne a,#13h,cont2 ;Switching off SWPORT
jmp offall
cont2:
cjne a,#1Fh,cont5 ;Checking for lock signal
jmp checklock
cont5:
mov a,TEMP ;Validation 3
cjne a,#00h,cont3
eop1:
jmp eop
cont3:
mov a,DLOCK ;Validation 4
cjne a,#02h,eop
clr c ;Inverting SWPORT bit as per count
mov a,TEMP
mov CNT,a
mov a,SWPORT
again1:
rrc a
djnz CNT,again1
mov ATEMP,a
mov a,#00h
rlc a
cpl a
rrc a
mov a,TEMP
mov CNT,a
mov a,ATEMP
again2:
rlc a
djnz CNT,again2
mov SWPORT,a
setb CH2 ;SWPORT written indicator
jmp cont4
offall: ;SWPORT off sub module
mov a,#00h
mov SWPORT,a
cont4:
jmp cont6 ;Check lock sub module
checklock:
mov a,DLOCK
cjne a,#02h,incmt
mov DLOCK,#00h
clr CH3
jmp cont7
incmt:
inc DLOCK
cjne a,#01,cont8
setb CH3
cont8:
cont7:
cont6:
eop:
mov EXCNT,#40
loop1:
mov CNT,#255
djnz CNT,$
djnz EXCNT,loop1
setb CH1 ;Seting to indicate as Ready
clr CH2 ;Clearing as default state
ljmp main
end
The code works by sampling data input pin at certain intervals and stores data in registers. After that, according to received data bits, switches are controlled. For example, if '1A' is received, then switch no 5 will be toggled. Similarly, if '17' is received, then switch no 8 will be toggled. Apart form this, if a '0' is pressed once, then it locks the device. If a device is locked, status of switches cannot be changed. For unlocking device, you have to press '0' button twice. After that, it will resume normal operation. Also, when 'STD BY' key of remote is pressed, then all the switches are turned off regardless of their previous state.
This is a very easy to make and fun to use project. You can use it in your house for controlling switches of the switchboard. If you have any problem regarding making this project or want to give Feedback, then post a comment here or mail me at dmehta17@gmail.com.
