Introduction: TV Remote Controlled Home Appliance Using 8051

This project is used to switch the electrical appliances remotely using TV remote. It uses philips RC5 protocol based remote. The micro controller used is of Atmel i.e. at89c2051 of 8051 type. I have used triacs instead of relays to switch the AC appliance due to the reason of switching speed of circuit.

Step 1: Parts Needed

  • Dotted PCB
  • 12-0-12 step down transformer
  • 1N4007 diode
  • LM7805 5V voltage regulator
  • 1000uf electrolytic capacitor
  • at89c2051 microcontroller
  • 20dip IC base
  • 11.0592 MHz crystal
  • debounce switch
  • 10uf electrolytic capacitor
  • 33pf ceramic capacitor
  • 8.2k resistor
  • red leds
  • 1738/1838T/2238 IR receiver modules ( Use any of these, just check the pins carefully )
  • BC547 NPN transistor
  • BT136 triacs
  • soldering iron
  • soldering wire
  • 1K resistors
  • RC5 protocol TV remote
  • 8051 programmer
  • some wires and jumpers

Step 2: Circuit Diagram

Here is the complete circuit diagram for project. I have also added eagle schematic file.

Step 3: Working on Dotted PCB

Place all the components on dotted PCB according to circuit diagram. Steps shown in images.

Step 4: Assembly Code for 8051 Microcontroller

Compile this asm file using any 8051 assembler program. I have used this ASEM-51 assebler. It creates .hex file, which we need to upload to the microcontroller using 8051 programmer. I have used "Top win Universal Programmer" . Check it here Top win Products. It can be interfaced with so many microcontrollers,eeproms etc.

; ; ; TV Remote based home appliance switching system. ; ; Jaspal Singh ; ; 05/06/2015 ; ; ; ; ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; $mod51

VAR1 equ r7 ;Temporary Variable TEMP equ 10H ;Temp variable COUNT equ 11H ;Count ADDR equ 12H ;Device address CMD equ 13H ;Command FLIP bit 00H ;Flip bit TOG bit 01H ;Temp bit for flip IR equ P3.3 ;IR Receiver connected to this pin SW1 equ P1.0 ;Switch 1 connected here SW2 equ P1.1 ;Switch 2 connected here SW3 equ P1.2 ;Switch 3 connected here SW4 equ P1.3 ;Switch 4 connected here SW5 equ P1.4 ;Switch 5 connected here SW6 equ P1.5 ;Switch 6 connected here SW7 equ P1.6 ;Switch 7 connected here SW8 equ P1.7 ;Switch 8 connected here SWport equ P1 ;Port at which switches are connected org 00H ;Start of prog mov SWport,#00H ;switch all relays off! mov sp,#50H ;Stack pointer initialization clr TOG ;Clear temp bit main: jb IR,$ ;Wait for first bit mov VAR1,#255 ;3.024mS delay djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#100 djnz VAR1,$ mov c,IR ;Read Flip bit mov FLIP,c clr A mov COUNT,#5 ;Count for address fadd: mov VAR1,#255 ;1.728mS delay for each bit djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#4 djnz VAR1,$ mov c,IR rlc a djnz COUNT,fadd mov ADDR,A ;Save the address clr a mov COUNT,#6 ;Count for Command fcmd: mov VAR1,#255 ;1.728mS Delay for each bit djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#255 djnz VAR1,$ mov VAR1,#4 djnz VAR1,$ mov c,IR rlc a djnz COUNT,fcmd mov TEMP,CMD ;Save the old command mov CMD,a ;Save the new command mov a,ADDR ;Cheack for valid address cjne a,#00,nvalid mov a,TEMP cjne a,CMD,valid ;Check for valid command nvalid: ljmp main valid: ;Key press check clr a mov c,FLIP rlc a mov TEMP,a clr a mov c,TOG rlc a cjne a,TEMP,valid1 sjmp nvalid valid1: mov c,FLIP mov TOG,c mov a,CMD clr c cjne a,#1,skip1 ;Check for SW1 jb SW1,isset1 setb SW1 ljmp main isset1: clr SW1 ljmp main skip1: cjne a,#2,skip2 ;Check for SW2 jb SW2,isset2 setb SW2 ljmp main isset2: clr SW2 ljmp main skip2: cjne a,#3,skip3 ;Check for SW3 jb SW3,isset3 setb SW3 ljmp main isset3: clr SW3 ljmp main skip3: cjne a,#4,skip4 ;Check for SW4 jb SW4,isset4 setb SW4 ljmp main isset4: clr SW4 ljmp main skip4: cjne a,#5,skip5 ;Check for SW5 jb SW5,isset5 setb SW5 ljmp main isset5: clr SW5 ljmp main skip5: cjne a,#6,skip6 ;Check for SW6 jb SW6,isset6 setb SW6 ljmp main isset6: clr SW6 ljmp main skip6: cjne a,#7,skip7 ;Check for SW7 jb SW7,isset7 setb SW7 ljmp main isset7: clr SW7 ljmp main skip7: cjne a,#8,skip8 ;Check for SW8 jb SW8,isset8 setb SW8 ljmp main isset8: clr SW8 ljmp main skip8: cjne a,#0CH,exit ;Check for all switches mov SWport,#00H ljmp main exit: ljmp main

END ;End of program

Step 5: Final Touch

I have given some final touch to the project using some chart paper and marker.