MICROCONTROLLER AND ITS INTERFACING WITH IR SENSOR

Microcontroller

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to themicroprocessors used in personal computers or other general purpose applications.

Interfacing 

A microcontroller can be considered a self-contained system with a processor, memory and peripherals and can be used as an embedded system.^[8] The majority of microcontrollers in use today are embedded in other machinery, such as automobiles, telephones, appliances, and peripherals for computer systems.

While some embedded systems are very sophisticated, many have minimal requirements for memory and program length, with no operating system, and low software complexity. Typical input and output devices include switches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency devices, and sensors for data such as temperature, humidity, light level etc. Embedded systems usually have no keyboard, screen, disks, printers, or other recognizable I/O devices of a personal computer, and may lack human interaction devices of any kind.

Interrupts[edit]

Micro controllers must provide real time (predictable, though not necessarily fast) response to events in the embedded system they are controlling. When certain events occur, an interrupt system can signal the processor to suspend processing the current instruction sequence and to begin an interrupt service routine (ISR, or "interrupt handler"). The ISR will perform any processing required based on the source of the interrupt, before returning to the original instruction sequence. Possible interrupt sources are device dependent, and often include events such as an internal timer overflow, completing an analog to digital conversion, a logic level change on an input such as from a button being pressed, and data received on a communication link. Where power consumption is important as in battery operated devices, interrupts may also wake a microcontroller from a low power sleep state where the processor is halted until required to do something by a peripheral event.

The output from the IR sensor circuit will be connected to pins of a PIC18f4550 microcontroller and the microcontroller will regard it as digital input to read either 1 or 0.  According to the output from the IR sensor module, the PIC18F4550 will respond by glowing led. Since we just want to read some voltage in the microcontroller as input (either High or low) hence we are going to configure input pins as digital to read just 1 or 0 from the sensor. - See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpufThe output from the IR sensor circuit will be connected to pins of a PIC18f4550 microcontroller and the microcontroller will regard it as digital input to read either 1 or 0.  According to the output from the IR sensor module, the PIC18F4550 will respond by glowing led. Since we just want to read some voltage in the microcontroller as input (either High or low) hence we are going to configure input pins as digital to read just 1 or 0 from the sensor. - See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpufThe output from the IR sensor circuit will be connected to pins of a PIC18f4550 microcontroller and the microcontroller will regard it as digital input to read either 1 or 0.  According to the output from the IR sensor module, the PIC18F4550 will respond by glowing led. Since we just want to read some voltage in the microcontroller as input (either High or low) hence we are going to configure input pins as digital to read just 1 or 0 from the sensor. - See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpufThe output from the IR sensor circuit will be connected to pins of a PIC18f4550 microcontroller and the microcontroller will regard it as digital input to read either 1 or 0.  According to the output from the IR sensor module, the PIC18F4550 will respond by glowing led. Since we just want to read some voltage in the microcontroller as input (either High or low) hence we are going to configure input pins as digital to read just 1 or 0 from the sensor. - See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpuf

The output from the IR sensor circuit will be connected to pins of a PIC18f4550 microcontroller and the microcontroller will regard it as digital input to read either 1 or 0.  According to the output from the IR sensor module, the PIC18F4550 will respond by glowing led. Since we just want to read some voltage in the microcontroller as input (either High or low) hence we are going to configure input pins as digital to read just 1 or 0 from the sensor. - See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpuf

The output from the IR sensor circuit is connected to RA0 of the pic18f4550 which is configured as input with TRISB registers, and the output will be displayed on LED connected across RD7, RD6,RD5 (PORTD) and RB0 and RB1 (PORTB) which are configured as output pins. Follow the schematic below.

Schematic (IR sensor and PIC18F4550 microcontroller)

In this project we don’t need to perform any Analog to Digital Conversion(ADC), hence we are going to turn the ADC off (ADCON0bits.ADON = 0) and configure all the PINS to Digital.  At the default 1 MHZ oscillator frequency the output sometimes gives unstable result, hence tuning the microcontroller to 8MHZ solved the problem, Please note that pic18f4550 works by default on 1 MHZ and you can change the OSCCON bits settings to tune the oscillator frequency according to your requirement.

Search in pic18f4550 datasheet for OSCCON register bits and you will find a nice description and bits settings table for available oscillator frequency and settings to configure the microcontroller oscillator frequency. Here I have configured the internal oscillator to 8MHZ to avoid switch debouncing. However it works well with 1MHZ settings as well. As a better plan the comparator is also turned off to avoid any conflict.

                          All the resistors in the above Schematic is 1k resistance. If possible, it is also recommended to add a IC 7805 liner Voltage regulator IC as a source of +5V to avoid any voltage fluctuation which could possibly damage the microcontroller. Make sure the input voltage to pic18f4550 must never exceed +5v. Please do read the excellent pic18f4550 datasheet provided by microchip.

Source Code:

MPLAB IDE and C18 Compiler is used for compiling the source code, however MPLAB X IDE and XC8 Compiler can be also used with no difficulty. Download the entire project at the end of the source code below with compiled firmware. 

SOURCE CODE :infraredinput.c

/*
 * File:   infraredinput.c
* Author: ron
 * December 10, 2012, 1:21 PM
 */
#include <p18f4550.h>           // Include Header for PIC18F4550
#define switch1  PORTAbits.RA0  // Switch on RA0
#define led1    LATDbits.LATD7     // led1
#define led2    LATDbits.LATD6    // led2
#define led3    LATBbits.LATB0   // led3
#define led4    LATBbits.LATB1    // led4
#define led5    LATBbits.LATB2    // led5
void main (void)
{
            /* If you want your microcontroller to work at  1MHZ then comment the three lines below */
OSCCONbits.IRCF0 = 1 ;               // set internal clock to 8 MHz
OSCCONbits.IRCF1 = 1;                //  For Avoiding switch debouncing problem     
OSCCONbits.IRCF2= 1;                 //
/* Input output settings*/
       TRISAbits.TRISA0 = 1;                  //   RA0 Input for taking input from IR sensor
       TRISDbits.TRISD7 = 0;                  // Port D pins output
       TRISDbits.TRISD6 = 0;
       TRISBbits.TRISB0 = 0;                  // Port B pins Output
       TRISBbits.TRISB1 = 0;
       TRISBbits.TRISB2 = 0;
       CMCON = 0x07;           // Disable Comparator
       ADCON1bits.PCFG0 = 1;          // These 4 settings below determines the analog or digital input
       ADCON1bits.PCFG1 = 1;          // In our case we are making all the pins digital
       ADCON1bits.PCFG2 = 1;         // by setting them as 1111
       ADCON1bits.PCFG3 = 1;         // Check with the datasheet for a nice desc of these bits and config.
       ADCON0bits.ADON = 0;  //  Disabled ADC
while(1)
     {   //Forever Loop
            if(switch1 == 1)    //   On reading IR sensor value ON
                    {    //Turn led ON
                                led1 = 1;
                                 led2 = 1;
                              led3 = 1;
                              led4 = 1;
                                 led5 = 1;              }
       else if ( switch1 == 0) // On reading IR Sensor Value OFF
                      {   //Turn led off
                              led1 = 0;
                            led2 = 0;
                            led3 = 0;
                            led4 = 0;
                            led5 = 0;              }
                                     else {    }
    }   //End While loop --forever
}
/* THE END */

The coding above is pretty much self-explanatory, and comment lines must be also helpful for better understanding.

- See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpuf

The output from the IR sensor circuit is connected to RA0 of the pic18f4550 which is configured as input with TRISB registers, and the output will be displayed on LED connected across RD7, RD6,RD5 (PORTD) and RB0 and RB1 (PORTB) which are configured as output pins. Follow the schematic below.

Schematic (IR sensor and PIC18F4550 microcontroller)

In this project we don’t need to perform any Analog to Digital Conversion(ADC), hence we are going to turn the ADC off (ADCON0bits.ADON = 0) and configure all the PINS to Digital.  At the default 1 MHZ oscillator frequency the output sometimes gives unstable result, hence tuning the microcontroller to 8MHZ solved the problem, Please note that pic18f4550 works by default on 1 MHZ and you can change the OSCCON bits settings to tune the oscillator frequency according to your requirement.

Search in pic18f4550 datasheet for OSCCON register bits and you will find a nice description and bits settings table for available oscillator frequency and settings to configure the microcontroller oscillator frequency. Here I have configured the internal oscillator to 8MHZ to avoid switch debouncing. However it works well with 1MHZ settings as well. As a better plan the comparator is also turned off to avoid any conflict.

                          All the resistors in the above Schematic is 1k resistance. If possible, it is also recommended to add a IC 7805 liner Voltage regulator IC as a source of +5V to avoid any voltage fluctuation which could possibly damage the microcontroller. Make sure the input voltage to pic18f4550 must never exceed +5v. Please do read the excellent pic18f4550 datasheet provided by microchip.

Source Code:

MPLAB IDE and C18 Compiler is used for compiling the source code, however MPLAB X IDE and XC8 Compiler can be also used with no difficulty. Download the entire project at the end of the source code below with compiled firmware. 

SOURCE CODE :infraredinput.c

/*
 * File:   infraredinput.c
* Author: ron
 * December 10, 2012, 1:21 PM
 */
#include <p18f4550.h>           // Include Header for PIC18F4550
#define switch1  PORTAbits.RA0  // Switch on RA0
#define led1    LATDbits.LATD7     // led1
#define led2    LATDbits.LATD6    // led2
#define led3    LATBbits.LATB0   // led3
#define led4    LATBbits.LATB1    // led4
#define led5    LATBbits.LATB2    // led5
void main (void)
{
            /* If you want your microcontroller to work at  1MHZ then comment the three lines below */
OSCCONbits.IRCF0 = 1 ;               // set internal clock to 8 MHz
OSCCONbits.IRCF1 = 1;                //  For Avoiding switch debouncing problem     
OSCCONbits.IRCF2= 1;                 //
/* Input output settings*/
       TRISAbits.TRISA0 = 1;                  //   RA0 Input for taking input from IR sensor
       TRISDbits.TRISD7 = 0;                  // Port D pins output
       TRISDbits.TRISD6 = 0;
       TRISBbits.TRISB0 = 0;                  // Port B pins Output
       TRISBbits.TRISB1 = 0;
       TRISBbits.TRISB2 = 0;
       CMCON = 0x07;           // Disable Comparator
       ADCON1bits.PCFG0 = 1;          // These 4 settings below determines the analog or digital input
       ADCON1bits.PCFG1 = 1;          // In our case we are making all the pins digital
       ADCON1bits.PCFG2 = 1;         // by setting them as 1111
       ADCON1bits.PCFG3 = 1;         // Check with the datasheet for a nice desc of these bits and config.
       ADCON0bits.ADON = 0;  //  Disabled ADC
while(1)
     {   //Forever Loop
            if(switch1 == 1)    //   On reading IR sensor value ON
                    {    //Turn led ON
                                led1 = 1;
                                 led2 = 1;
                              led3 = 1;
                              led4 = 1;
                                 led5 = 1;              }
       else if ( switch1 == 0) // On reading IR Sensor Value OFF
                      {   //Turn led off
                              led1 = 0;
                            led2 = 0;
                            led3 = 0;
                            led4 = 0;
                            led5 = 0;              }
                                     else {    }
    }   //End While loop --forever
}
/* THE END */

The coding above is pretty much self-explanatory, and comment lines must be also helpful for better understanding.

- See more at: http://www.rakeshmondal.info/IR-Sensor-Interface-pic18f4550-input#sthash.gt45TPe7.dpuf