Two DC motors control from IR remote control – CCS C

After controlling 2 DC motors speed and direction of rotation with 2 potentiometers, now let’s make the same project but with IR remote control. First project is at the link below:
Two motors control using PIC16F887 and L293D

The microcontroller used in this project is PIC16F887 and the remote control is Car MP3 IR remote control which uses NEC protocol. Decoding of this remote control with PIC16F887 is done in the following project:
NEC Protocol decoder with PIC16F887 microcontroller

In this project 6 buttons are used for controlling the speed and rotation direction of the 2 motors, these buttons are shown in the following image:

Car MP3 NEC protocol button codes

The code of each button are as shown in the following table (these codes will be used later in the C code):

Button Number
Motor 1 Start/Toggle direction
Motor 1 speed down
Motor 1 speed up
Motor 2 Start/Toggle direction
Motor 2 speed down
Motor 2 speed up

Hardware Required:

  • PIC16F887 microcontroller
  • 2 x DC motor (I used 12V motors)
  • L293D motor driver
  • NEC IR remote control (I’m using Car MP3 as the one above)
  • IR receiver
  • 10K ohm resistor
  • 47µF capacitor
  • 5V and 12V voltage sources
  • Breadboard
  • Jumper wires

Two DC motors control with NEC IR remote control and PIC16F887 circuit:

DC motor remote control circuit

As shown in the circuit diagram the IR receiver output is connected to RB0 pin which is external interrupt pin of the PIC16F887 microcontroller.
The L293D IC is used to drive both motors in the two directions, the speed of the two motors is controlled the two PWM signals which come from the microcontroller. PWM1 controls motor 1 speed and PWM2 controls motor 2 speed. Motor 1 direction is controlled with IN1 and IN2 pins of the L293D, these pins are connected to RD0 and RD1 of the PIC16F887. Motor 2 is controlled with pin IN3 and IN4 of the L293D, IN3 is connected to RD2 and IN4 is connected to RD3 of the microcontroller. When IN1 = IN2 = 0, motor 1 stops, when IN1 = 1 and IN2 = 0 motor 1 moves in the first direction, when IN1 = 0 and IN2 = 1 motor 1 moves in the second direction. The same thing for motor 2 with pins IN3 and IN4.
The 10K ohm resistor is used to minimize the IR receiver output noise.
In the circuit there are two voltage sources, one with 5V which supplies most of the circuit and the other one with 12V which supplies only the L293D IC. The 12V source depends on the motors nominal voltage.
In this project the PIC16F887 uses its internal oscillator and MCLR pin function is disabled.

Two DC motors control with NEC IR remote control CCS C code:
Project C code is as shown below. It has been tested with CCS PIC C compiler version 5.051.
PIC16F887 hardware external interrupt and Timer1 are used to decode the IR remote control. Timer1 is used to measure pulses and spaces widths and its interrupt (Timer1 interrupt) is used to reset the decoding process in case of very long pulse or space (time out). Timer1 is configured to increment every 1µs using the following command line:
setup_timer_1( T1_INTERNAL | T1_DIV_BY_2 );
But Timer1 module will not start until the microcontroller receives an interrupt on pin RB0 (interrupt edge from high to low).
The motor speed changes whenever the duty cycle of the PWM signal changes, and thus if the microcontroller receives speed up button code it will increment the duty cycle, then motor speed will be increased, and if the microcontroller receives speed down button code, the duty cycle will be decreased which causes the motor to decrease its speed.

At start up , both motors are stopped because all PORTD pins are zeroes with the command output_d(0); and when start/toggle direction button is pressed, the motor will start (if there is sufficient duty cycle otherwise the duty cycle have to be increased), and the same button pressed again the motor will change its direction of rotation.
The full C code is shown below.

The following video shows a hardware circuit of our project:

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