Arduino我如何存储最后的IR代码以检查是否需要重复？

Question

I'm just learning Arduino and i've got a DC Motor & IR Receiver connected. It's working fine if i press the button once but i can't figure out how to keep the motor spinning if i hold the button down as the REPEAT command is the same numbers.

I figured i would store the last code sent and check if the repeat command and last code match but it doesn't seem to be working and can't figure out why.

#include <IRremote.h>

int IRpin = 11;  // pin for the IR sensor
IRrecv irrecv(IRpin);
decode_results results;
int lastCode;

void setup() {
  // put your setup code here, to run once:
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(13, OUTPUT);
  Serial.begin(9600);
  irrecv.enableIRIn(); // Enable IR Receiver.
}

void loop() {
  // put your main code here, to run repeatedly:


if

 (irrecv.decode(&results)) {
  Serial.println(results.value);
  irrecv.resume(); 
  Serial.println("Last Code is set to: ");
  Serial.write(lastCode);


  if(results.value== 16748655 || (results.value== 4294967295 && lastCode== 16748655)) // Your ON button value                                       
  {
      digitalWrite(8, HIGH);
      digitalWrite(7, LOW);
      analogWrite(9, 255);
      delay(1000);
      analogWrite(9, 0);
      lastCode= 16748655;

  }


  else if(results.value == 16769055 || (results.value== 4294967295 && lastCode== 16769055)) // Your OFF button value 
  {
      digitalWrite(8, LOW);
      digitalWrite(7, HIGH);
      analogWrite(9, 255);
      delay(1000);
      analogWrite(9, 0);
      lastCode= 16769055;

  }
}


}

Answer 1

A more reliable approach to running the motor until the button is released is to use a "no-code" timeout. That is, if the "no code" state persists for a period longer than the auto-repeat period, then it has been released.

It is not clear in your code what the 1 second analogue pulse is for, but placing long delays in your loop() function makes your system far less responsive. Better to poll the system tick and "do stuff" when it is time to do so. Also magic numbers should be avoided if you want anyone to understand your code and avoid errors in maintenance.

The following uses system tick polling to implement the "no-code" timeout. I have omitted the motor on/off code because it is not clear what you are doing there with the 1 second delays.

#define NO_CODE        0xFFFFFFFFul
#define MOTOR_ON_CODE  0xFF906Ful
#define MOTOR_OFF_CODE 0xFFE01Ful
#define STOP_TIME_MS   250ul  // stop after button release for 250ms

void loop( )
{
    static unsigned long last_on_time = 0 ; 

    if( irrecv.decode( &results ) )
    {
        irrecv.resume() ;

        unsigned long code = results.value ;

        // If motor off code or no code timeout...
        if( code == MOTOR_OFF_CODE ||
            (code == NO_CODE && millis() - last_on_time > STOP_TIME_MS) )
        {
            // Motor off
            ...
        }
        else if( code == MOTOR_ON_CODE )
        {
            // Continuously update last on time while button is held
            last_on_time = millis() ;

            // Motor on
            ...
        }
    }
}

I have included response to the motor-off code, but that may not be necessary, since the motor will be switched off 250ms (or whatever time you choose) after the ON button is released in any case. You might instead have a forward/reverse button and release either to stop:

#define NO_CODE        0xFFFFFFFFul
#define MOTOR_FWD_CODE 0xFF906Ful
#define MOTOR_REV_CODE 0xFFE01Ful
#define STOP_TIME_MS   250ul  // stop after button release for 250ms

void loop( )
{
    static unsigned long last_on_time = 0 ; 

    if( irrecv.decode( &results ) )
    {
        irrecv.resume() ;

        unsigned long code = results.value ;
        switch( code )
        {
            case NO_CODE :
            {
                if( millis() - last_on_time > STOP_TIME_MS )
                {
                    // Motor off
                    ...          
                }
            }
            break ;

            case MOTOR_FWD_CODE :
            {
                // Continuously update last on time while button is held
                last_on_time = millis() ;

                // Motor forward
                ...
            }
            break ;

            case MOTOR_FWD_CODE :
            {
                // Continuously update last on time while button is held
                last_on_time = millis() ;

                // Motor reverse
                ...
            }
            break ;
        }
    }
}