Playing soundbite with servo movement

Projects General Guidance
1

I am trying to make a Halloween decoration, it is a skeleton that lifts the right arm when someone walks through the door and plays a sound.

Basically:

  • Photoresistor and laser pointer to set up a makeshift trip sensor
  • Servo moves the arm up and down when the laser is interrupted
  • Sound plays when the laser is interrupted

So far, I have the laser sensor and arm movement working fine, when I interrupt the laser path the arm moves up and down. However when I try to integrate the speaker code, the servo does not move.

I have narrowed down the issue to the line that actually calls for the sound to be played:
"tmrpcm.play("WFM.wav");"

When I remove that line the servo moves as expected, but adding that line prevents the servo from moving. It does not matter if the speaker/SD are connected to the circuit.

The SD card code is something I found online, I have used it successfully on other projects but never when calling it from an if statement.

I'm guessing I have the line in question in the wrong place, but I'm not sure.

Here is the code:


#include <Servo.h>

#include <SD.h> // need to include the SD library
#define SD_ChipSelectPin 4 //connect pin 4 of arduino to cs pin of sd card
#include <TMRpcm.h> //Arduino library for asynchronous playback of PCM/WAV files
#include <SPI.h> 

Servo myservo; 

 TMRpcm tmrpcm; 
int temp=1;

int pos = 0;    
int UpPos = 140;
int DownPos = 10;
int MidPos = 70;

int PhotoThresh = 600;
int PhotoLevel = 0;

int CycleCount = 0;

void setup() {
  myservo.attach(7); 

 tmrpcm.speakerPin = 9; //5,6,11 or 46 on Mega, 9 on Uno, Nano, etc
 Serial.begin(9600);
 if (!SD.begin(SD_ChipSelectPin)) // returns 1 if the card is present
 {
  Serial.println("SD fail");
  return;
 }

  Serial.begin(9600);

  tmrpcm.setVolume(5);
}

void loop() {

  int PhotoLevel = analogRead(A0);
  Serial.print("PhotoLevel: ");
  Serial.println(PhotoLevel);

  if(PhotoLevel < PhotoThresh){  //Trigger if laser is not hitting the photoresistor

  Serial.println("Start Move");

  tmrpcm.play("WFM.wav"); //This line prevents the servo from moving, intended to play WFM.wav from SD card

 Serial.println("Play Song");
    
  for (pos = DownPos; pos <= UpPos; pos += 1) { 
    myservo.write(pos);  
    Serial.println(pos);
    delay(15); 
    
  }

  Serial.print("UpPos ");
  Serial.println(pos);
  
  for (pos = UpPos; pos >= MidPos; pos -= 1) { 
    myservo.write(pos); 
    Serial.println(pos);
    delay(15);   
  }

  Serial.print("MidPos ");
  Serial.println(pos);

  
   for (pos = MidPos; pos <= UpPos; pos += 1) { 
    // in steps of 1 degree
    myservo.write(pos);  
    Serial.println(pos);
    delay(15); 
  }

  Serial.print("UpPos ");
  Serial.println(pos);

    for (pos = UpPos; pos >= MidPos; pos -= 1) { 
    myservo.write(pos); 
    Serial.println(pos);
    delay(15);   
  }

  Serial.print("MidPos ");
  Serial.println(pos);

  
   for (pos = MidPos; pos <= UpPos; pos += 1) { 
    myservo.write(pos);  
    Serial.println(pos);
    delay(15); 
   }

  Serial.print("UpPos ");
  Serial.println(pos);

  for (pos = UpPos; pos >= DownPos; pos -= 1) { 
    myservo.write(pos); 
    Serial.println(pos);
    delay(15);   
  }

  Serial.print("DownPos ");
  Serial.println(pos);

  CycleCount = CycleCount + 1;
  Serial.print("Cycle count ");
  Serial.println(CycleCount);
  delay(1000);
  }


  
}
2

TMRpcm and the servo library are probably trying to use the same timer (Timer1).

If you have an Uno, Nano, Mega or similar, try the ServoTimer2 library.

3

That was the problem, thanks!

4

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