HC-SR04 sensor triggering sound through DFPlayer – circuit issues

[marteteigen]

Hi!

I'm trying to trigger an MP3 file through a DFPlayer based on the distance measured by a HC-SR04 sensor. I can get them both to work individually, but when I try to rewire so that their both connected to the Arduino Uno I run into problems. I'm guessing the wiring / circuit is the issue.

When I connect the cables to 5V and GND the Arduino seems to shut down. When I try to upload code I get the error: "stk500 programmer is not responding". No errors when verifying the code. When I disconnect the 5V and GND the Arduino works, and I can upload code to it (tested the Examples > Basic > Blink code).

Here's my current wiring:

The Arduino Uno is so far just powered through my laptop. Is 5V sufficient for this? I've also considered using a breadboard power supply, and power the Ardunio through that, but this is pretty new to me. Here's my sketch, but I haven't tried it out yet:

And here's my code, that I haven't really tried out yet, because I can't upload it. For the DFPlayer I've used the same setup as this tutorial.

#include "./lib/mp3tf16p.h"

#define led 13

// MP3 Player
MP3Player mp3(10, 11);

const int trigPin = 6;
const int echoPin = 2; 

long duration; 
int distance;  
bool isPlaying = false; // Flag to track playback state

void setup(void)
{
  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT); 

  Serial.begin(9600);
  pinMode(led, OUTPUT);
  mp3.initialize();

  Serial.println("MP3 Player initialized.");
}

void loop(void)
{
  mp3.serialPrintStatus(MP3_ALL_MESSAGE);
  delay(100);

  // Trigger the HC-SR04 sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the duration of the echo pulse
  duration = pulseIn(echoPin, HIGH);

  // Convert duration to distance in cm
  distance = duration * 0.034 / 2; 

  Serial.print("Distance: ");
  Serial.println(distance);
  
  delay(500); // Adjust delay if needed

  // If the distance is less than 10 cm and not already playing, start playing
  if (distance < 10 && !isPlaying) {
    Serial.println("Object detected! Playing sound...");
    mp3.playTrackNumber(1, 30, false);
    isPlaying = true;  // Set flag to prevent repeated playback
  } 
  // If the distance is greater than or equal to 10 cm and was playing, stop playback
  else if (distance >= 10 && isPlaying) {
    Serial.println("Object moved away. Stopping playback.");
    mp3.stop();
    isPlaying = false;  // Reset flag
  }
}

Any input is very much appreciated!

[ruilviana]

Think about:
Arduino UNO is a power supply?
No.
Use a external power suplly to HC-SR and sound modules.
Don't forget, connect all GND together.

[marteteigen]

Thanks for your answer. Would something like this work?

[gilshultz]

@marteteigen

Is 5V sufficient for this?

That is a Yes/No answer. 5 Volts should be fine but the Arduino cannot supply the needed current, causing it to fold back (lower voltage to control current). As suggested by @ruilviana use an external power supply for the Audio portion.

[marteteigen]

Thanks for the input! I get that I need an external power supply, but I'm still a bit uncertain about the wiring, and spesifically how to make sure that everything has a common ground.

Here's an example using both power rails on the breadboard, with a breadboard power supply:

The Arduino is connected to the minus rail on both sides.

Here's an example using a 9V battery in one of the rails:

Would both of these work? Is one solution better than the other?

[ruilviana]

Caution. Vin does not have reverse polarity protection.

[gilshultz]

Spend some time and go through the Arduino Cookbook, it probably has your project in it. Sorry I do not follow fritzing very well. As in your case it is not labeled very well and I do not have the parts you used as a reference.