Using MP3-TF-16P with 4ohm, 3W speaker

Projects General Guidance
1

I am using MP3-TF-16P with Arduino mega and a 3W, 4ohm GIKFUN speaker without any amplifiers. I connected the six pins of MP3 to the mega and the speaker as required including the RX pin with a 1K resistor in series. I have tried both the hardware serial and the software serial methods. In both cases, the MP3 passes all the required tests, and it lights up as if it is playing the file from the micro-SD card, but no sound comes out of the speaker. Trying different speakers (3W, 4ohm and 2W, 8ohm) didn’t help. All the wires are checked for continuity. In fact, while the program is running, I measured the voltage across the speaker and it did change, but again no sound. I am using a very simple sketch shown below. Any help will be greatly appreciated.

I am using MP3-TF-16P with Arduino mega and a 3W, 4ohm GIKFUN speaker without any amplifiers. I connected the six pins of MP3 to the mega and the speaker as required including the RX pin with a 1K resistor in series. I have tried both the hardware serial and the software serial methods. In both cases, the MP3 passes all the required tests, and it lights up as if it is playing the file from the micro-SD card, but no sound comes out of the speaker. Trying different speakers (3W, 4ohm and 2W, 8ohm) didn’t help. All the wires are checked for continuity. In fact, while the program is running, I measured the voltage across the speaker and it did change, but again no sound. I am using a very simple sketch shown below. Any help will be greatly appreciated.
#include <SoftwareSerial.h>
#include <DFRobotDFPlayerMini.h>
//#include "mp3tf16p.h"
SoftwareSerial mySoftwareSerial(10, 11);
DFRobotDFPlayerMini myDFPLayer;
void setup() {
  mySoftwareSerial.begin(9600);
  myDFPLayer.begin(mySoftwareSerial);
  myDFPLayer.volume(20);
  myDFPLayer.loopFolder(1);
}
void loop() {
}
2

Please post the wiring diagram. A separate power supply, capable of supplying at least 1 Ampere is required the player.

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3

Double check your connections to the speaker. Try another speaker.

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4

Welcome!
I have an idea but I will wait until the annotated schematic is posted along with links to technical information on the hardware devices.

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5

@mads_projects

Almost certainly a wiring or hw error because your sketch works fine here on a Uno R3.

I used the USB supply, but my volume was 5 not 20 to avoid waking my wife, so current not an issue.
:slightly_smiling_face:

6

I am still trying to learn the software to draw the wiring diagram, but I am quite certain it is not the wiring diagram because there are only six connections which I have strictly followed. In any case, I will try to post the wiring diagram by tomorrow. Thanks for your reply.

7

Pencil and paper work extremely well, and would be much faster than learning how to use a drawing program. Post a pic of your artwork.

8

I have already tried three different speakers and four different GIKFUN MP3 modules with no success. Thanks for your suggestion.

9

If the Busy LED is coming on and you're seeing voltage changes across the speaker pins, then the problem is most likely in either the wiring to the speaker or the speaker itself. The module is apparently working. It's playing a track, and the output is making it to the speaker pins. The only things left after that are the speaker wires or speaker.

You almost certainly have a hardware problem, and yet you haven't shown us anything hardware related.

10

AudioSchematic.pdf (57.4 KB)

11

I have just uploaded the schematic. Can you please look at it? Thanks.

12

Unfortunately, the schematic is not complete and doesn't show ground connections to the external power supply.

Perhaps you forgot to connect all the grounds, as required.

13

Sorry, I didn't show all the ground connections, but all the ground connections were connected to Arduino ground.

14

That should work. Use your multimeter to check connectivity of all connections, and voltages at various places in the circuit.

It could be that you have a defective player board.

15

Using the multimeter, I have checked the connectivity of all wires, the supply voltage is 5V (checked). You are perhaps right the MP3 board may be at fault. I had three MP3 boards from the same supplier. I tried all three of them with the same result. I just ordered a DFPlayer from DFRobot. When it arrives, I will know if the MP3 board was the culprit. Thanks for your suggestions.

16

Have you tested the player boards by connecting ADKEY1 to ground? That should trigger playing track 1.

If that doesn't work, no point worrying about the Arduino or it's code.

Also try a different SD card.

17

In the simple sketch that I am using for testing purpose is already asking to play track 1. I just tried grounding the ADKEY1 - it made no difference. I have also used a different SD card formatted in FAT32 format - this also did not help. Thanks for your suggestion.

18

Did the blue "busy" led come on?

19

Yes, it did

20

You are certain none of the audio files on the card are blank/silence?

Can you connect a powered speaker to the DAC_L and/or DAC_R pins?