Playing specific audio files from DFPlayer Mini without serial connection

Other Hardware Audio
1

Hi community,

In my current project I'm using an Arduino BLE Sense 33 together with the picovoice porcupine wakeword engine, which is working great. However I want to be able to play prerecorded audio files (minimum 2) after a wakeword got recognized by the arduino.

I've got a DFPlayer mini here which would work perfectly for this I guess. The only problem I have is that the Serial ports RX and TX are already in use by an ESP8266 (ESP01 in specific) to get the Arduino WiFi capabilities.

Question: Can it still be done to control the DFPlayer with serial in parallel to the ESP Wifi breakout?

If not I figured that the DFPlayer can also be played by grounding specific pins for a short time.
If I ground the Pin ADKEY_1 manually by a jumper cable the first file 0001.mp3 plays, if I ground the ADKEY_2 pin, the second plays. But if I try to replicated this by the Arduino by


digitalWrite(10, LOW);
delay(500);
digitalWrite(10, HIGH);
delay(1000);
digitalWrite(11, LOW);
delay(500);
digitalWrite(11, HIGH);

one file can be played, but keeps on looping or the second one can't be played.

What would be the best solution for my issue?

Thanks for your thoughts!

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image1404×938 115 KB

2

Use software serial.

But first check if your arduino has other, spare hardware serial (UART) ports.

3

Software Serial is already in use for the ESP AT commands. Or do I understand something wrong here? This is what the library WifiESPAT uses:
SoftwareSerial Serial1(6, 7); // RX, TX

4

Then use the hardware serial port for the MP3 module!

If I were you, I would use the hardware serial port for the esp and software serial for the MP3.

5

Taken from the Arduino docs, there is no real SoftwareSerial on the BLE 33 Sense:

The USB connector of the board is directly connected to the native USB of the NINA B306 module. This routing enables you to use the Arduino Nano 33 BLE Sense as a client USB peripheral (acting as a mouse or a keyboard connected to the computer) or as a USB host device so that devices like a mouse, keyboard, or an Android phone can be connected to the Arduino Nano 33 BLE. This port can also be used as a virtual serial port using the Serial object in the Arduino programming language. The RX0 and TX1 pins are a second serial port available as Serial1.

I think I can't use other pins as serial ports, right? I'm already using Serial1 for the ESP

6

That's crazy! Serial1 is the hardware serial port on ble 33. That code overrides it, making it an inferior software serial port.

Can you connect the esp to the hardware serial port and change that code to Serial2 for use with the MP3 module?

7

I see nothing in the text you quoted that says you can't use software serial. And, anyway, didn't you say in your last post that you are using software serial (on pins 6,7) already for the esp?

I think you have already proved that you can, by using software serial on pins 6, 7!

8

Sorry, my mistake. In the code the line is wrapped by an if / else:

// Emulate Serial1 on pins 6/7 if not present
#if defined(ARDUINO_ARCH_AVR) && !defined(HAVE_HWSERIAL1)
#include <SoftwareSerial.h>
SoftwareSerial Serial1(6, 7); // RX, TX
#define AT_BAUD_RATE 9600
#else
#define AT_BAUD_RATE 115200
#endif

Furthermore Serial1 is used to speak to TX and RX ports.

The softwareSerial library seems to not exist on the BLE 33 sense: Arduino 33 BLE Sense – libraries compatybility

1 Like
9

Found this one in the meantime: [Feature Request] Add SoftwareSerial / Uart lib to Nano 33 · Issue #38 · arduino/ArduinoCore-nRF528x-mbedos · GitHub

could possibly solve my problems. Will let you know.

10

Well done, that sounds very easy!

So you may just need to add

UART Serial2(digitalPinToPinName(6), digitalPinToPinName(7), NC, NC);
11

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