Issue with Ground Connection Causing DFPlayer Mini to Short Out
Hi everyone,
I'm working on a project using an ESP32, an L298N motor driver, and a DFPlayer Mini, and I've encountered an issue when connecting a specific ground wire. Below are my connections:
Connections Overview
ESP32 (Powered via USB-C)
- GPIO 25, 33 → IN1, IN2 (L298N driver)
- GPIO 16, 17 → TX, RX (DFPlayer Mini) (GPIO 16 to DFPlayer TX)
- GPIO 4 → Hang-Up Point on Phone (Found via a YouTube video showing detection of the mechanism)
- VIN → VCC (DFPlayer Mini)
- Ground → Ground (DFPlayer Mini)
DFPlayer Mini
(Excluding connections already mentioned to ESP32)
- SPK1 → Green Wire (Headphone Jack on Phone)
- SPK2 → Red Wire (Headphone Jack on Phone)
L298N Motor Driver
(Excluding connections already mentioned to ESP32)
- 12V+ Power Supply → 12V+ (L298N)
- 12V- Power Supply → Ground (L298N)
The Problematic Connection
- Ground (ESP32) → Ground (L298N)
Issue Description
When I connect the ESP32 ground to the L298N ground, I observe the following problems:
- The DFPlayer Mini shorts out (sometimes burning and emitting smoke).
- Occasionally, the ESP32 throws the error:
Brownout detector was triggered
- If I disconnect the DFPlayer Mini, the ringer circuit works fine.
I've attached photos of my wiring and tried multiple configurations, but the issue persists. I also linked a YouTube video where someone uses a different motor driver—I've ordered the same one, but I’d like to understand what mistake I might have made with my current setup.
What I’ve Tried
- Removing the DFPlayer Mini: The rest of the circuit works fine.
- Checking the power connections: Everything seems correct.
- Trying different grounding configurations: Still results in the DFPlayer Mini failing.
Code
#include "HardwareSerial.h"
#include "DFRobotDFPlayerMini.h"
#define PHONE_PIN 4 // Pin to detect pickup/hang-up
#define DEBOUNCE_DELAY 100 // Debounce delay in milliseconds
#define PIN_MP3_TX 17 // TX to DFPlayer RX
#define PIN_MP3_RX 16 // RX to DFPlayer TX
const byte ringerPins[] = {25, 33};
// Phone state variables
bool lastState = HIGH;
bool currentState;
unsigned long lastDebounceTime = 0;
// Ringer variables
unsigned long lastRingTime = 0;
unsigned long ringDuration = 20;
unsigned long timeBetweenRings = 4000;
unsigned long shortDelayBetweenPatterns = 200;
int ringIterations = 20;
int ringRepeats = 2;
bool ringInProgress = false;
bool shouldRing = false;
// DFPlayer Mini
HardwareSerial mySerial(1);
DFRobotDFPlayerMini player;
bool shouldPlay = false;
void setup() {
Serial.begin(115200);
pinMode(PHONE_PIN, INPUT_PULLUP);
pinMode(ringerPins[0], OUTPUT);
pinMode(ringerPins[1], OUTPUT);
mySerial.begin(9600, SERIAL_8N1, PIN_MP3_RX, PIN_MP3_TX);
if (player.begin(mySerial)) {
Serial.println("DFPlayer Mini ready!");
player.volume(30);
} else {
Serial.println("Failed to connect to DFPlayer Mini!");
}
}
void detectPhoneState() {
int reading = digitalRead(PHONE_PIN);
if (reading != lastState) {
lastDebounceTime = millis();
}
if ((millis() - lastDebounceTime) > DEBOUNCE_DELAY) {
if (reading != currentState) {
currentState = reading;
if (currentState == LOW) {
Serial.println("Phone is PICKED UP");
} else {
Serial.println("Phone is HUNG UP");
}
}
}
lastState = reading;
}
void ringPattern() {
for (int j = 0; j < ringRepeats; j++) {
for (int i = 0; i < ringIterations; i++) {
digitalWrite(ringerPins[0], i % 2);
digitalWrite(ringerPins[1], 1 - (i % 2));
delay(ringDuration);
}
delay(shortDelayBetweenPatterns);
}
digitalWrite(ringerPins[0], LOW);
digitalWrite(ringerPins[1], LOW);
}
void parseCommand(String input) {
input.trim();
if (input == "ring") {
shouldRing = true;
Serial.println("Ringing started");
} else if (input == "stopring") {
shouldRing = false;
Serial.println("Ringing stopped");
digitalWrite(ringerPins[0], LOW);
digitalWrite(ringerPins[1], LOW);
} else if (input == "play") {
shouldPlay = true;
player.play(1);
Serial.println("Playing audio");
} else if (input == "stopplay") {
shouldPlay = false;
player.stop();
Serial.println("Audio stopped");
}
}
void loop() {
detectPhoneState();
while (Serial.available() > 0) {
String mystr = Serial.readString();
parseCommand(mystr);
}
if (shouldRing && millis() - lastRingTime > timeBetweenRings && !ringInProgress) {
ringInProgress = true;
ringPattern();
lastRingTime = millis();
ringInProgress = false;
}
}
Request for Help
- What could be causing the DFPlayer Mini to short out when I connect the L298N ground to the ESP32 ground?
- Could there be a ground loop or power isolation issue?
- Any suggestions on troubleshooting steps or modifications to prevent damage?
Thanks in advance for any help!
YouTube Video Reference:
