NodeMCU stops responding after several hours

Question

I'm controlling some devices through a relay and a NodeMCU, it works fine and reconnects without problem in the meantime I'm testing it, but after I leave it like for 3 or more hours, it stops responding. I need this system to always be working without sleeping or anything. Here is my code:

#include <ESP8266WiFi.h>
const char* ssid = "wifi_Guerrero ";
const char* password = "3245968530";
int ledPin = 13; // GPIO13
int ledPin2 = 12; // GPIO13
int desconectado = 5;
int conectado = 4;
WiFiServer server(80);
WiFiClient client;
int counter = 0;
void setup() {
 Serial.begin(9600);
 delay(10);
 pinMode(ledPin, OUTPUT);
 digitalWrite(ledPin, LOW);
 pinMode(ledPin2, OUTPUT);
 digitalWrite(ledPin2, LOW);
 pinMode(conectado, OUTPUT);
 pinMode(desconectado, OUTPUT);
 digitalWrite(desconectado, HIGH);
 connectWifi(); 
 Serial.print(F("Setting static ip to : "));
 Serial.println(WiFi.localIP()); 
 // Start the server
 server.begin();
 Serial.println("Server started");
}
void loop() {
 delay(200);
 if (WiFi.status() != WL_CONNECTED) {
 delay(100);
 digitalWrite(conectado, LOW);
 digitalWrite(desconectado, HIGH);
 connectWifi(); 
 }
 // Check if a client has connected
 client = server.available();
 if (!client) {
 return;
 }
 // Wait until the client sends some data
 Serial.println("new client");
 int t = millis();
 while(!client.available()){
 delay(1);
 if (millis()-t>130) return;
 }
 // Read the first line of the request
 String request = client.readStringUntil('\r');
 Serial.println(request);
 client.flush();
 // Match the request
 if (request.indexOf("/switch") != -1) {
 digitalWrite(ledPin, !digitalRead(ledPin));
 digitalWrite(ledPin2, !digitalRead(ledPin2));
 printSwitch();
 }else if (request.indexOf("/uno") != -1) {
 client.print("Canal 1 apagagado | Canal 2 encendido");
 digitalWrite(ledPin, HIGH);
 digitalWrite(ledPin2, LOW);
 }else if (request.indexOf("/dos") != -1){
 client.print("Canal 1 encendido | Canal 2 apagado");
 digitalWrite(ledPin, LOW);
 digitalWrite(ledPin2, HIGH);
 }else if (request.indexOf("/tres") != -1){
 client.print("Canal 1 apagado | Canal 2 apagado");
 digitalWrite(ledPin, HIGH);
 digitalWrite(ledPin2, HIGH);
 }else if (request.indexOf("/cuatro") != -1){
 client.print("Canal 1 encendido | Canal 2 encendido");
 digitalWrite(ledPin, LOW);
 digitalWrite(ledPin2, LOW);
 }else if (request.indexOf("/cinco") != -1){
 printIP();
 }else if (request.indexOf("/apagaruno") != -1){
 client.print("Canal 1 apagado");
 digitalWrite(ledPin, HIGH);
 }else if (request.indexOf("/apagardos") != -1){
 client.print("Canal 2 apagado"); 
 digitalWrite(ledPin2, HIGH);
 }else if (request.indexOf("/prenderuno") != -1){
 client.print("Canal 1 encendido");
 digitalWrite(ledPin, LOW);
 }else if (request.indexOf("/prenderdos") != -1){
 client.print("Canal 2 encendido");
 digitalWrite(ledPin2, LOW);
 }else if (request.indexOf("/canaluno") != -1){
 if(digitalRead(ledPin) == HIGH) { 
 client.print("Off");
 } else {
 client.print("On"); 
 }
 }else if (request.indexOf("/canaldos") != -1){
 if(digitalRead(ledPin2) == HIGH) { 
 client.print("Off");
 } else {
 client.print("On");
 }
 }
// Set ledPin according to the request
//digitalWrite(ledPin, value);
 // Return the response 
 delay(1);
 Serial.println("Client disonnected");
 Serial.println("");
}
void printSwitch(){ 
 if(digitalRead(ledPin) == LOW) {
 client.print("Canal 1 Encendido");
 } else {
 client.print("Canal 1 Apagado");
 }
 Serial.println("");
 if(digitalRead(ledPin2) == LOW) {
 client.print("Canal 2 Encendido");
 } else {
 client.print("Canal 2 Apagado");
 }
}
void printIP(){
 delay(100); 
 client.print(WiFi.localIP());
}
void connectWifi()
{
 Serial.print("Connecting to "+*ssid);
 WiFi.begin(ssid, password);
 while (WiFi.status() != WL_CONNECTED) {
 delay(500);
 Serial.print(".");
 } 
 // config static IP
 IPAddress ip(192, 168, 0, 8);
 IPAddress gateway(192, 168, 0, 1);
 IPAddress subnet(255, 255, 255, 0); 
 WiFi.config(ip, gateway, subnet);
 digitalWrite(conectado, HIGH);
 digitalWrite(desconectado, LOW);
 Serial.println("");
 Serial.println("Connected");
 Serial.println(""); 
 // Print the IP address
 Serial.print("Use this URL to connect: ");
 Serial.print("http://");
 Serial.print(WiFi.localIP());
 Serial.println("/");
}//end connect

• Chris Stratton: You need to understand why it is stopping. Start with something like printing serial log messages and capturing them to a log file that you can examine after failure. Preferably do this over a pure UART connection (to a distinct USB to logic-level-serial) without using the on-board USB converter, unless you plan to have the USB connected to a PC in operation. Though you can of course start with the on-board USB and see if you learn something, it's just that there's a risk that having that plugged in could hide power-related failure causes.
• Chris Stratton: You should also consider if there are design errors in your unspecified electrical circuit. Particularly things like insufficient input voltage to a regulator, relay coils without catch diodes, or any sharing of the logic and load power supplies.
• Javier Guerrero: I think the problem is not about the circuit or power supply, because I also left it on AP mode and when the static ip I assigned to it stopped responding, I connected directly to it's AP with 192.168.4.1 and it responded, after trying that, I tried again with static IP and worked fine, it seems like it sleeps or something programatically
• David Klempfner: The answer here might help you: arduino.stackexchange.com/questions/75494/…

Answer 1

I think thatthe problem lies with this definition

String request = client.readStringUntil('\r');

which you define dynamically in loop this leads possibly to heap fragmentation, causing resets after sometime
Define a global char array

char request [256] ={'0円'};
char c;
uint cc = 0;

and work instead the String functions with

while(client.available()){ 
c = client.read(); 
if (c != '\r'){ 
 request[cc] = c;
 cc++;
 }
 else return;
}

then handle the filled request buffer like

if (strcmp(request,"/switch") != 0) {
 ....
 }

This should keep you esp running

• David Klempfner: That doesn't compile. You need a closing round bracket in your while loop. I also get: error: empty character constant char c = ''
• Delta_G: You need to add a line where you’re reading into that buffer to make sure you don’t overrun. Make sure cc doesn’t go over 255.