Mega 2560 and Ethernet shield

Projects General Guidance
1

Hi,

I have a problem with a project of mine. I use a Mega2560 to read temperature and light sensors with 1 second frequency. The readings are sent on the network to a server where is processed.
My problem is that, after a while (couple minutes) the arduino no longer respond to the server requests. If I activate the serial monitor from the laptop (now the board is powered and connected on USB) I see that the setup() method is called again and the board start responding again. But only for couple of minutes. Probably the board is entering in sleep mode but I didn't find a method to disable this permanently (I need the board to work always because he needs to read sensors and communicate with the server continuously).
I need some help with this, any suggestion would be appreciated.
Thank you.

2

You should post your code. Here is my ethernet client code:
http://playground.arduino.cc/Code/WebClient

It should not be entering a sleep mode. It is probably running out of sockets on the w5100.

3 
//timer 1Hz
ISR(TIMER3_COMPA_vect) { 
  cal.incrementSecond();
  connectedCounterCheck++;
  power_all_enable();
  sleep_disable();
  if (connectedCounterCheck>waitPeriodBeforeDisconnected){
    digitalWrite(DISCONNECTED_PIN, LOW);
    isConnected = 0;
  } else { 
    temp1 = readTemperature(temperatureSensor1);
    temp2 = readTemperature(temperatureSensor2);
    lightSensor = String(analogRead(LIGHT_SENSOR_PIN));
    String val = "<root>";
    val += "<temp><t1>"+temp1+"</t1><t2>"+temp2+"</t2></temp><light>"+lightSensor+"</light>";
    val += "</root>";
    sendToServer(val);
  }
}

void setup() {
  Ethernet.begin(mac,ip);
  Udp.begin(localPort);
  UdpRet.begin(localPort);
  //22...35 digital out - 13 out
  pinMode(DISCONNECTED_PIN, OUTPUT);
  pinMode(23, OUTPUT);
  pinMode(24, OUTPUT);
  pinMode(25, OUTPUT);
  pinMode(26, OUTPUT);
  pinMode(27, OUTPUT);
  pinMode(28, OUTPUT);
  pinMode(29, OUTPUT);
  pinMode(30, OUTPUT);
  pinMode(31, OUTPUT);
  pinMode(32, OUTPUT);
  pinMode(33, OUTPUT);
  pinMode(34, OUTPUT);
  pinMode(35, OUTPUT);
  
  pinMode(36, INPUT);
  pinMode(37, INPUT);
  pinMode(38, INPUT);
  pinMode(39, INPUT);
  pinMode(40, INPUT);
  pinMode(41, INPUT);
  pinMode(42, INPUT);

  pinMode(43, INPUT);
  pinMode(44, INPUT);
  pinMode(45, INPUT);
  pinMode(46, INPUT);

  pinMode(47, INPUT);
  pinMode(48, INPUT);
  pinMode(49, INPUT);
  pinMode(50, INPUT);
  
  pinMode(LIGHT_SENSOR_PIN, INPUT);
  digitalWrite(LIGHT_SENSOR_PIN, HIGH);
    
  noInterrupts();           // disable all interrupts
  TCCR3A = 0;
  TCCR3B = 0;
  TCNT3  = 0;

  OCR3A = 62500;            // compare match register 16MHz/512/1Hz
  TCCR3B |= (1 << WGM32);   // CTC mode
  TCCR3B |= (1 << CS32);    // 256 prescaler 
  TIMSK3 |= (1 << OCIE3A);  // enable timer compare interrupt
  interrupts();         

  Serial.begin(9600);
  Serial.println("intialization complete");
  sleep_disable();
}

void loop()
  int packetSize = Udp.parsePacket();
  int test = 0;
  if(packetSize)
  {
    String val = "";
    IPAddress remote = Udp.remoteIP();
    Udp.read(packetBuffer,UDP_TX_PACKET_MAX_SIZE);
    Udp.flush();
    String request = String(packetBuffer);
    for(int i=0;i<UDP_TX_PACKET_MAX_SIZE;i++) packetBuffer[i] = 0;
    String cmd = getCommand(request);
    Serial.println("Received: "+request);
    if (cmd == "s") {  //ping
      setConnected();
      int check = cal.mustSyncTime();
      if (check == 1) {
       //sync time from server info
        setTime(request);
      }
    } else if (cmd == "w") {  //write settings

    } else if (cmd == "c") {  //change setting
      setConnected();
      String option = getOption(request);
      String value = getOptionValue(request);
      value.trim();
      int pin = option.toInt();
      uint8_t pinShort = uint8_t(pin);
      pinMode(pinShort, OUTPUT);
      if (value == "off"){
        digitalWrite(pinShort, LOW);
      } else {
        digitalWrite(pinShort, HIGH);
      }
    }
  }
  int button = 0;
  int checkIfMustSend = 0;
  for (int i=0; i<12; i++){
    int pin = 36+i;
    button = digitalRead(pin);
    if (input[i] != button) {
      checkIfMustSend = 1;
      input[i] = button;
    }
  }
  if (checkIfMustSend == 1){
      String val = "<root><button>";
      for (int i=0; i<12; i++){
        val += "<b"+String(i)+">"+input[i]+"</b"+String(i)+">";
      }
      val += "</button></root>";
      sendToServer(val);
  }
  delay(10);
}

This is the code. I already try to disable the sleep mode but it seems that is not working. I am new on Arduino programming.

4

That is not all the code. Where is this function?

sendToServer(val);

Are you using UDP or TCP? Either way, calling an ethernet function from an interrupt is not a good idea. Many functions count on the time for delays, and it isn't working right in an interrupt.

5

UDP. I need to call this from the interrupt because I need to send the status of the sensors with at 1s interval.

6

There are other ways to do that without an interrupt. You can use a delay(1000) or use millis() to determine a second.

void loop()
{
    IPAddress udpIP(1,2,3,4);
    int udpPort = 8888;

    char msg[] = "blablabla";
    Udp.beginPacket(udpIP, udpPort);
    Udp.write(msg);
    Udp.endPacket();
    delay(1000); 
}
7

I cannot put a delay because I also need (in loop) to read the status of some inputs (sensors and command buttons) but it seems that, if I move the send to server logic from the interrupt and added to the loop method works. I set a variable on the interrupt method when it's called and then, in loop, if this is set, the I read the sensors and send to server (also reset the variable). Seems that this works ok.
Thank you very much for your help.

8

You may have memory problems. Try setting all your variables to "" at the end of each loop where they are used.