After using TCPClient, core becomes unstable

Troubleshooting
1

Hi, I am trying to make a sound monitor, so I can see if my dog is barking during the day while I’m away. I’ve got an adafruit microphone (https://www.adafruit.com/products/1063) which can be read via analogRead.

The code below works for the first iteration. The expected output is written to the serial port through “Done.” The reading shows up on thingspeak. After that, the Spark becomes unstable and the code never seems to run again. The spark will continually drop the wifi connection (flashing fast green and fast cyan). I can’t program it again without factory resetting it.

I’m a bit at a loss here. Any ideas on what I’m doing wrong?

Thanks,
Grady

byte server[]  = { 184, 106, 153, 149 }; // IP Address for the ThingSpeak API
String writeAPIKey = "API KEY";    // Write API Key for a ThingSpeak Channel

TCPClient client;

void setup() {
    pinMode(A4, INPUT);
    
    Serial.begin(9600);
    Serial.println("hello");
}

void loop() {
    unsigned int loudness = 0;
    
    
    //sample the loudness for about a minute
    Serial.println("sampling");
    for ( int n=0; n < 50; n++ ) {

        for (int i=0; i < 10; i++) {
            unsigned long startMillis = millis();  // Start of sample window
         
            unsigned int signalMax = 0;
            unsigned int signalMin = 10000;
        
            while ( millis() - startMillis < 25 ) {
                unsigned int sample = analogRead(A4); //P5    
            
                signalMax = max(signalMax, sample);
                signalMin = min(signalMin, sample);
            }
        
            loudness = max(signalMax - signalMin, loudness);  // max - min = peak-peak amplitude
        }
        
        Serial.println(loudness);
        delay(1000);
    }
    
    if ( client.connect(server, 80) ) {
        Serial.println("connected");    

        String tsData = "field1="+String(loudness);
        
        client.print("POST /update HTTP/1.1\n");
        client.print("Host: api.thingspeak.com\n");
        client.print("Connection: close\n");
        client.print("X-THINGSPEAKAPIKEY: "+writeAPIKey+"\n");
        client.print("Content-Type: application/x-www-form-urlencoded\n");
        client.print("Content-Length: ");
        client.print(tsData.length());
        client.print("\n\n");
        client.print(tsData);

        //wait for request to be processed.
        delay(1000);        

        Serial.print("and ");
        client.flush();
        client.stop();
    }
    
    Serial.println("done");
}
3 Likes
2

I’m not 100% sure @gradymorgan, but here’s a theory. The Core does a little heartbeat back and forth with the Spark Cloud so it knows when the connection has dropped and it has to reconnect. How long does your loop() take to run? If it’s more than about 10 seconds, the Core might think the server has gone away.

2 Likes
3

From the code his loop is at least 51 seconds, so it sounds like that could definitely be the problem.

4

Yup, that seems to have done it. Their maximum write rate is once every 15 seconds, so every variation I had tried involved loop() being at least that long. Thanks zachary!

1 Like