Splashr -- RobotsConf 2013 Hack

splashr.ino

const int ledPin = D1;
const int waterSensor = A0;

int wetStatus = 0;
int lastWetStatus = 0;
int waterAvg = 0;
int smsActive = 0;

// Endpoint must deliver SMS message when root HTTP request is received.
// Real implementation would have to somehow retrieve a token so that
// server would associate valid Twilio credentials with the device token.
// This is necessary because the Spark Core can not make an HTTPS request.
TCPClient client;
byte ip[] = { 192, 168, 1, 123 };

int waterRead(int ms) {
    // Return ADC average value over 8 reads.
    int avg = 0;
    for(int x = 0; x < 8; x++) {
        avg += analogRead(waterSensor);
        delay(ms);
    }
    avg /= 8;
    return avg;
}

void setup() {
    // Enable serial console output.
    Serial.begin(9600);
    delay(1000);
    Serial.println("Initializing...");
    
    pinMode(ledPin, OUTPUT);
    digitalWrite(ledPin, LOW);

    // Calculate ADC average to compare against in runtime loop.   
    pinMode(waterSensor, INPUT_PULLUP);
    waterAvg = waterRead(50);
    digitalWrite(ledPin, LOW);
    Serial.print("Water Avg: ");
    Serial.println(waterAvg);
}

void sms() {
    smsActive = 1;
    if (client.connect(ip, 8080)) {
        Serial.println("Connected.");
        client.println("GET / HTTP/1.1");
        client.println();
    } else {
        Serial.println("Connection failed.");
    }
}

void loop() {
    // Handle socket I/O, cleanup before sensor read.
    if (client.connected() && client.available()) {
        char c = client.read();
        Serial.print(c);
    }
    if (smsActive && !client.connected()) {
        Serial.println();
        Serial.println("Socket disconnected.");
        client.stop();
        smsActive = 0;
    }

    // Check for significant difference in conductivity over avg.
    int waterDifference = abs(waterRead(5) - waterAvg);
    Serial.print("Water avg: ");
    Serial.println(waterAvg);
    Serial.print("Water diff: ");
    Serial.println(waterDifference);
    if (waterDifference > 100) {
        wetStatus = HIGH;
    } else {
        wetStatus = LOW;
    }

    // Check for status change since last loop pass and act accordingly.
    if (wetStatus != lastWetStatus) {
        if (wetStatus == HIGH) {
            Serial.println("Water detected!");
            sms();
            digitalWrite(ledPin, HIGH);
        } else {
            Serial.println("Subject is dry.");
            digitalWrite(ledPin, LOW);
        }
    }
    lastWetStatus = wetStatus;
}