Process2 Watch Dog Timer (WDT) Kit.

Purpose of the WDT:

Connect the WDT to your Arduino (or other compatible MCU) in order to provide your 'Arduino' with a watch dog timer. It is a simple two wire hookup (not counting +5V and GND).
If the WDT does not receive a 'heartbeat' from the Arduino within a set time, the WDT will reset the Arduino. A reset prevents the Arduino from locking up due to poor code and/or unexpected event(s).

Construction/Wiring Directions:

Solder all components as shown in the following assembly photo. Be careful, as some components have required orientation.

Specs as provided in the kit are as follows:

• Pulse width: ~400 ms
• Time between pulses: ~(2 minutes and 15 seconds) or (~135 seconds)
• Voltage before pulse, at pulse, and after pulse: 5 V to 0.6 V to 5 V

				
//.ino code-

//sample code for the WDT, this code run on the Arduino Leonardo-

int pulsePin = 8;
unsigned long lastHeartbeat = 0;
unsigned long lastUptimeReport = 0;

void heartbeat() {
  // bring pin low to sink current, to drain charge from watchdog circuit
  pinMode(pulsePin, OUTPUT);
  digitalWrite(pulsePin, LOW);
  delay(300);
  // Return to high-impedance
  pinMode(pulsePin, INPUT);
  lastHeartbeat = millis();
  Serial.println("Heartbeat sent");
}


void setup() {
  Serial.begin(9600);  
  Serial.println("Arduino startup/reset");
  // Send an initial heartbeat.
  heartbeat();
}


void loop() {
  // Check for serial inputs. (This is done in the serial monitor.)
  // If found, send a heartbeat.
  if (Serial.available()) {
    // Clear input buffer
    while (Serial.available()) {
      Serial.read();
    }
    heartbeat();
  }
  unsigned long uptime = millis();
  if ((uptime - lastUptimeReport) >= 5000) {
    // It has been at least 5 seconds since our last uptime status.  
    Serial.println("Uptime: " + String((uptime - (uptime % 5000)) / 1000) + " seconds (" + String((uptime - lastHeartbeat) / 1000) + " seconds since last heartbeat)");
    lastUptimeReport = (uptime - (uptime % 5000));
  }
  // delay in between loops
  delay(100);
}