kitchen_pilot_wire_control.ino: add a loop watchdog

soft/kitchen/kitchen_pilot_wire_control/kitchen_pilot_wire_control.ino

@@ -3,8 +3,12 @@
   Switches on or off a heater.
 */
 
+#include <Ticker.h>
+
 #include "EspMQTTClient.h"
 
+#define LWD_TIMEOUT_MS  15000
+
 EspMQTTClient client(
   "rico",
   "xxxxxx",
@@ -30,6 +34,10 @@ const int led_pin = 2;
   digitalWrite(pin, HIGH); \
 } while(0)
 
+// loop watchdog variables
+unsigned long lwdTime = 0;
+unsigned long lwdTimeout = LWD_TIMEOUT_MS;
+Ticker lwdTicker;
 
 os_timer_t keep_alive_timer;
 
@@ -40,6 +48,19 @@ void reset_timer(os_timer_t *timer)
   os_timer_arm(timer, 3600000, false);
 }
 
+void ICACHE_RAM_ATTR lwdtcb(void)
+{
+  if (((millis() - lwdTime) > LWD_TIMEOUT_MS) || ((lwdTimeout - lwdTime) != LWD_TIMEOUT_MS))
+  {
+    ESP.restart();
+  }
+}
+
+void lwdtFeed(void) {
+  lwdTime = millis();
+  lwdTimeout = lwdTime + LWD_TIMEOUT_MS;
+}
+
 void message_callback(const String &message)
 {
   Serial.println(message);
@@ -101,4 +122,5 @@ void loop()
     led_on(led_state);
   }
   counter++;
+  lwdtFeed();
 }