main_pilot_wire_control: add also a loop watchdog

soft/main_pilot_wire_control/main_pilot_wire_control.ino

@@ -3,8 +3,12 @@
   Switches on or off several heaters.
 */
 
+#include <Ticker.h>
+
 #include "EspMQTTClient.h"
 
+#define LWD_TIMEOUT_MS  15000
+
 EspMQTTClient client(
   "rico2",
   "xxxxx",
@@ -33,6 +37,12 @@ struct heater {
 
 static struct heater heaters[NB_HEATERS];
 
+const int led_pin = 2;
+
+#define led_on(state) do {\
+  digitalWrite(led_pin, (state) ? LOW : HIGH); \
+} while (0)
+
 #define heater_on(pin) do {\
   digitalWrite(pin, LOW); \
 } while(0)
@@ -41,6 +51,10 @@ static struct heater heaters[NB_HEATERS];
   digitalWrite(pin, HIGH); \
 } while(0)
 
+// loop watchdog variables
+unsigned long lwdTime = 0;
+unsigned long lwdTimeout = LWD_TIMEOUT_MS;
+Ticker lwdTicker;
 
 void reset_timer(enum rooms room)
 {
@@ -51,6 +65,19 @@ void reset_timer(enum rooms room)
   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 handle_message(enum rooms room, const String &message)
 {
   Serial.println(message);
@@ -146,6 +173,9 @@ void onConnectionEstablished()
 
 void loop()
 {
+  static unsigned int counter;
+  static bool led_state = false;
+
   client.loop();
   if (!client.isConnected()) {
     // if something wrong happens, switch off the heater
@@ -153,4 +183,12 @@ void loop()
       heater_off(heaters[i].pin);
     }
   }
+
+  // blink ESP blue led to show that we are alive
+  if (((led_state) && (counter % 1000 == 0)) || (!led_state && (counter % 30000 == 0))) {
+    led_state = !led_state;
+    led_on(led_state);
+  }
+  counter++;
+  lwdtFeed();
 }