Added documentation. Added keep-alive cheking to thermo_sensor

thermo_sensor/thermo_sensor.ino

@@ -6,12 +6,15 @@
 #define DHTPIN 5
 #define DHTTYPE DHT22
 #define READ_INTERVAL 1000
-
+#define UDP_PORT 7000
+#define PING_INTERVAL 60000 // one minute seems to be ok for us
 
 WiFiUDP udp;
 DHT dht(DHTPIN, DHTTYPE);
 char id[64];
 
+long last_ping;
+
 void setup() 
 {
 	Serial.begin(115200);
@@ -34,6 +37,9 @@ void setup()
 	WiFi.macAddress(macAddr);
 	sprintf(id, "%02x:%02x:%02x:%02x:%02x:%02x", macAddr[0], macAddr[1], macAddr[2], macAddr[3], macAddr[4], macAddr[5]);
 	Serial.printf("Connected, mac address: %s\n", id);
+	udp.begin(UDP_PORT);
+
+	last_ping = millis();
 }
 
 char payload[1024];
@@ -73,6 +79,28 @@ void ReadAndSend()
 	udp.endPacket();
 }
 
+
+
+char incoming_packet[4096];
+
+void ParseIncomingPacket()
+{
+	int len = udp.read(incoming_packet, sizeof(incoming_packet));
+	if (len == 0) return;
+	// find command
+	int pos = 0;
+	while (pos < len && incoming_packet[pos] != 0x01) pos++;
+	if (strncmp(incoming_packet, "ping", pos) == 0)
+	{
+		Serial.println("Ping command received");
+	}
+	else
+	{
+		// unknown command
+		Serial.println("Unknown command received");
+	}
+}
+
 unsigned long last_read = 0;
 
 void loop() 
@@ -83,4 +111,15 @@ void loop()
 		ReadAndSend();
 		last_read = current;
 	}
+	int packetSize = udp.parsePacket();
+	if (packetSize)
+	{
+		ParseIncomingPacket();
+	}
+	if (current < last_ping || current - last_ping >= PING_INTERVAL)
+	{
+		// no pings for long time, reboot
+		Serial.println("No pings for long time, reboot");
+		ESP.restart();
+	}
 }