From 35906baf0c718c1341d1ffa240ec8a384e819fcd Mon Sep 17 00:00:00 2001
From: Denis Denisov <ftc.denis@gmail.com>
Date: Sun, 12 Sep 2021 16:02:12 +0300
Subject: [PATCH] Relay module firmware

---
 .gitignore                    |   1 +
 relay_module/config.h.sample  |   5 ++
 relay_module/relay_module.ino | 121 ++++++++++++++++++++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 relay_module/config.h.sample
 create mode 100644 relay_module/relay_module.ino

diff --git a/.gitignore b/.gitignore
index 391c872..0f2da10 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ thermo_sensor/config.h
 esp_server/.vs/
 esp_server/bin/
 esp_server/obj/
+relay_module/config.h
diff --git a/relay_module/config.h.sample b/relay_module/config.h.sample
new file mode 100644
index 0000000..9d6aa18
--- /dev/null
+++ b/relay_module/config.h.sample
@@ -0,0 +1,5 @@
+
+#define WIFI_NAME "your wi-fi name"
+#define WIFI_PASS "you wi-fi password" 
+#define REMOTE_ADDR "IP address of host to send data to"
+#define REMOTE_PORT 7000
diff --git a/relay_module/relay_module.ino b/relay_module/relay_module.ino
new file mode 100644
index 0000000..b137281
--- /dev/null
+++ b/relay_module/relay_module.ino
@@ -0,0 +1,121 @@
+#include <ESP8266WiFi.h>
+#include <WiFiUdp.h>
+#include "config.h"
+
+#define READ_INTERVAL 1000
+#define UDP_PORT 7000
+#define PING_INTERVAL 60000 // one minute seems to be ok for us
+#define RELAY_PIN 2
+
+WiFiUDP udp;
+char id[64];
+
+unsigned long last_ping;
+int relay_status = LOW;
+unsigned long last_send = 0;
+
+void setup() 
+{
+	Serial.begin(115200);
+	Serial.println("Initialised...");
+
+	WiFi.begin(WIFI_NAME, WIFI_PASS);
+	Serial.print("Connecting");
+	while (WiFi.status() != WL_CONNECTED)
+	{
+		delay(500);
+		Serial.print(".");
+	}
+	Serial.println();
+
+	Serial.print("Connected, IP address: ");
+	Serial.println(WiFi.localIP());
+	uint8_t macAddr[6];
+	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();
+	pinMode(RELAY_PIN, OUTPUT);
+	digitalWrite(RELAY_PIN, relay_status);
+}
+
+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");
+		last_ping = millis();
+	}
+	else if (strncmp(incoming_packet, "r_write", pos) == 0)
+	{
+		pos++;
+		int s = pos;
+		while (pos < len && incoming_packet[pos] != 0x01) pos++;
+		if (incoming_packet[s] == '0') relay_status = LOW;
+		else if (incoming_packet[s] == '1') relay_status = HIGH;
+		else Serial.println("Wrong state in incoming packet");
+		// to force re-send of current status
+		last_send = 0;
+	}
+	else
+	{
+		// unknown command
+		Serial.println("Unknown command received");
+	}
+}
+
+char payload[1024];
+
+void SendState()
+{
+	int len = snprintf(payload, sizeof(payload), "{\"r\":%d,\"id\":\"%s\",\"ip\":\"%s\"}", relay_status, id, WiFi.localIP().toString().c_str());
+	Serial.print("Sending payload:\n");
+	Serial.println(payload);
+
+	if (!udp.beginPacket(REMOTE_IP, REMOTE_PORT))
+	{
+		Serial.println("Error with destination ip or port");
+		return;
+	}
+	udp.write(payload, len);
+	udp.endPacket();
+}
+
+
+void loop() 
+{
+	unsigned long current = millis();
+	if (current < last_send || current - last_send >= READ_INTERVAL)
+	{
+		SendState();
+		last_send = current;
+	}
+	int packetSize = udp.parsePacket();
+	if (packetSize)
+	{
+		ParseIncomingPacket();
+	}
+	digitalWrite(RELAY_PIN, relay_status);
+	// renew current, because during processing of packet some time could pass
+	// and we will thing that last_ping is in future
+	current = millis();
+	if (current < last_ping || current - last_ping >= PING_INTERVAL)
+	{
+		// no pings for long time, reboot
+		Serial.println("No pings for long time, reboot");
+		Serial.println("Current");
+		Serial.println(current);
+		Serial.println("Last ping");
+		Serial.println(last_ping);
+		ESP.restart();
+	}
+}