first upload

examples/Slave/Slave.ino

@@ -0,0 +1,65 @@
+#include <Wire.h>
+#include <EEPROM.h>
+
+// EEPROM settings
+#define ADDR_EEPROM_LOC 0
+#define EEPROM_SIZE 64
+
+// Relay pins: GPIO0 to GPIO7
+const int relayPins[8] = {0, 1, 2, 3, 4, 5, 6, 7}; // GPIOs 0-7
+
+uint8_t i2cAddress;
+
+// Unified I2C receive event
+void receiveEvent(int howMany) {
+  if (howMany >= 2) {
+    uint8_t first = Wire.read();
+    uint8_t second = Wire.read();
+
+    // Check for address change command
+    if (first == 0xAA) {
+      // Change I2C address and store in EEPROM
+      uint8_t newAddr = second;
+      EEPROM.write(ADDR_EEPROM_LOC, newAddr);
+      EEPROM.commit();
+      Serial.print("I2C address changed to: 0x");
+      Serial.println(newAddr, HEX);
+      delay(100);
+      ESP.restart();
+      return;
+    }
+
+    // Otherwise, treat as relay control
+    int relay = first;   // Relay number: 1-8
+    int state = second;  // State: 1=ON, 0=OFF
+    if (relay >= 1 && relay <= 8) {
+      digitalWrite(relayPins[relay - 1], state ? LOW : HIGH); // Active LOW relays
+    }
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+  EEPROM.begin(EEPROM_SIZE);
+
+  // Read I2C address from EEPROM or use default
+  i2cAddress = EEPROM.read(ADDR_EEPROM_LOC);
+  if (i2cAddress == 0xFF || i2cAddress == 0) i2cAddress = 0x08; // Default address
+
+  Serial.print("Using I2C address: 0x");
+  Serial.println(i2cAddress, HEX);
+
+  // Initialize relay pins
+  for (int i = 0; i < 8; i++) {
+    pinMode(relayPins[i], OUTPUT);
+    digitalWrite(relayPins[i], HIGH); // Relays OFF initially (active LOW)
+  }
+
+  // Start I2C slave
+  Wire.begin(i2cAddress);
+  Wire.onReceive(receiveEvent);
+}
+
+void loop() {
+  // Nothing needed here for basic operation
+}