Initial commit

src/main.cpp

@@ -0,0 +1,28 @@
+#include <Arduino.h>
+
+#define RELAY_PIN 0
+#define LED_PIN LED_BUILTIN
+
+void setup() {
+  pinMode(RELAY_PIN, OUTPUT);
+  pinMode(LED_PIN, OUTPUT);
+  digitalWrite(RELAY_PIN, LOW);
+  digitalWrite(LED_PIN, HIGH);
+  Serial.begin(115200);
+  Serial.println("Ready — send 1 (on) or 0 (off)");
+}
+
+void loop() {
+  if (Serial.available() > 0) {
+    char c = Serial.read();
+    if (c == '1') {
+      digitalWrite(RELAY_PIN, HIGH);
+      digitalWrite(LED_PIN, LOW);
+      Serial.println("ON");
+    } else if (c == '0') {
+      digitalWrite(RELAY_PIN, LOW);
+      digitalWrite(LED_PIN, HIGH);
+      Serial.println("OFF");
+    }
+  }
+}