Implement I2C support into firmware

envisens/atmega_fw/atmega_fw.ino

@@ -31,6 +31,12 @@ void setup() {
   pinMode(LED_BUILTIN, OUTPUT); 
   digitalWrite(LED_BUILTIN, LOW);
   dht.begin();
+  Wire.begin(8);                // join i2c bus with address #8
+  Wire.onRequest(requestEvent); // register event
+}
+
+void requestEvent() {
+  Wire.write("he1234");
 }
 
 void loop() {