diff --git a/src/src/main.cpp b/src/src/main.cpp
index e55b7e4..722c928 100644
--- a/src/src/main.cpp
+++ b/src/src/main.cpp
@@ -1,8 +1,21 @@
 #include <Arduino.h>
+
+constexpr byte BTN = 6; // connected to GND on the other side
+constexpr byte ENCODER_CLK = 8;
+constexpr byte ENCODER_DT = 9;
+constexpr byte ENCODER_SW = 12;
+
+// common cathode
+constexpr byte RGB_G = 3;
+constexpr byte RGB_R = 5;
+constexpr byte RGB_B = 11;
+
+constexpr byte SERVO_PWM = 10;
+
 void setup() {
-// write your initialization code here
+
 }
 
 void loop() {
-// write your code here
+
 }
\ No newline at end of file