// OLED display settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define FRAMERATE 8

// Buttons and buzzer
#define PIN_BTN_L 12 // D6
#define PIN_BTN_M 13 // D7
#define PIN_BTN_R 15 // D8
#define PIN_BUZZER 0 // D3

// Battery measurement
#define R1 220000.0 // 220k ohms
#define R2 56000.0  // 56k ohms
#define VOLTAGE_MAX 4.1 // Full battery voltage
#define VOLTAGE_MIN 3.0 // Empty battery voltage