diff --git a/ESP32-IDF_ESPNOW-Transmitter/main/joystick.c b/ESP32-IDF_ESPNOW-Transmitter/main/joystick.c
index ccbe1d1e5..c0e011f10 100644
--- a/ESP32-IDF_ESPNOW-Transmitter/main/joystick.c
+++ b/ESP32-IDF_ESPNOW-Transmitter/main/joystick.c
@@ -19,7 +19,7 @@ adc_oneshot_unit_handle_t adc_xy_handle;
 sensors_data_t buffer;
 static int x, y; // Joystick x- and y- axis positions
 
-esp_err_t joystick_adc_init(void) 
+static esp_err_t joystick_adc_init(void) 
 {
     adc_oneshot_unit_init_cfg_t adc_init_config_xy = {
         .unit_id = ADC_UNIT_1,