arduino: WT61 init logics & matched mounting

arduino/main/voltage.h

@@ -6,10 +6,17 @@
 // Initialize voltage monitoring (call in setup)
 void voltage_init();
 
-// Read battery voltage, returns volts (e.g., 12.5)
+// Set smoothing window size (1-32 samples, default 20)
+// Resets the buffer with current reading
+void voltage_set_smoothing(int windowSize);
+
+// Read battery voltage (smoothed), returns volts (e.g., 12.5)
 float voltage_read();
 
-// Read raw ADC value (0-1023)
+// Read smoothed ADC value (averaged over window)
+int voltage_read_smoothed();
+
+// Read raw ADC value (0-1023), no smoothing
 int voltage_read_raw();
 
 #endif