Add schema diagram and hardware debouncing instructions to README.md

arduino/README.md

@@ -42,6 +42,12 @@ A game controller using a Seeed Studio XIAO nRF52840 Sense board that emulates a
 - **Character Mapping:** Each button event sends a unique character.
 - **Serial Debugging:** Outputs button events and Bluetooth connection status to the serial monitor.
 
+## Schema
+
+Connect each button to its corresponding pin. For reliable input readings add hardware debouncing: use a pull-up resistor 10 kΩ and an RC filter with a 100 nF capacitor across the switch — an RC time constant around 1 ms works well.
+
+![Schema](Schema.png)
+
 ## Button Mappings
 
 | Button | Single Click | Double Click | Long Press |