KW11-3Z Micro Limit Switch with Lever – 2-Pin Normally Open 5A 250VAC

Wiring & getting started

Wiring diagramArduino Nano

1. Find the two tabs

   Hold the switch with the numbered face towards you and the lever pivot on the left. Tab 1 at the pivot end is COM and tab 3 in the middle is NO. On the back face the same two tabs are marked C and NO. The far end, marked 2 and NC, has no tab.

2. Connect the wires

   Wire C to GND and NO to D2 on an Arduino Nano or Uno, as in the drawing. On an ESP32 or Raspberry Pi Pico, use GND and any input pin and change the pin number in the code. The switch carries no voltage of its own, so 3.3V boards are fine.

3. Load the test code

   Upload this sketch, then open the Serial Monitor at 9600 baud.

   Example Arduino codeArduino C++

   // KW11-3Z 2-pin lever switch test. Wire C to GND and NO to D2.
   const int SWITCH_PIN = 2;
   bool wasPressed = false;
   
   void setup() {
     pinMode(SWITCH_PIN, INPUT_PULLUP);  // uses the Nano's built-in resistor
     Serial.begin(9600);
     Serial.println("Ready. Press the lever.");
   }
   
   void loop() {
     bool pressed = digitalRead(SWITCH_PIN) == LOW;  // LOW while the lever is pressed
     if (pressed != wasPressed) {
       Serial.println(pressed ? "PRESSED" : "RELEASED");
       wasPressed = pressed;
       delay(20);  // ignore contact bounce
     }
   }

4. Check it works

   Press the lever and the Serial Monitor shows PRESSED. Let go and it shows RELEASED. If nothing changes, check that the wires are on the C and NO tabs and that NO goes to the pin named in the code.

5. Mount it

   Fix the switch with two M2 screws so the moving part presses the lever near its tip at the end of travel. Leave a little travel past the click, so the part stops on its own end stop and never jams against the switch body.