How to Use SW-18020P: Examples, Pinouts, and Specs

The SW-18020P is a miniature push-button switch designed for user input in electronic devices. Its compact design and reliable performance make it a popular choice for applications requiring tactile feedback and precise control. This switch is commonly used in consumer electronics, industrial control panels, and DIY electronics projects. Its small size allows it to fit into space-constrained designs, while its durability ensures long-term functionality.

• User input in consumer electronics (e.g., remote controls, calculators)
• Control panels for industrial equipment
• DIY electronics and prototyping
• Reset or mode selection buttons in embedded systems

The SW-18020P is a simple, normally open (NO) push-button switch. Below are its key technical details:

The SW-18020P has two pins, as it is a simple single-pole, single-throw (SPST) switch. The pin configuration is as follows:

When the button is pressed, the circuit between Pin 1 and Pin 2 is closed, allowing current to flow.

1. Basic Connection: Connect one pin of the SW-18020P to the positive voltage source (e.g., 5V) and the other pin to the input of your circuit or microcontroller. Use a pull-down resistor (e.g., 10kΩ) to ensure the input pin reads a low state when the button is not pressed.
2. Debouncing: Mechanical switches like the SW-18020P may produce noise or "bouncing" when pressed. To avoid erratic behavior, use a debouncing circuit (e.g., an RC filter) or implement software debouncing in your microcontroller code.
3. Mounting: The SW-18020P is typically mounted on a PCB. Ensure the pins are soldered securely for reliable operation.

• Do not exceed the maximum voltage (12V DC) or current (50mA) ratings to avoid damaging the switch.
• Avoid exposing the switch to extreme temperatures or moisture, as this may degrade its performance.
• Use a pull-up or pull-down resistor to stabilize the input signal when connecting the switch to a microcontroller.

Below is an example of how to connect and use the SW-18020P with an Arduino UNO:

• Connect one pin of the SW-18020P to digital pin 2 on the Arduino.
• Connect the other pin to ground (GND).
• Add a 10kΩ pull-up resistor between digital pin 2 and 5V.

// SW-18020P Example Code for Arduino UNO
// This code reads the state of the push-button switch and turns on an LED
// connected to pin 13 when the button is pressed.

const int buttonPin = 2;  // Pin connected to the SW-18020P
const int ledPin = 13;    // Pin connected to the LED

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // Set button pin as input with internal pull-up
  pinMode(ledPin, OUTPUT);         // Set LED pin as output
}

void loop() {
  int buttonState = digitalRead(buttonPin); // Read the button state

  if (buttonState == LOW) { // Button pressed (LOW due to pull-up resistor)
    digitalWrite(ledPin, HIGH); // Turn on the LED
  } else {
    digitalWrite(ledPin, LOW);  // Turn off the LED
  }
}

1. Button Not Responding

   • Cause: Poor soldering or loose connections.
   • Solution: Check and re-solder the connections. Ensure the pins are securely connected to the circuit.

2. Erratic Behavior When Pressed

   • Cause: Switch bouncing.
   • Solution: Add a debouncing circuit (e.g., an RC filter) or implement software debouncing in your code.

3. Switch Fails to Close the Circuit

   • Cause: Exceeded voltage or current ratings, causing internal damage.
   • Solution: Replace the switch and ensure the circuit operates within the specified ratings.

4. Button Feels Stiff or Unresponsive

   • Cause: Mechanical wear or debris inside the switch.
   • Solution: Replace the switch if it has exceeded its mechanical durability.

Q: Can I use the SW-18020P with a 3.3V microcontroller?
A: Yes, the SW-18020P can operate at lower voltages like 3.3V, as long as the current does not exceed 50mA.

Q: Do I need an external pull-up resistor if my microcontroller has internal pull-ups?
A: No, you can use the microcontroller's internal pull-up resistor by configuring the input pin accordingly.

Q: How do I clean the SW-18020P if it gets dirty?
A: Use compressed air or a small brush to remove debris. Avoid using liquids, as they may damage the switch.

Q: Can the SW-18020P handle AC voltage?
A: No, the SW-18020P is designed for DC voltage only. Using it with AC voltage may damage the switch or cause unsafe operation.