KY-004 Key Switch Module

The KY-004 Key Switch Module is a simple yet versatile input component designed for Arduino, Raspberry Pi, and other microcontroller-based projects. Built around a standard tactile push button mounted on a compact PCB, this module outputs a digital HIGH or LOW signal when the button is pressed — making it an ideal choice for triggering events, resetting circuits, or acting as a manual input in embedded systems.

Perfectly suited for beginners and experienced makers alike, the KY-004 features a three-pin interface (Signal, VCC, GND) that plugs directly into standard sensor shields or breadboards with no additional components required. The onboard resistor ensures stable signal output, eliminating the need for external pull-up or pull-down resistors in most applications.

Compact, reliable, and easy to integrate, this module is a staple in any electronics toolkit — whether you’re building a game controller, a security trigger, or a custom input device.

Specification:

• Operating Voltage : 3.3V – 5V DC
• Output Type : Digital (HIGH / LOW)
• Button Type : Tactile Push Button
• Pin Count : 3 (Signal, VCC, GND)
• PCB Dimensions : 15mm x 36mm
• Onboard Resistor : Yes
• Compatible With : Arduino, Raspberry Pi, ESP32/ESP8266
• Output Signal (Idle) : HIGH
• Output Signal (Pressed) : LOW