SW-420 Normally Closed Vibration Sensor Switch

SW-420 Normally Closed Vibration Sensor Switch is a highly sensitive, non-directional trigger that detects vibration or motion and immediately breaks an electrical circuit, offering reliable, low-cost shock detection for countless electronic projects. This popular tilt and vibration switch operates in a Normally Closed (NC) configuration, meaning the two leads are connected (LOW resistance) when the device is at rest; any movement, impact, or tilting motion exceeding its threshold will momentarily open the circuit (HIGH resistance). Designers frequently select the SW-420 for its compact size, simple digital output, and high durability, making it an excellent component for anti-theft systems, safety alarms, and automated movement controls.

Key Features:

• Normally Closed (NC) Operation: The circuit remains closed (conducting) in the static, resting state, and opens momentarily when vibration or movement is detected.
• High Sensitivity: This sensor quickly reacts to even minor vibration, shock, or tilting motion, ensuring a swift trigger response.
• Digital Output: Providing a simple ON/OFF (Closed/Open) signal, the switch integrates effortlessly with microcontrollers like Arduino, Raspberry Pi, and PIC microchips.
• Non-Directional Trigger: The switch can detect movement from any 360° angle, providing comprehensive coverage without specific orientation requirements.
• Hermetically Sealed: The construction protects the internal moving parts from dust, moisture, and oxidation, ensuring long-term reliability.

Technical Specifications:

• Switch Type: Non-Directional Vibration/Shock Sensor
• Default State: Normally Closed (NC) – Closed when stationary.
• Maximum Current Capacity: 20 mA (DC)
• Maximum Voltage Rating: 12 V_DC
• Operating Temperature Range: −40°C to +80°C
• Insulation Resistance: ≥ 10 MΩ
• Switch Resistance (Closed): ≤ 10 Ω (Typically 1 Ω)
• Trigger Life Expectancy: ≥ 200,000 cycles

Mechanical Specifications:

• Package Style: Cylindrical (Radial Leads)
• Switch Material: High-Sensitivity Conductive Elements
• Housing Material: Copper/Nickel Plated Metal Shell
• Contact Bounce Time: ≤ 5 ms (Milliseconds)
• Shock Resistance: Rated for high mechanical endurance in impact-prone environments.

Dimensions:

• Body Diameter: ≈ 4.5 mm
• Body Length: ≈ 11.0 mm
• Lead Length: ≈ 10.0 mm (Each)
• Lead Spacing: Compatible with standard 2.54 mm pitch proto-boards (when leads are bent).
• Weight: Ultra-lightweight at ≈ 0.2 g.

Pinout and Wiring:

• Pin 1 (Input/Output): Connect one pin to the digital input pin on your microcontroller. Use a pull-up resistor (typically 10 kΩ) to V_CC.
• Pin 2 (Output/Input): Connect the second pin to GND (or to V_CC if using an external pull-down resistor).
• Wiring Note: In the NC configuration with a pull-up resistor, the digital pin reads LOW (GND) when static and momentarily reads HIGH (V_CC) when vibration opens the switch.

Datasheet Reference:

• Download SW-420 Vibration Switch Datasheet

Commonly Used in:

• Security Systems: Used as anti-theft triggers in doors, windows, and vehicles.
• Smart Home Devices: Integrated into smart locks and movement-sensing gadgets.
• Portable Electronics: Detecting accidental drops or impacts in handheld tools and devices.

Applications:

• Bike/Motorcycle Alarms: Triggering a loud siren upon unauthorized movement or tampering.
• Automated Lighting: Turning on lights based on a physical tap or knock.
• Toy and Game Development: Creating simple game inputs or interactive responses based on shaking or tilting.
• Seismic Monitoring: Providing a low-cost, basic trigger for high-vibration events.

Equivalent Models:

• SW-18015P / SW-18010P: Similar miniature spring-type vibration switches, often used when an NO (Normally Open) configuration is preferred.
• SW-520D: A similar model often found in tilt or rolling ball sensor categories, offering a comparable NC function but with less sensitivity to fine vibration.
• Various Unbranded NC Vibration Switches: Many manufacturers produce a functionally identical product under various internal part numbers due to the standardized cylindrical design.

Package Includes:

• 1 x SW-420 Normally Closed Vibration Sensor Switch