SN04-N NPN NO Distance Proximity Sensor Switch Module
SN04-N Inductive Proximity Sensor
Contactless Industrial Metal Detection
Infographic Overview
SN04-N PROXIMITY SENSOR h > is an inductive proximity sensor used to detect metal objects without physical contact.
It is widely used in:
CNC machines
Robotics
Industrial automation
Detects only metal (iron/steel) objects
Working Principle
Sensor Coil Magnetic Field Generated'Metal Object Approaches'Eddy Currents Form in Metal'Magnetic Field Disturbs'Sensor Output Changes (ON)
When metal comes near:
Magnetic field is disturbed
Internal oscillator stops
Output signal is triggered
Wire Configuration (3-Wire)
Brown VCC (+1030V)Blue GNDBlack Output Signal (NPN)
Standard industrial wiring
Output Type (Importted ON
Works like a switch to ground Needs pull-up resistor for microcontrollers
Key Features
Non-contact metal detection High accuracy & repeatability Fast response (~500Hz) LED indicator for status Dust, oil, and water resistant (IP67) Reverse polarity & short-circuit protection
Technical Specifications
Parameter | Value |
Detection Distance | ~4 mm |
Voltage Range | 1030V DC |
Output Type | NPN NO |
Output Current | 300 mA |
Response Frequency | ~500 Hz |
Sensing Target | Metal only |
Cable Length | ~11.5 m |
How Output WoF (0) Metal detected ON (1)
LED turns ON when object detected
Applications
CNC machine end-stop detection 3D printer auto bed leveling Conveyor object counting Robotics position sensing Industrial automation systems
Arduino / Microcontroller Interface
Important:
Sensor outputs 1030V signal
Microcontrollers use 5V / 3.3V
Solution:
Use:
Voltage divider OR
Optocoupler OR
Transistor interface
Example (Safe Interface)
Sensor Output Resistor Divider Arduino Pin
Advantages
No physical wear Works in harsh environments High durher voltage (not directly 5V friendly) Affected by metal type & size
Pro Tips
Use iron/steel target for best accuracy Keep sensing face clean Avoid wiring noise (use shielding) Always use proper voltage protection with Arduino
Summary
The SN04-N NPN NO Proximity Sensor is a robust industrial-grade sensor ideal for:
Metal detection Automation systems CNC & robotics projects
It's a perfect replacement for