Inductive proximity sensor NPN NO LJ12A3-4-Z/BX 6-36V for 3D printers

Inductive proximity sensor NPN NO LJ12A3-4-Z/BX

The inductive sensor LJ12A3-4-Z/BX is a precise device with high distance measurement accuracy. It features an NPN NO output configuration. The sensor supply voltage is 6-36V DC, and its maximum detection range is 4 mm. The module is an excellent choice for DIY projects, 3D printers, and automation. The product is compatible with popular platforms: for Arduino, for ESP8266, for ESP32, for Raspberry Pi.

Operating principle and wiring

When an NPN sensor detects a metal object, it drives the output low (0V). NO (Normally Open) configuration means the output remains inactive when no object is within range. Detection of a metal surface at up to 4 mm is indicated by a low output state and illumination of the built-in indicator LED.

Wire colours:

• Brown - power (6-36V)
• Blue - power (ground)
• Black - normally open NO output

Key technical specifications

• Supply voltage: 6 - 36V DC
• Detection range: 0 - 4 mm
• Maximum operating current: 0.3 A
• Sensor housing: M12 thread
• Sensor type: inductive
• Output type: NPN NO (Normally Open)
• Indication: built-in LED on the underside
• Dimensions: total length 62 mm, threaded section 40 mm, sensing face 5 mm
• Cable: 3-wire, approx. 100 cm long

Example applications

• Detecting bed or print head position in 3D printers and CNC machines
• Counting metal parts on production lines
• Industrial automation and robotics systems
• Limit switches in various mechanical devices
• Projects with microcontrollers (for Arduino, for ESP32, for ESP8266, for Raspberry Pi)

Benefits

• High reliability and precision thanks to contactless detection
• Wide supply voltage range (6-36V) for easy integration with many systems
• Easy mounting using standard M12 thread and included nuts
• Visual status indication via the built-in indicator LED
• Resistance to mechanical wear and long-term, trouble-free operation