NPN LJ12A3-4-Z/BX Inductive Proximity Sensor

Features:

• Detection Distance: 4mm
• Voltage: DC 6-36V
• Polarity: NPN
• Dimention: 12 x 50mm
• Black or Gray wire

Product description

• Proximity sensor that detects nearby metal, including aluminum foil; a great solution for heated bed calibration.
• The LJ12A3-4-Z/BX proximity sensor will detect large metal fields at 4mm distance with great precision.
• This allows you to accurately measure the distance to an (aluminum) heated bed for example.
• If you are using a glass plate as your print surface, you can use aluminum foil right below the glass, which will also be detected by the sensor (mirrors however are not detected).
• The sensor is equipped with a small red detection LED, indicating a nearby object.
• The sensor has an M12 threading and includes a nut for easy mounting to your 3D printer or CNC machine.
• The LJ12A3 is a NPN Normally Open (NO) type of proximity sensor, which means when nothing is detected the resistance on the black wire is high.
• Upon detection the resistance will be low and connects to ground. Use the internal pull-up on your Arduino.
• Most modern 3D printer firmwares have some sort of auto bed leveling procedure available, but you will need to enable it.
• You can use this sensor as the z_min_endstop for example, replacing your current end stop. Most firmware will also use the min endstop as a probe, but some allow a separate probe to be defined.
• This sensor operates at 6-36V, so as the signal voltage is the same as the input voltage, also the signal will be 6-36V.
• You will need to down-convert the voltage to acceptable level for your electronics. Put a 10K resistor between the black signal line and your 5V electronics input to avoid damage.