Proximity sensor that detects nearby metal, including aluminum foil; a great solution for heated bed calibration.
The Inductive Proximity Sensor LJ12A3-4-Z/BX 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 inductive proximity 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 LJ12A3-4-Z/BX 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
Save time messing with springs and screws on your print bed. Run the Auto-level procedure before every print or just one time for each start-up of the printer. Less issues related to un-level print beds like parts coming up on one corner and nozzles jamming because the print started too close.
Note: To set up your printer for auto-leveling, you need to update your firmware and make a mount for your Inductive Proximity Switch.
Specifications and Features :
- Product Name : Inductive Proximity Switch.
- Model : LJ12A3-4-Z/AX.
- Theory : Inductive Sensor.
- Wire Type : 3 Wire Type (Brown, Blue, Black).
- Switch Appearance Type : Cylinder Type, Metal Shell.
- Output Type : NPN NC.
- Detecting Distance : 4 mm.
- Supply Voltage : DC 6 V-36 V.
- Output Current : 300mA.
- Detect Object : Iron.
- Column Sensor Diameter : 10.4mm/0.4″.
- Thread Diameter : 12mm/0.5″.
- Total Size : 66 x 21 mm/ 2.6” x 0.8” (L x Max.D).
- Cable Length : 1.16m/35.7”.
- External Material : Plastic, Metal.
- Net Weight : 43 gm.
- Color : Silver Tone, Orange,Gray.
Attachments and Links :
Home switch wiring example using Inductive Proximity Sensor Detection Switch NPN DC6-36V 4mm Normally Open proximity switch LJ12A3-4-Z/BX
Tube Type Inductive Proximity Sensor Detection Switch NPN DC6-36V
Package Includes :
1 x Inductive Proximity Sensor LJ12A3-4-Z/BX