Inductive Metal Detection Sensor (4-Channel) RAKwireless RAK12029 (TI LDC1614)

RAKwireless RAK12029 is a WisBlock module for contactless metal presence detection and inductive proximity/position sensing using coils. At its core is the TI LDC1614, an inductance-to-digital converter (LDC) that measures the oscillation frequency of up to four LC resonators. The device converts frequency into a 28-bit digital measurement value, making it easy to process in firmware and integrate into sensing logic.

Unlike simple on/off inductive switches, an LDC-based setup can provide higher-resolution readings that support more nuanced detection and repeatable thresholds—depending on coil geometry and the mechanical target. A practical advantage in industrial environments is the stated immunity to DC magnetic fields and magnets, which helps in systems where magnets, motors, or magnetic fixtures are present.

Common real-world use cases:

Metal presence / proximity detection in automation (part present, end-stop detection, mechanism position).

Hidden interface sensing, where inductive sensing works behind non-metal covers while using a metal target.

Position and motion monitoring on metal components where optical sensors may fail due to dust, oil, or condensation.

Multi-point sensing, using four channels for multiple coils/zones within one system.

The module includes four wireless coil patches to get you started quickly with prototypes. It operates on 3.3 V and lists 0.2 µA to 2.1 mA operating current depending on mode. Board size is 25 × 35 mm.