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RAK12029 WisBlock Inductive Sensor Module Datasheet

Overview​

Figure 2700: RAK12029 WisBlock Inductive Sensor Module

Description​

RAK12029 is a metal detection sensor module based on the LDC1614 from Texas Instruments. The LDC1614 is an inductance-to-digital converter (LDC) that measures the oscillation frequency of four LC resonators. It outputs a digital value, that is, proportional to frequency, with 28 bits of measurement resolution. With this digital value, you can detect the presence of metallic objects.

Features​

  • Metal detection module
  • Sensing coils up to four channels
  • 28-bit LDC
  • Immunity to DC magnetic fields and magnets
  • 3.3 V Power supply
  • Operating Current: 0.2 uA to 2.1 mA
  • Chipset: Texas Instruments LDC1614
  • Module size: 25 x 35 mm

Specifications​

Overview​

Mounting​

The RAK12029 WisBlock Inductive Sensor Module can be mounted to the IO slot of the WisBlock Base board. Figure 2 shows the mounting mechanism of the RAK12029 on a WisBlock Base module.

Figure 2701: RAK12029 WisBlock Inductive Sensor mounting

Hardware​

The hardware specification is categorized into five parts. It shows the chipset of the module and discusses the pinouts and their corresponding functions and diagrams. It also covers the electrical and mechanical characteristics that include the tabular data of the functionalities and standard values of the RAK12029 WisBlock Inductive Sensor Module.

Chipset​

VendorPart number
Texas InstrumentsLDC1614

Pin Definition​

The RAK12029 WisBlock Inductive Sensor comprises a standard WisBlock connector. The WisBlock connector allows the RAK12029 module to be mounted to a WisBlock Base board. The pin order of the connector and the pinout definition is shown in Figure 3.

NOTE
  • I2C related pin, 3V3_S, and GND are connected to WisIO connector.
  • SD (WB_IO5) is shutdown mode pin. High input voltage configures the module to shutdown mode.
  • INT (WB_IO6) is a configurable interrupt output pin from the LDC1614.
Figure 2702: RAK12029 Pinout

Electrical Characteristics​

Recommended Operating Conditions​
SymbolDescriptionConditionMin.Nom.Max.Unit
3V3_SSupply voltageInput voltage must within this range2.73.33.6V
IDDSupply currentNormal-2.1-mA
IDDSLSupply currentSleep mode supply current-3560uA
ISDSupply currentShutdown mode supply current-0.21uA

Mechanical Characteristics​

Board Dimensions​

Figure 4 shows the dimensions and the mechanical drawing of the RAK12029 module.

Figure 2703: RAK12029 mechanical drawing
WisConnector PCB Layout​
Figure 2704: WisConnector PCB footprint and recommendations

Schematic Diagram​

Power Supply Circuit​

Figure 6 shows the RAK12029 power supply circuit.

  • 3V3_S supply voltage comes from the WisBlock Base board (max voltage: 3.6 V).
  • VDD is the supply voltage going to the module (max voltage: 3.6 V).
Figure 2705: RAK12029 power supply
Inductive Sensor Circuit​

Figure 7 shows the inductive sensor circuit.

  • U1 is the LDC1614 Inductance to Digital Converter (LDC) chip.
  • P1, P2, P3, and P4 are the connectors for the four sensing coils. The four channels are independent of each other. You can choose how many coils to connect. About the coil, RAK provides one type of coil as an accessory. If you need to design your own coil, you can read the LDC Reference Coils User’s Guide from Texas Instruments.
Figure 2706: RAK12029 inductive sensor circuit
I2C Circuit​

The I2C interface of the RAK12029 is shown in Figure 8. The pull-up resistors are not populated because the needed pull-up resistors are already in the WisBlock Base board.

Figure 2707: I2C interface of the RAK12029
I2C Address​

The I2C address of RAK12029 can be configured via resistor jumpers as shown in Figure 9.

Figure 2708: RAK12029 I2C address
Clock Circuit​

RAK12029 has an optional clock oscillator to provide an external 40MHz clock source to the module. RAK12029 uses an internal crystal oscillator as default. The schematic diagram is shown in Figure 10.

Figure 2709: Clock circuit connection