SparkFun Thing Plus - RP2350 Brand_Espressif the creation of the Adafruit

the creation of the Adafruit RP2040 Prop-Maker Feather: an all-in-one combination of the Feather RP2040 with a Prop-Maker FeatherWing with a few tweaks based on feedback from expert prop-builders

Contactless Interface Based on ISO/IEC 15693

If a 1 Mega-ohm resistor is placed across the two terminals you will see the current converted into a voltage that can be read by an analog-to-digital converter (ADC)

but better yet just grab a 4-JST cable set - then check the LED modules to see which way is the input (there's arrows showing the data direction)

And last up

SparkFun Thing Plus - RP2350 Brand_Espressif the creation of the AdafruitThe SparkFun Thing Plus RP2350 is a dynamic and powerful wireless development platform in the Thing Plus form factor. Built around the RP2350 microcontroller from Raspberry Pi, this board includes their radio module for single band 2. 4 GHz WiFi 4 (802. 11n) and Bluetooth 5. 2 along with standard hardware components found on all Thing Plus Boards. This includes on board Lithium Ion (LiPo) battery charging and fuel gauge circuits, SD card socket, Qwiic