This is too cool. Today, after much anticipation, Texas Instruments announced Inductance-to-Digital Converter sensing technology, the LDC1000, that is both contactless and magnet-free. Coils and springs are used as inductive sensors of position, motion, and composition of a metal or conductive target.
The focus of the technology is on applications that need to detect moving parts -- prevalent in such sectors as industrial, automotive, medical, white goods, and consumer. These applications typically use Hall sensors, which require expensive magnets, and that have inherent drift challenges over time and temperature.
Editor's Note: See a more detailed description of the inductance-to-digital converter on EDN: Texas Instruments inductance to digital converter (LDC): Necessity breeds invention.
Inductive sensing works by establishing a resonant circuit that uses the inductance of a coil and capacitor. Once a metal object is sensed, the resonant frequency is altered.
The LDC1000 is housed in a 16-pin 4mm x 5mm package. There will be a separate automotive qualified version. There's an available evaluation board and a new WEBENCH Inductive Sensing design tool.
Naturally, it will be less expensive to use, but it's also designed to improve resolution and reliability, and provide more flexibility. Given its size and packaging, it will be easy to integrate where large PCBs just can't be used. It also supports pressed foil and conductive ink targets, which should open the floodgates for new and creative design. This solution is immune to non-conductive interference.
Samples, an EVB, the data sheet, and application notes are available.
The LDC1000EVM EVB includes an MSP430F5528 MCU and can be purchased for $29.00.