Autonomous Sensor Monitoring in sub-µA Energy Modes
With the Low Energy Sensor Interface (LESENSE), the EFM32 microcontrollers are able to monitor a wide variety of sensors while continuously staying in energy saving deep sleep mode. Applications in need of wake on capacitive touch, sensing metallic objects or monitoring resistive sensors can be implemented with total consumption below 1.2 µA. The sensors that LESENSE can interface range from simple thermistors, inductive or capacitive devices, to more complex analog sensors. This paper will present three different measurement principles—capacitive, inductive and resistive—that can be implemented with a low energy sensor interface.