Abstract: Various embodiments of the invention allow for improving measurement accuracy of monitoring devices, for example, to accurately determine speed from motion data measured by an accelerometer. In certain embodiments, this is accomplished by applying a classification process that resembles a random forest classification to recorded sample data to detect similarities to features associated with data for a known speed type, classifying sample data into speed types, and finally averaging the speed types to obtain a high accuracy estimate value for a final speed.

Abstract: Described herein are systems and methods for low-power voltage sensor circuits and current sensor circuits using an optically coupled isolator. In various embodiments, opto-couplers replace bulky transformers that are used in common designs. In embodiments, an optically coupled isolator is used as a power gate to reduce power consumption. Further power savings may be obtained by selecting appropriate phototransistors and adjustable bias resistors to set the forward current of a photodiode as small as functionally possible to reduce battery discharge while providing sufficient gain for the optical transistor. In certain embodiments, the bias voltage point may be chosen to be at the turn-on voltage of the photodiode. In embodiments, power consumption of the voltage and current sensors may be adjusted by adjusting the frequency of a power-gating control signal, which may be controlled by a microcontroller.