Some examples include a secure low-power sensor platform able to be used for activity monitoring or other purposes. For instance, a sensor system may sense sparse signals using compressed sensing. As one example, compressed sensing may be used to obtain sparse signals from analog sensor signals received from one or more sensors. The data obtained by compressed sensing may be sent subsequently to a computing device to reconstruct the sensor signal. Examples herein enable lower power usage, lower cost, and lower weight than conventional devices, while also enabling processing advantages, such as less overall data to process and lower data storage utilization.