Embodiments of the present disclosure provide techniques and configurations for a wearable device with power state control. In one instance, the device a functional module to operate in a first power state or in a second power state that is different from the first power state; a power source coupled with the functional module to provide operational power to the functional module; and a power state control module coupled with the functional module, to cause the functional module to transition from the first power state to the second power state in response to an input. The power state control module may comprise a power generating device to generate power responsive to the input, independent of the power source, and in response to the generated power, cause the functional module to transition from the first power state to the second power state. Other embodiments may be described and/or claimed.