Abstract: The present disclosure presents self-powered Bluetooth backscatter sensor systems and related methods. One such system comprises a wearable sensor device having communication circuitry, sensor circuitry, and at least one sweat-activated cell for powering the sensor circuitry; and a transmitter device having an interface for receiving power supplied from a power interface of an electronic communication device having a communication receiver. The transmitter device is configured to be powered by the electronic communication device via the power interface and transmit a continuous wave signal, such that the communication circuitry is configured to receive the continuous wave signal. The sensor circuitry is configured to acquire sensor data; and the communication circuitry is configured to modulate the sensor data onto the received continuous wave signal and transmit the modulated signal as a backscattered signal.