In one aspect, this disclosure is directed to an activity tracking device having a size and shape adapted for physical coupling with a user. The activity tracking device may include one or more sensors to generate sensor data. For example, the sensor data can include activity and/or biometric sensor data related to the user and/or environmental sensor data related to an environment around the user. The activity tracking device may also include an identification tag including identification data that includes information about actions and/or operations associated with the particular activity tracking device. The activity tracking device also can include an identification tag transmitter, electrically coupled with the identification tag, to wirelessly transmit the identification data, according to a communication protocol, to a wireless reader responsive to coming within a proximity of the wireless reader. The wireless reader can perform, or cause a processing device to perform, the actions and/or operations.