Wearable personal digital device with changeable bendable battery and expandable display used as standalone electronic payment card

A wearable personal digital device, the device comprising:

• a processor;
• a memory unit communicatively coupled to the processor;
• a basic display device, permanently mounted to the device and communicatively coupled to the processor, the basic display device having a first display space;
• a detachable display device, communicatively coupled to the processor, the detachable display device having a second display space and configured to expand the first display space by operably coupling the second display space with the first display space;
• a credit card-sized display device having a magnetic stripe and integrated circuit (IC) card reader, wherein the credit card-sized display device is configured to wirelessly couple to a front, rear, left side or right side of the basic display device;
• a camera communicatively coupled to the processor;
• a display projector communicatively coupled to the processor;
• a communication circuit communicatively coupled to the processor and configured to connect to a wireless network and to communicate with one or more external devices;
• a swipe card reader communicatively coupled to the processor and configured to read data of a payment card, the data being transmitted to the processor;
• one or more biometric sensors to sense biometric parameters of a user, the biometric parameters being stored to the memory and processed by the processor to receive historical biometric data;
• one or more accelerometers to track activity of the user, the activity of the user including calories burned, sleep quality, breaths per minute, snoring breaks, steps walked, and distance walked;
• a housing adapted to enclose at least the processor, the memory unit, the basic display device, the detachable display device, the camera, the display projector, and the communication circuit, wherein the housing is water-proof and dust-proof;
• and
• a band adapted to secure the device on a human body, the human body including a wrist, an arm, a neck, a head, a leg, a waist, an ear, a finger, and any other part of the human body, wherein the band is adapted to secure the device under, within or on clothing, wherein the band includes a rechargeable battery configured to power the device,
• wherein the device comprises a smart watch.