This is a small 96×64 graphical display from an old Nokia 1100 phone, controlled through bluetooth SPP by an Android phone.
The core of the smartwatch is an ATtiny2313 AVR cpu, which is serially interfaced to an HC-05 bluetooth SPP module. The whole system is powered by a small 3.7V lithium battery from a camera.
An Android application i developed, renders some text onto a monochromatic bitmap buffer, which is then transferred to the display.
With a baudrate of 9600 bits per second, the screen is updated in half a second.
The higher baudrate allowed with no errors with an 8MHz clock is 38400, it fills the screen in less than 200ms.
