PIP-Watch (Personal Information Panel) will be an open-source smart watch with an ePaper (EPD) display, a bluetooth adapter, and a Li-Ion.
This project was created on 05/18/2014 and last updated 5 days ago.
In my previous homebrew projects I did not use any operating system in the embedded processors. Software was programmed on a bare-metal hardware. In my Talking Clock project I created a simple cooperative event-processing abstraction layer, but it was very limited.
In PIP-Watch there are multiple independent tasks that should execute concurrently and exchange information at specific points. These are: Bluetooth modem task, Display drawing task, and Battery monitoring task.
GDE021A1 is a graphics display with a resolution 172x72 pixels, each pixel is 2 bits deep (4 shades of grey). The display has an internal controller SSD1606 with a framebuffer. The framebuffer size is 172*72*2/8=3096 Bytes. When the display is powered up, the system processor sends initialization sequence that first sets up controller's internal registers (the controller SSD1606 is fairly generic) and then sends new framebuffer content. The display controller then autonomously pushes the framebuffer contents to the physical screen.
The display controller can be configured to orient the framebuffer almost any way. I configured it into a landscape mode, with the X-axis going right and the Y-axis down, as shown on the photo.
Today I have managed to get the GDE021A1 ePaper display (EPD) working! I used my minimal EPD-Driver board, which implements a flat-flex cable connector and a booster circuit for the display. The booster generates high voltages needed for display operation (around +-25V). The display is driven by STM32F101 Cortex-M3 CPU, mounted on a universal PCB. The picture below depicts my workbench setup:
Great Project - thanks for entering PIP-Watch in The Hackaday Prize! Less power to the display means more mAh available for other stuff - like radios to connect! Try to get a few images uploaded when you can - every little bit helps you on the road to winning!
Search for GDE021A1 on ebay.com. I got mine in April for $14, however, currently they sell it for $45, which is plain ridiculous :-( Or try contacting the manufacturer: http://www.good-display.com/products_detail/&productId=07992b88-6ac5-4a0e-ba84-d7cadcd55ebe.html