The Open Book — An Open, Feather-Compatible eBook!
Our world is reliant upon written information. Even in this digital age, eBook products (Kindle, Kobo, et al) are commonplace items in…
Our world is reliant upon written information. Even in this digital age, eBook products (Kindle, Kobo, et al) are commonplace items in most households.
Every brand name reader has a common pitfall though, and that is the (generally) closed ecosystem from which the device sources its content.
Joey Castillo recognizes this issue, and has embarked upon the Open Book, a project set to overcome the limitations enforced by the various platforms.
In its current incarnation, the Open Book is realized as an Adafruit-compatible FeatherWing add-on. Recently, the Feather has become the de facto form factor for new MCU boards, and the supporting add-on boards that go with them. It is almost rare to see a shield laid out for the Arduino R3 form factor these days, so Castillo’s choice to go with a Feather-compatible board makes a lot of sense; you can almost guarantee you can drive the board with your favorite flavor of MCU!
There is a huge amount of functionality on this board, and the PCB itself is a beautiful example of what “self documenting” hardware should look like. Every circuit block is described in the space surrounding it through liberal use of silkscreen labelling — you probably won’t need to reach for the documentation for this board while prototyping, as even display FPC pinout is included right there on the board.
However, the project is far more than just a EPD display breakout board. Castillo has included a good range of peripherals on current revision of his pocket-sized prototype:
- An arrangement of tactile switch buttons for control, interfaced using an I2C port expander, to free up some Feather GPIO pins for other uses. A hardware “enable” switch supports low power operation.
- A SPI Flash comes in handy when the MCU board lacks enough of its own storage.
- A SPI SRAM IC, which can serve as a buffer memory for the EPD, when using the Adafruit EPD Library.
- A headphone jack and associated circuitry, allowing the user to incorporate audio into their project.
- Speaking of audio, an SD card slot provides even more storage capacity, which is handy for those larger file types.
- A suite of JST-PH ports provide a robust interface to the remaining I/O of the Feather.
If you want to really make the most of the EPD display, and all those fun peripherals, Castillo recommends an M4 Feather, as that will have enough horsepower to handle everything. That board also supports CircuitPython, which can be seen running below.
The project is open source, and the revision B boards featured here are available to download from Castillo’s GitHub project page. You can order the PCBs directly from OSHPark, and build your own!
Revision C is already in the works, and should include an ATSAMD51 processor on the board itself. This is the same powerful chip as used on the Adafruit Grand Central M4 boards, so we hope to see some really slick builds using this hardware!