Braille Information Reader Device
From Hackstrich
The Braille Information Reader Device (BIRD) will be a braille-outputting e-book reader device. The device itself will be a small module that plugs into a commercially available braille display (the initial and probably only target will be the PACmate20 Braille Display because that's what I use, and they're way too expensive to justify me getting more to port it), and accepts MicroSD cards with TXT or BRF files to read.
Project Status
Prototype stack assembled, code writing in progress. Currently braille display driver PoC is working, and reading files from MicroSD cards works (separately). Schematic, board layout, and BOM complete for actual PCB (using a PIC32).
Prototype Stack
The stack of boards for the prototype BIRD will be:
- Adafruit Proto Shield with MicroSD socket breakout and resistor voltage divider
- Circuits@Home USB Host Shield (which has been modified with stack-through headers)
- Arduino Duemilanove
Design Overview/Ideas
- MCU needs to support USB On-The-Go so it can act as a host (to plug the display in) or a device (to connect to a PC to load in books)
- The PIC32MX575 looks good for this and will be used in the first revision
- Board needs to supply USB power when acting as a host
- 500mA would be best, as different displays will use different amounts of power, and I don't want a hardware limit there
- LiPoly battery for good life and minimal weight
- Charging and fuel gauging will be built in (even though the latter is a PITA to implement)
- Two regulators will be needed, one for 3.3v (BIRD) and one for 5v (USB power for display)
- The latter needs to be switchable
