Subject: General Tech | April 3, 2013 - 01:43 PM | Tim Verry
Tagged: wireless display, Raspberry Pi, paperwhite, mobile, kindle, e-ink
The Raspberry Pi makes for a cheap and low power media PC, file server, or desktop but the lack of a display means that it is not very portable. Recently a hack was posted online by Max Ogden that enables the Rasbperry Pi to be used on the go by pairing it with an Amazon Kindle and its e-ink display. His wireless display setup was actually based on a previous hack that allowed the Pi to be paired with the 3rd-generation Kindle. Ogden's hack takes things a step further by supporting the latest Paperwhite versions as well as no longer requirig a wired connnection between the display and the Raspberry Pi.
By loading the Raspberry Pi with Raspian Linux and adding a terminal emulator to the Kindle, the Kindle connects to the Pi over an SSH session where the Pi console and any keyboard input can be seen on the Kindle's e-ink display. The hardware needed to make the setup work includes a Wi-Fi hotspot, a Wi-Fi USB NIC, The Raspberry Pi, a supported Kindle, and a battery pack with enough juice to power everything. A wired or wireless keyboard and Wi-Fi dongle can be added to the Raspberry Pi Model B, bu Model A users will need to add a USB hub as the $25 model only supports a single USB port on the device itself.
Max Ogden shows off his new portable battery-powered Raspberry Pi with wireless e-ink display.
There are some limitations to this setup. One is a bit of latency between typing and seeing the characters appear on the screen due to the low refresh rate inherent in e-ink displays and the wireless connection. Ogden estimates that this delay is around 200ms, and is noticeably but bearable while typing. The other major limitation is that the display can currently only be used to display the Pi console, and not the GUI of Raspian. For writing code or articles, you could get by with a command-line text editor like nano or vi--at the very least it would be a distraction-free writing environment as you could not procrastinate and browse Reddit or watch videos even if you wanted to (heh).
If you are interested in setting up your own wireless Raspberry Pi display, you should check out Ogdens blog for a list of recommended hardware as well as Rod Vagg's tutorial on configuring the Kindle Paperwhite with the correct software.
This is one of the more-useful Raspberry Pi hacks that I've seen so far. Hopefully, a future hack will come along that will also allow one of these e-ink devices to display the GUI desktop environment and not just the terminal.