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Valve open source the Steam Machine e-ink screen so you can make your own
(www.gamingonlinux.com)
This is a most excellent place for technology news and articles.
Where did you see the battery? I don't see one mentioned anywhere
here
For some reason the battery isn't mentioned in the parts list but it's shown in the video and mentioned in the instructions. Would be pretty easy to power the esp feather with a dcdc converter off of a USB port or something assuming it doesn't take 5v directly