I tripped over this brochure in my travels. My eye was drawn to the bit that said that the update voltage was 0.5 micro-amps per cm2, and that it runs off 5V. Maybe this is outside the realm of possibility, but I love the idea that it draws no current when it is not updating. Now this is a 33-segment display, and not a bitmap, but I assume you can have whatever you want if you pay enough.
http://media.digikey.com/pdf/Data%20Sheets/BNS%20Solutions%20PDFs/SC009221_Br.pdf
I’d quite like to futz around with a Dev Kit to see how much power it draws in practice.
DigiKey has one for $70
http://www.digikey.com/product-search/en/programmers-development-systems/eval-and-demo-boards-and-kits/2622039?k=BNS
Mik Lamming says:
I was thinking that the display could use the same idea as the ranger – it has to wait until the supercap is charged enough to let it do it's job. A simple count of the pixels to be changed should provide a good estimate.
David Carkeek says:
If there is room for it then we could use it. The 5V requirement would take extra effort but there's a possibility the voltage could be drawn off the supercap (if we use that scheme in the power supply) since it would be charged to about 5.25V.