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Comment by kovac | Hacker News Reader

Love it! Any idea how long the display can last? I've been playing around with e-paper (nothing as impressive as this!) dashboards. I use Waveshare displays that has a max of 1 million refresh cycles. The display you've used seems more capable.

My own humble e-paper projects:

https://www.asciimx.com/projects/e-reader/ https://www.asciimx.com/projects/etlas/

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Hi, I'm Eric, Evertop's creator. The screen has a refresh rate of about 350ms, or almost 3 times per second. Of course the device is smart enough to not refresh the screen unless there's a change in displayed content, so it's not like it's actually always refreshing 3 times per second. I've been using the same screen for probably an average of 1-2 hours per day for a little over two years, and can see little or no difference in the clarity of the text and graphics as compared to a brand new screen.

It's probably https://www.good-display.com/product/440.html which is also 1mil refresh cycles and a fast refresh time of 1.5sec - around 185 hours of screen updates, so ~3 months of 5hrs a day typing or a few years of e-reader style usage.

I can't really see a device like this getting used super heavily every day, so expecting it to still be usable from time to time for a few years seems reasonable to me.

For e-ink, does the refresh count include the entire screen or individual pixels?

From what I can tell, a partial refresh of the display (updating a smaller portion of the screen) performs less wear on the display than a full refresh, but it can still accumulate over time. Additionally some displays will require a full refresh after a certain number of partial refreshes to deal with ghosting.

Huh, interesting. I don't know anything about it, but my Kobo Libra has settings for how often to refresh the whole screen (e.g. every N pages, at the end of the chapter, etc.).

it does not matter in practice, let's say you do a full refresh once a second, it would take more than 11 days to do 1 million refreshes, if you do full refresh once a minute, it would take 2 years

Those numbers don't seem high, at all, for me. Typing would probably cause a refresh more often than every second and even if it's delayed to be once, every second, it's still only 11 days.

For the usage being discussed here, 1 million is extremely low. For its original intended usage, which might cause one to dozens of refreshes per day, it's more than it'll ever need.

For eink reader is more than enough, for digital typewriter eink is not good choice for display, there are high contrast lcd displays with in-pixel memory that can be used

I read an article from someone doing a similar project and if you don't do a full refresh every so often then you'll actually wear out the display faster (he burned one out real quick). It actually needs those full refreshes after so many partial updates.

I don't know about this display but I've tinkered a bit with Waveshare E-Ink, that has this disclaimer:

"For e-Paper displays that support partial refresh, please note that you cannot refresh them with the partial refresh mode all the time. After refreshing partially several times, you need to fully refresh EPD once. Otherwise, the display effect will be abnormal, which cannot be repaired!"

https://www.waveshare.com/wiki/1.54inch_e-Paper_Module_Manua...

That seems like a really short lifespan...? Like you can use it for a couple years, but only if you don't actually use it.

There's an obvious aesthetic draw to e-ink, but it seems like passive-matrix monochrome LCD (like the Playdate) would be similarly power-efficient (or better [1]), longer lasting, usable in full daylight, and with better refresh rates.

How good are the best monochrome LCD screens now? Like... most reflective background and feel the flattest? (The vertical offset between the liquid and the background always bugs me.) Playdate (a Sharp Memory LCD [2]) seems pretty good but surprisingly low contrast. I suppose because the liquid crystal still blocks light even when its off? (I'm unclear here)

Looks like the OLPC transflective LCD screens are actually manufactured now [3] (5" display for $50 [4], maybe 10" but I'm skeptical [5]). The overall OLPC design was actually pretty great [6], even if many of the components weren't so great; it would be cool to see that revisited by some hobbyist.

[1] https://electronics.stackexchange.com/a/403725

[2] https://www.adafruit.com/product/4694

[3] https://www.kingtechlcd.com/product-category/transflective-d...

[4] https://www.alibaba.com/product-detail/5-inch-transflective-...

[5] https://www.alibaba.com/product-detail/10-inch-1200-1600-Tra...

[6] https://en.wikipedia.org/wiki/OLPC_XO

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