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I made an e-ink clock, but ultimately found it unsuitable for my desk. The problem is that when the display refreshes, it switches from white to black and back
by jrockway 7y ago
I made an e-ink clock, but ultimately found it unsuitable for my desk. The problem is that when the display refreshes, it switches from white to black and back to white, and all this activity in the corner of your eye ends up being quite distracting. You are guaranteed to look at it whenever it changes, making it worse than a notification on your phone in terms of interruption. That might be the right thing for "you have a meeting now!" (you're interrupted anyway), but it's not great for passive information like the time.
I am told that with some amount of hacking and a supportive chipset/vendor, you can avoid most of this without reducing the lifetime of the display with the right calibration constants for the device... but nobody seems to have open-sourced anything like this and even places like Adafruit don't provide proper datasheets.
- peteradio 7y agoCan you elaborate on what causes issues with lifetime? What kind of constants are involved in e-ink displays?
- jrockway 7y agoI didn't design these things, so all I know is that the datasheet says the lifetime will be reduced if you update it more than once every five minutes. A clock with a minutes display exceeds that by 5x. (And indeed, the display I used did break! I have no idea why, but it just stopped updating one day.) Ben explains some of the constants that can be tweaked here: https://www.youtube.com/watch?v=MsbiO8EAsGw https://www.youtube.com/watch?v=MsbiO8EAsGw
- brettcvz 7y agoI can provide some context here - from my experimentation, after 10 partial updates the contrast is notably worse, but doing a full screen refresh resets things sufficiently that the screen looks sharp again. To reduce degradations further, whenever UpNext boots it does a cycle of 10 full screen refreshes - overkill certainly, but I think of this as the “cleaning cycle.” If the screen ever starts to fade, I power cycle it, and it’s fine for a long time. I’ve been running it continuously like this for 2 years now, and while the screen is a bit less sharp than it was originally, it’s still in good shape - the photos in the article are from this week.
- blueboo 7y agoMaybe it can be incorporated into the design: refresh as a kind of 5m warning before your next meeting. I’ve certainly enough meetings not to exhaust ten refreshes before the next head’s up flash...
- dpcx 7y agoThe author of the article discusses exactly this and how they got around it. Seems that some updates have been made to drivers to only do partial screen refreshes.
- crusso 7y agoThe author reduced the frequency of full refreshes, but did not eliminate them. The problem will still occur, just less often.
- brettcvz 7y agoYou are correct - because I have a clock on the screen, UpNext does a full screen refresh about every 10 minutes. I thought this would bother me so did some explorations of a UI without the clock, but in practice I don’t notice the flashing, and I like having the clock.
- wffurr 7y agoA clock seems like a poor choice for an e-ink display. It's going to update once a minute or whatever interval you pick. A calendar will only update when your calendar events pass, which at least for my usage tends to be limited to 30 minute intervals and generally only a few times a day.
- andai 7y agoFor a clock you would be better off with a transflective LCD, if you can find one. There's a couple different variants and they're generally very small, but have high refresh rate and no ghosting.