EEVblog #1241 - Power Up Display Counter Project - Part 1

[ipscell]

Found this e-ink display on Taobao. Claimed to work down to 2.3V. I think this could be better compared to a segment because it allows smaller size and easier MCU interfacing.
https://item.taobao.com/item.htm?spm=a230r.1.14.130.56721a21xd94y2&id=588912154396&ns=1&abbucket=20#detail

Search query: 电子墨显示

Also what do you think about mechanical counters like this one? Just plug a motor into it and make it stop after 1 revolution. You can even 3D print these and get any size and digit number.

[westfw]

Bistable ChLCD. Seems like a good alternative to e-ink and memory LCD.

Whatever happened to cholesteric liquid crystal displays, anyway?  (these will retain an image with zero power; exactly the sort of thing Dave is looking for.)  I remember "Kent Displays" showing up at trade shows touting the technology, and it's "low cost manufacturing on flexible substrates", but Kent seems to have become a consumer products company ("BoogieBoard"), and it doesn't look like the tech has passed on to anyone else (or at least, it hasn't shown up in the mass market) :-(IIRC, driving the chLCD was a bit problematic, but I didn't think it was worse than ePaper.  I recall several "simple" displays being sold (batter gauge with a couple of digits and a bar graph, etc.)

[Fungus]

Also what do you think about mechanical counters like this one? Just plug a motor into it and make it stop after 1 revolution. You can even 3D print these and get any size and digit number.

There's also those mechanical counters they put in arcade machines to count the coins:

Just send them a voltage pulse and they tick up by one. Zero power needed to maintain the display between pulses.

[Twoflower]

By the way the still active 6 digit e-ink display (SCB721001 at Digikey, Pinout) should not be soldered down, but use a connector (https://www.te.com/usa-en/product-5-1734592-0.html). The same goes probably for most of the flex ribbons that show up. I don't think they're supposed do be soldered at all.

Still there's little how to actually drive it. But probably like described in chapter 6 here from a different display.

[RFZ]

Hey,
I accidentally came across a category of products that actually use very small low power 7 segment digits: OTP Security Cards
These are usually credit-card style or actual credit-cards that integrate a small ePaper display to show OTP or other access tokens.
Examples can be found here: https://www.smartdisplayer.com/products
These manufacturers also implement custom OTP algorithms and different form factors.

I also came across a video of someone who made his own ePaper display (not the one linked few posts before, but pretty similar). It's really just creating the electrodes on a PCB and bonding a ePaper display foil on top. So I guess making your own or ordering small quantities of custom displays from china is not that expensive.

Btw: Something that wasn't mentioned in the Video at all is the fact that ePaper Displays take a long time to update. Do you somehow want to make sure that the display always updates correctly? You may need a buffer cap to ensure the update finishes in case the product is powered up for a second or less...

[kelemvor]

I'd forgotten about this project until I stumbled across an element14 video wherein they used an epaper display.  They provided a link to the supplier (oddly, not element14 themselves) and it seems to be the mother lode of epaper display shops.  They've got a plethora of sizes of real epaper displays (not lcd or oled). 

Without further b/s the link is: https://www.waveshare.com/product/displays/e-paper/epaper-1.htm

Sizes in imperial, so you people will have to convert to métrique.

The site even appears to be geared directly toward enthusiasts, too.

[thm_w]

waveshare has good boards, Dave would not use any of these though as the price is too high.

Cheapest is $7, which is not bad though:
https://www.waveshare.com/product/displays/e-paper.htm?dir=asc&order=price

[EEVblog]

I accidentally came across a category of products that actually use very small low power 7 segment digits: OTP Security Cards
These are usually credit-card style or actual credit-cards that integrate a small ePaper display to show OTP or other access tokens.

This is kinda the application I had in mind.

[EEVblog]

waveshare has good boards, Dave would not use any of these though as the price is too high.
Cheapest is $7, which is not bad though:
https://www.waveshare.com/product/displays/e-paper.htm?dir=asc&order=price

They are too big.
I needed to display just 4 or 5 digits and that's it.

[EEVblog]

6 digit with battery indicator:
https://www.alibaba.com/product-detail/High-Quality-0-9-Flexible-FPC_62418139812.html

[EEVblog]

And:
https://www.aliexpress.com/item/32324536256.html