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A project log for 2018 Open Hardware Summit badge

electronic conference badge for 2018 Open Hardware Summit attendees

oshparkoshpark 05/14/2018 at 17:026 Comments

I recently came across this interesting low cost e-paper which features a backlight:

epaper display E paper display GDE0213B1 with matched front light used for dark place

www.buy-lcd.com/index.php?route=product/product&product_id=57529

It does seem that backlight might be useful as the Open Hardware Summit will be indoors.

I may order one of these displays to see how difficult it is to interface.  The advantage of Waveshare is that there is already a working library with the ESP trINKet design.

Discussions

Alex Camilo wrote 05/27/2018 at 01:41 point

I'm pretty confident that the 2.13" display from waveshare (PN. 13368 ) is the same part as the 2.13" from good-display (P.N. GDEW0213Z16)

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Alex Camilo wrote 05/27/2018 at 00:52 point

E paper should be pretty readable with indoor ambient light. It might make sense to go with the most cost effective display. It looks like the back-lit models are about 2$ more expensive then their non back-lit equivalents.

I've worked with other displays from this company and they (or whoever resells them) will provide you with source code (that i got working on the ESP32). It's a bit ugly and it uses bit-banged GPIO to emulate SPI but it worked.

My understanding is that all these displays share the same controller and ribbon cable pinout. This was true for the 3 that I got. I could use the demo for the smallest of my displays and it would still work when i swapped in the larger ones.

Additionally These displays are re-badged and sold under different names. Ben Krasnow has a video on hacking these to refresh faster. The company he got his kits from is in fact "Waveshare" but you can see him looking at the controller datasheet and it's from good-display. 

https://youtu.be/MsbiO8EAsGw?t=864

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ðeshipu wrote 05/14/2018 at 18:10 point

Doesn't that pretty much defeat the whole advantage of using e-paper? I mean, if you want backlight, then the liquid crystal displays are much cheaper and also very low power — it's the backlight that eats all the energy.

I think I went through the steps you are going through now with my #CircuitPython Badge, and ultimately decided to simply write the name on the badge with a sharpie, and provide a large, bright, low-resolution display just as a programmable attention-grabbing device. You can't possibly find a lower power display than a sharpie.

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davedarko wrote 05/15/2018 at 06:03 point

You can switch off the light when there's enough light to read the e-paper, but you can't do that with an LCD/TFT/OLED, so there is some advantage.

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ðeshipu wrote 05/15/2018 at 06:34 point

Actually you can switch the backlight with the monochrome LCDs, that was my first attempt at the badge design, remember? Lameboy also does that.

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Clayton G. Hobbs wrote 05/15/2018 at 12:19 point

Those are called transflective LCDs, a family of displays that's also Wikipedia's favorite kind of word.

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