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Comment by staycoolboy | Hacker News Reader

I did NOT expect this to be under US$100. Definitely going for low power with SPI interface, but I don't get their refresh claim. SPI tops out around 1MB/s... 600x448x7 is ~235KB or 4 fps at 1MBps... but 15fps? That'd be 7MB/s, which is nigh impossible on SPI.

EDIT: 15 SECONDS PER FRAME, not 15fps. Thanks everyone for pointing that out. Still, amazingly cheap ... and almost no standby current after programming.

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> FULL REFRESH TIME 15s

That's 15 seconds per frame, or 0.067 fps.

That refresh rate is fine if you're using it to show the price of a rack of clothing, or various sensors - but you're not going to get smooth-scrolling text with it. The low-power interface is for those same battery-backed retail signage applications, where you're driving this, the microcontroller, and the wireless receiver with 3.7v from a coin cell.

Glad to see these becoming available for consumers and hackers! They've been hard to come by for years.

Or a "magic mirror" showing weather, calendar, time: you know, hours and minutes only :).

"Magic mirrors" don't work with e-ink since they require a lit display to shine through the mirror.

Good point. I suppose it just becomes a display then, rather than mirror — but with similar data.

More like the ubiquitous readouts in the "2001" Discovery ship.

I read the spec (column "FULL REFRESH TIME (S)") as saying 15 seconds per refresh not 15 refreshes per second. So 4 frames per minute which falls well within your calculation.

edit: Fixed to be 4 frames per minute not 4 frames per second.

Wouldn't that be 4fpm (frames per minute)? Which is no problem for signage, but not really practical as a secondary display...

Yes, my bad, it'd be 4 frames per minute.

It's seven color, not 7-bit. Also there might be just a "set color" command followed by 1-bit pixel data instead of a 4-bit pixel representation, or something.

I have a three color model from waveshare, and the way it works for it is you have to send a black and white bitmap, followed by a color and white bitmap. It's possible for these guys you need to repeat that five times.

I think its actually 15 seconds per frame, not frames per second

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