Xiaomi launches the InkPalm 5 mini e-reader for 599 yuan (~$91)

[Quoth]

The current is probably less than 0.1uA. You need 1M resistor to +12V and then AC coupling to op-amp, 100nF, so you have good gain for any PWM signal.

I've plenty of photodiodes/transistors, but unless you are visiting Limerick-Shannon, that's no use.

Some mice have a rotary encoder using IR LEDs and photo transistors, but maybe only old ones with a ball. Current ones might use a switched rotary encoder for the wheel that's also a middle button.

[Renate]

To get any speed you need to run this in constant voltage, current mode. Non-inverting input to a 2 V reference, output through a high value resistor to diode pulled directly to V+.

In this world of obsolescence you have to lay out some serious money before you get a knob with IR interrupters. Cheesy contacts are good enough. And if it breaks?

I was somewhere in your neighborhood once to see the big refractor telescope and do the usual tourist things.

[kandwo]

Originally Posted by rowe

You can use an Opple Light Master to measure the PWM. But as others said the only thing that really matters for an individual is whether the PWM on the device affects you or not. For this reason I've never bothered buying one as I quickly tell whether the PWM is affecting me or not.

The only readers I've ever known marketed as DC-dimming are Hisense. But even though their lighting is probably the lowest risk for uncomfortable PWM, even DC-dimming lighting sometimes uses PWM between steps.

Ereaders that don't have negative PWM affects for me:
Hisense, old Boox (Poke Pro, Nova 2/3), various Kindles

E-ink devices whose PWM lighting is unusably uncomfortable for me:
Dasung monitors, newer Boox (Palma, Page, Tab Ultra C, Mira)

This will vary across users as different people have different PWM sensitivities.

According to https://onyxboox.com/ they use DC lighting with "flicker free" technology. Could it be something else?

For me, I get nauseous from very cold light. So my Hisense A5 Pro was a no go in that regard. I don't have a problem with headaches when it comes to frontlights, but I just dislike them in general - they are not warm enough on modern devices. Except for the Palma frontlight being very uneven, I don't perceive it as much worse than the one on the A9, for instance.

[Renate]

Originally Posted by kandwo

For me, I get nauseous from very cold light.

For me, I get nauseous on a Merry-go-round (Carousel).

OTOH, I've never noticed flickering on anything.

[rowe]

'According to https://onyxboox.com/ they use DC lighting with "flicker free" technology. Could it be something else?'
Interesting. I'd assumed PWM as I've seen a few ereaders that say they have non-dc-dimming PWM lighting (e.g. Bigme). I did find the Palma lighting too bright on its lowest setting and too cold. Also, there's still often PWM between the steps of DC-dimming lighting but I think that's generally thought to be a non-issue. Maybe BSR plus the lighting was an issue for me.

[Extricated]

Originally Posted by kandwo

According to https://onyxboox.com/ they use DC lighting with "flicker free" technology. Could it be something else?

For me, I get nauseous from very cold light. So my Hisense A5 Pro was a no go in that regard. I don't have a problem with headaches when it comes to frontlights, but I just dislike them in general - they are not warm enough on modern devices. Except for the Palma frontlight being very uneven, I don't perceive it as much worse than the one on the A9, for instance.

They definitely don't use DC lighting - it's been confirmed with a high shutter speed that they use PWM, which doesn't surprise me. They're very well-known to flout the consumer laws of other countries with their excuse for a "warranty", so false advertising on their part wouldn't be a headline for me.

[kandwo]

Originally Posted by Extricated

They definitely don't use DC lighting - it's been confirmed with a high shutter speed that they use PWM, which doesn't surprise me. They're very well-known to flout the consumer laws of other countries with their excuse for a "warranty", so false advertising on their part wouldn't be a headline for me.

Do you have a source for that? It would be interesting to see the tests.

Regarding their warranty, I fully agree.