Wow, this is intense!
Think twice before sampling it if you have any sensitivity to flashing lights. Might seem obvious, but apparently needs saying!
Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
11–20 of 85 posts
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#12Oh my, Rust vs JS. It's almost guaranteed there will be more comments about that than the actual treatment. That's awesome that you created something free. You might want to add a standard license to your disclaimer for better liability protection (something that already stands up in case law). Do you have any verification or adjustment mechanism to ensure the correct frequency across hardware variations? I assume th…
Interesting idea. An iPhone camera now can record 60 frames per second (and much more in slow motion mode), so it seems like it wouldn’t be that hard to make something that can verify the frequency with a pretty high degree of accuracy.
If you can only capture 60FPS, you cannot accurate measure a signal of 40Hz, since it is below the Nyquist frequency. (I know you mentioned the slow-mo camera which probably does have the bandwidth).
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#13Just a warning - running this for a few seconds has left my secondary display with an ongoing flicker which seems to be improving after 10 minutes and a reboot.
[edit to add] 10 minutes later - the flicker has gone (or I can't perceive it)
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#14Earlier quoted context omitted.
Yes that’s the thing I most worry about, surely it causes some aliasing and a “beat pattern” (how could it not?). The question is whether that matters much in practice. It seems to work quite well on an iPhone in a dark room with the brightness turned up— just close your eyes and put the phone near your eyes. And don’t forget to turn off silent mode to hear the audio! That one case covers so many users.
So that's why it wasn't working. Videos and everything else will except incoming calls works in silent mode just by turning the volume up. Why is this an exception?
Not sure actually, I’m always a bit uncertain about what the behavior should be with respect to audio playback and silent mode on iPhones.
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#15i have to say this intrigues me. Anyone who has dealt with alzheimers or dementia in relatives would be.
I wonder how hard it would be to output to a 4k video stream and atmos or something and then play on hi end home theaters?
tim
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#16Wow, this is intense! Think twice before sampling it if you have any sensitivity to flashing lights. Might seem obvious, but apparently needs saying!
I think your point just re-enforces the concept that light has a powerful effect on peoples brains.
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#17Earlier quoted context omitted.
Interesting idea. An iPhone camera now can record 60 frames per second (and much more in slow motion mode), so it seems like it wouldn’t be that hard to make something that can verify the frequency with a pretty high degree of accuracy.
If you can only capture 60FPS, you cannot accurate measure a signal of 40Hz, since it is below the Nyquist frequency. (I know you mentioned the slow-mo camera which probably does have the bandwidth).
Of course, you’re right about the Nyquist frequency (how could I forget the Nyquist-Shannon Sampling Theorem!). But I looked it up and the iPhone 15 slow motion mode can do up to 240 fps which is enough to easily measure it super accurately with a short sample.
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#18raw.githack.com [1] can be used to view the html without cloning it.
[1]: https://rawcdn.githack.com/Dicklesworthstone/anti_alzheimers...
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#19raw.githack.com [1] can be used to view the html without cloning it. [1]: https://rawcdn.githack.com/Dicklesworthstone/anti_alzheimers...
Ah, that’s a good hack. But won’t work if you want to use a custom domain except with a redirect.
Re: Show HN: Alzheimer's Buddy: Use Flashing Light and Sound at 40Hz
#20Earlier quoted context omitted.
Interesting idea. An iPhone camera now can record 60 frames per second (and much more in slow motion mode), so it seems like it wouldn’t be that hard to make something that can verify the frequency with a pretty high degree of accuracy.
If you can only capture 60FPS, you cannot accurate measure a signal of 40Hz, since it is below the Nyquist frequency. (I know you mentioned the slow-mo camera which probably does have the bandwidth).
You technically can measure over the nyquist frequency, for example here if you measure 80Hz with your 60Hz camera, you can be sure that either you really did the math wrong with the intended 40Hz, or it is actually the nyquist shadow frequency of your 40Hz oscillation!