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riskableyesterday at 5:13 PM7 repliesview on HN

I want to see someone convert one of those cheap projection clocks like this: https://www.homedepot.com/p/La-Crosse-Technology-5-in-Color-...

The red projection is just the right brightness (at night) but it sucks that it's not wifi-enabled so you can't just get it to NTP sync (or hook up a GPS receiver). The projector part of the clock is a separate device that's attached to it via a ribbon cable. I would reverse engineer it myself but I haven't got the time.

Ideally, I'd want a matrix of LEDs projected on to the ceiling so I could get more info than just the time. Such clocks exist but they're super duper expensive! Example: https://buyfrixos.com/


Replies

stavrosyesterday at 5:26 PM

If you're looking for something low brightness, I made one: https://www.stavros.io/posts/i-made-another-little-bedside-c...

ElevenLatheyesterday at 5:36 PM

The one you linked claims to have "Atomic Time" which usually means syncing by radio from WWV/WWVB. I have several cheap wallclocks like this (though none with a projector) and they are always accurate with no noticeable drift AFAICT. Have you tried that particular one and found its accuracy wanting? I think, in principle at least, there should be less jitter in this method than using NTP over a computer network.

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dannyfritz07yesterday at 11:01 PM

I love my WWV/WWVB clocks. It is nice never having to set them and they are all within a second of my NTP clocks.

Now if only I could turn off the clocks on my oven and microwave...

lostloginyesterday at 5:21 PM

Undermining the spirit of HN: By the time you’ve spent a few hours hacking away and bought any parts, that price is probably not too bad.

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mmsimangayesterday at 5:24 PM

+1 I have a couple of digital.clocks from Temu. They look nice but cannot keep the correct time. They slowly edge ahead and in a month they are about a minute ahead. It is annoying having to correct the clock and would be great if they time from WiFi connected source.

btheconqueroryesterday at 8:07 PM

Some clocks also update over radio. Oregon Scientific used to make the best bedside atomic clock ever. Super simple, with the projector, was an atomic clock that updated automatically via radio and had a pleasant, crescendo alarm that would start off nice and get more aggressive. They don't make it anymore :/

alnwlsnyesterday at 6:43 PM

Depending on how dark your room is you might get by with an ordinary but bright LCD screen and a camera lens. There's a pretty common 240x240px, 1-inch square TFT display on amazon or other usual places you might start with.