DIY Night Clock Projector (2018) | Hacker News Reader

DIY Night Clock Projector (2018)

microengineer.eu

166 pointsGeoAtreides48 comments

I got a projector clock for Christmas when I was a boy in the 90s. I was so excited to go to bed. I set the clock up, got the projection going, took my glasses off, got into bed and... realised I couldn't see it.

I bought a MicroVision Laser Projector from eBay a while ago. It doesn't need the usual focus adjustment and can project from 15cm to 2.5m. Originally only meant to be used with an iPod, I managed to get the VGA cable as well which will be useful.

Docs: https://www.projectorcentral.com/Microvision-SHOWWX_Laser_Pi... Tech details: https://www.techinsights.com/blog/look-inside-microvisions-p...

Can it run continuously for years?

Where’d you find the VGA cable? I’ve held on to my MV for years in hopes I could find time to resurrect it. I only had a dock connector, like you. I thought about just using composite and an external video DAC, but I know the thing can take a VGA signal as well.

It was just on eBay around the same time, didn't know it was hard to find, just needed it as the dock option was already obsolete by that point. Although I think I've now got a compatible iPod Nano found purely by chance.

Does someone know why all these small laser mems projectors are discontinued? Anyview, Sony, ... Is it a reliability issue?

I found them quite interesting for similar applications especially as there is no need to focus and an image on a curved abject is possible.

I have two of the microvision ones and I can tell you the reason: they have to scan to draw and that makes everything look very wobbly. It isn’t something you can clearly see but it is stil somehow visible (through peripheral vision I suppose). It makes looking at still images and text very tiring.

Theoretically you can make it scan faster and that’ll fix it, but there’s probably more to it than just faster scanning.

Thank you. I've never seen them live, only videos and picture stills. Is the wobbly image a problem if you are 5 meter away from the projected image?

As written i only know models not longer available: Nebra AnyBeam, Sony MP-CL1A, Celluon PicoPro, RIF6 Cube, My assumption was that they are all using the same MEMS unit and that this unit is not longer available for some reason.

PS: If one is interested in a tear down of such unit:

https://www.youtube.com/watch?v=RuNyQKvx9zc

One of mine is microvision, but the other one had a different brand (I don’t remember the brand though). But they are exactly the same machines except the text on them. The VGA accessory works perfectly with both.

Regarding the image quality, both getting the screen closer (I.e. having a smaller screen) or going farther from it helped. What also helped was the location of text! It is better in top and bottom but worse in the center because of the unique way it works: the mirrors swing in a resonant fashion. So there are more horizontal scan lines towards the minima and maxima of the vertical scan sine. It is a really brilliant technology overall!

Watching movies in the woods from distance, it was quite decent. The contrast is pretty good since black is actually black, very unlike lcd-based projectors. It didn’t have enough white for some scenes but we were watching dark horror stuff anyway :)

I hope they could eventually make it scan faster or get better timing to overcome the downsides.

I suspect there was a limit to how fast you can raster scan these and hence how many lines of resolution you can achieve. The next technological step with laser scanning was to move from straight lines to harmonic motion: your mirror has a resonant frequency and you vibrate one axis at a low frequency and the other at a much higher harmonic but now you need to draw your picture across a complex lissajous pattern with non uniform brightness, requiring a lot more dsp and timing precision I suppose. I was excited to see this progress but nothing commercial ever came of it. R&D was being done at Fraunhofer Institute.

The other problem with these laser projectors is the bright “sparkle” pattern they produce.

Image is impressively sharp

I think the sharp image is from the projector mounted to a professional camera lens, not the cheap AliExpress one...

Only the last pic seems to be from the pro lens. The others before are almost as sharp with just the small lens.

you can't really trust a photo of a projection

I've often wondered why mono LCD projectors aren't more common - it seems like they'd be easier to make by a nontrivial amount and allow higher brightness/efficiency. I guess it's a matter of market scale as usual, or maybe I just don't know the right search keywords. (You do see mono LCDs nowadays in SLA 3d printers though.)

I love this. I would really like to have a clock like this with the outside temperature and maybe a counter for unread messages.

A counter for unread messages on the bedroom clock? I can't think of anything more anxiety inducing for my sleep than that. Bedtime is the one time and place I want to fully disconnect from anything 'on-line'.

I even charge my phone in the other room just to eliminate the thought of reaching over from the bead to the nightstand to do 'smartphone things' with it.

It could be set with an allowed list of friends and family only. The idea for me would be to know if it's worth looking at my phone if someone I care about tried to reach me, or if I can keep my eyes closed a bit longer instead. I absolutely do not want an email or Slack messages counter, of course. But in any case, maybe you are right, and it's a bad idea entirely...

No, I agree: I'd want some kind of app/webui where I could select which people I really care about, and the counter will show me if those people, and only those people, have sent me messages. So basically, my most immediate family and my girlfriend and that's it. If any of them send me a message, I'm willing to check it out.

They make them. I used to have one years ago, minus the message notifications.

I've always wanted one of these. Unfortunately, I sleep on my side or stomach, so I'd never be able to see it.

You could mount it on the ceiling at the foot of your bed, then rotate it to shine at your bed's headboard!

But then I have the same issue, as I never look at my headboard! I made a bedside table alarm clock instead, it's pretty good.

I did too until I realised that I can just talk to my phone and ask it the time.

The added bonus is this method doesnt put out any light so it doesnt effect your sleep.

It does wake your partner, though.

Cool project. Does anyone know if they make those LCD screens in a higher definition? I've tried googling but I tend to find consumer electronics instead of electronic components.

Can you adjust the size to like 3' numbers?

I'm so near sighted the store bought ones that project on the ceiling are like trying to read the bottom row of an eye chart.

The article gives a formula for image width; the author also tried it with a Walimex Pro 10mm 2.8 lens, which gave a 2 meter width image.

I love the project in terms of creating something but actually using such a clock just gives me anxiety just thinking about it. Endless cycle of waking up, checking the time, calculating the rest hours until I need to get back and falling back to sleep.

One of several things I’ve done over the years to optimize my sleep is never look at the time if i wake up. just go back to sleep.

Maybe it can be connected to a voice-interface system so you have to actually tell it "show me the time".

Maybe attach an old iPad to you ceiling?

One would need many iPads for a 90cm wide image (about a yard for the non-SI), but hey, it seems like it'd be easy enough to gather obsolete iPads to pull that off...

It would be too bright for me. And it would probably be quite anxiety-inducing.

FWIW you could probably just recompile with a lower brightness

Edit: nvm, just reread and saw the rotary encoder. So no need to recompile!

I made one of these ESP8266-based clocks[1], which has a little web UI to configure it, including the brightness of the LEDs. I commented out some of the code (Octoprint, Bitcoin etc.) since I wanted it to be a simple as possible. Even at the lowest brightness the LED matrix can do I found it too bright for my bedroom, but covering it with a thick sheet of paper worked well, in daylight you can't see it's on at all (which is fine, I am not looking at it), at night it's just readable enough.

1: https://www.instructables.com/LED-Marquee-Scroller-Wemos-D1-...

This seems incredibly counter to good sleep hygine. There's extensive evidence that even relatively low levels of light harm sleep quality; blue light from white LEDs is particularly disruptive to circadian rhythm, and if you're having trouble falling to sleep, this seems like an excellent way to just ramp up your anxiety?

One of the best things I did for sleep anxiety was to NOT have a bedroom clock at all, my phone goes face-down, I disabled my watch's auto-backlight functions, and I've tried very, very hard to not try and figure out the time once I'm "going to bed." Thankfully my e-reader also doesn't have a clock displayed unless you tap something, so if I wake up, I can read (with an orange book reading light) until I'm sleepy.

The only lights I have that are on once I'm in bed are red LED night-lights (finding them was surprisingly tough.)

Literally never has determining what time it is helped me get back to sleep.

What about when you wake up and it's still dark and you don't know whether it's worth trying to go back to sleep?

Exactly so. "Do I have time to get another hour or two of sleep, or is it time to get up and make coffee?"

You and parent comment don’t have kids xD

That’s what alarms are for. You go back to sleep and your alarm will wake you up.

In my opinion it’s always worth trying to go back sleep if you’ve got an alarm.

Speaking for myself, there’s nothing worse for falling back asleep than looking at the time. When I wake at night and it’s dark, it might be 11pm, 2am, or 5am. I don’t want to know what time it is. I go back to sleep and unless it happens to actually be within minutes of my alarm, I’ll fall back asleep and never know what time it was.

I was thinking of building a touch-operated clock for that. Some sort of dongle with a single button that would vibrate the hour and quarter-hours like a church bell.

You could keep it under your blanket so you wouldn't need to move all that much to check the time.

Red filter could probably help

Can be easily solved by adding some kind of motion sensor. Wave hand and the clock projects the time on the ceiling. Have a 10-15 second time out period to turn off the projection.

I recall reading about a bedside clock which offers a dim and subtle colour-shift at certain times; for example, it might glow red until 4am, amber from 4-6am, and green from 6am onwards.

The idea was to offer you you the ability to roughly determine the time to aid decision-making (as another commenter wrote, 'is it worth trying to go back to sleep?') without the alertness and/or anxiety that interacting with a gadget that tells the exact time.

> There's extensive evidence that even relatively low levels of light harm sleep quality; blue light from white LEDs is particularly disruptive to circadian rhythm

Maybe not.

https://www.unibas.ch/en/News-Events/News/Uni-Research/Light...

Yeah, when I complained about sleep issues, projector clocks were one of the first thing my doctor mentioned. Right up there with screen time and food before bed. I was told no light, no clocks, phone on the other side of the room.

Anecdotally, removing my brains ability to worry about how soon I need to wake up has been one of the most impactful sleep hacks I've found.

What about including a red light filter?

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