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/
Cool project!
The most interesting part, IMO, is the "SRAM with EEPROM backup" chip. It allows you to persistently save the clock hands' positions every time they're moved, without burning through the limited write endurance of a plain old EEPROM. And it costs less than $1 in single quantities. That's a useful product to know about.
I'm not sure if this is the same technology, but regardless it's also cool: https://www.adafruit.com/product/1897
If you like this but don't want to get your hands as dirty, have a look at the Crazy Clock: https://www.tindie.com/products/nsayer/crazy-clock/
I got one for my daughter. The erratic ticking eventually became a distraction when she was studying, so we have retired it for now. But we got a lot of amusement out of it.
> Early clock - keeps time anywhere between 0 and 10 minutes fast. For those who like to set their watch ahead to avoid being late. This clock keeps you from trying to "compensate," because you never know how early it is at the moment.
That's pretty genius for many ADHD-type folks. Only problem is a modern household has many clocks in view, so you'd need to commit to just not setting them.
Cute, but the original clock used to run on AA battery that needs a replacement every two years or so, and now it needs a power supply. Or some big battery recharge/replacement every few hours maybe days.
How does this keep track with DST?
Looking at the code [1], it looks like if the actual time is 1 hour ahead of the displayed time, then we get 10 pulses per second to leap forward. Otherwise, the clock stops running for an hour to fall back.
https://github.com/jim11662418/ESP8266_WiFi_Analog_Clock/blo...
You have two choices: either assume everyone is asleep at 2 am and won't notice when it happens, or else advance 11 hours. My LaCrosse clock does the latter.
And that's pretty much fine for a project like this, seeing as most (all?) locations jump you between DST and not DST at night. So the clock will be off at most for an hour during the night.
I'm currently making something similar but using a BKA30D-R5 (a dual stepper motor used in car dashboards) and a hall sensor to zero the hands.
Yes, this project screams for some kind of sensor to detect when the hands reach some known position.
Yeah, it's super quick to start with a MK I eyeball to set them, but having a sensor just avoids any drift. I got away with using one by taking a reading and moving the other hand to check they weren't on top of each other already, and then doing a full rotation between readings.
See also the "Ventinari clock": https://github.com/iracigt/ventinari-clock https://www.akafugu.jp/posts/products/vetinariclock/
Some years ago I made a ESP-based clock that used 60 LEDs in a circle that project RGB shadows via a cone at the center. I used the same WeMos D1 Mini board.
I remember seeing this on Hackaday. Very clever idea!
Of note, having recently shopped at Walmart for a self-setting alarm clock (what I once knew to be “atomic”):
Apparently the entity today known as Sharp sells “AccuSet(tm)” branded clocks that “automatically set time”… but they’re just factory pre-set with a button cell and they include a slider on the bottom to set a timezone offset (only for US timezones). If you’re lucky, the clock’s battery is still good and the clock “set itself” out of the box several minutes late.
If you’re unlucky - surprise, you get to manually set the time anyways.
https://www.amazon.com/Sharp-Digital-Alarm-AccuSet-Automatic...
These clocks are irritating because they show up in the results when searching for “radio atomic clock” and similar, and it can be very hard to figure out if they actually use the WWVB radio signal. I’ve concluded that none of them do, because WWVB is only reliable in (most parts) of the US, and companies only want to make things that appeal to a global audience now. La Crosse seems to be the only one that makes them, and unfortunately most of their designs lack any style (i.e. they’re ugly).
[delayed]
It's like they hired a design firm in the early 00's and decided that design language is the peak of human horology... I wish they'd make a couple new designs.
You want a self-setting radio clock that receives the LF broadcast from WWVB.
There was a kerfuffle a few years back about the funding for the station being cut, but luckily that did not come to be.
If you want a pure software solution get yourself an old atomic clock and https://github.com/jj1bdx/WWV play some tunes to set the time.
Great idea!
makes me wonder what if I just wanted to sync with nfc every once in a while. wifi seems overkill for this. maybe it could be done much cheaper with nfc sync witha phone twice a year?
You often have a radio clock source like DCF77 that all those radio controlled clocks use
An ESP32-C3 Super Mini can be found for below 3$ (cheapest I had was 1.58€). Since the original clock is 3.88$, it can't be that much cheaper.
ESPs are so cheap that you couldn't possibly save very much money, and the way economies of scale work it may or may not be cheaper to use NFC anyways.
We've been shopping for a simple bathroom clock to replace our final Amazon Echo and leave that increasingly dystopian ecosystem. There are some models that use Bluetooth on your phone to sync the time. I could imagine BLE being a good low-power and relatively stateless solution. But given our goals, we're not going to install an app on a phone just to maintain a wall clock. (I'd be fine if Android provided BLE time sync as a built-in service.)
Home assistant has pretty good BLE capabilities. But honestly, as has already been pointed out wifi is already really cheap.
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.
If you're looking for something low brightness, I made one: https://www.stavros.io/posts/i-made-another-little-bedside-c...
+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.
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.
That's assuming you don't like hacking and would pay to not have to do it, which is generally not the case around here.