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I wanted a clock that never needed setting. Things escalated

arstechnica.com

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Re: I wanted a clock that never needed setting. Things escalated

#161

Post by NateEag »

threeio wrote: post #154
o_enix_o wrote: post #82

Earlier quoted context omitted.

Fascinating, can you share why you need a 10Mhz reference?

(for me) Sometimes your job might make you run reference time for a large service provider... and then you need multiple reference signals... and then you realize you have spares that are going to be thrown away... and suddenly your home lab becomes way too geeky for you to admit to 99.999999989% of your friends... unless they also are on the same time email list as you ;)

> time email list

How do wannabe time nerds find this email list?

Re: I wanted a clock that never needed setting. Things escalated

#163

Post by mikewarot »

NateEag wrote: post #161
threeio wrote: post #154

Earlier quoted context omitted.

(for me) Sometimes your job might make you run reference time for a large service provider... and then you need multiple reference signals... and then you realize you have spares that are going to be thrown away... and suddenly your home lab becomes way too geeky for you to admit to 99.999999989% of your friends... unless they also are on the same time email list as you ;)

> time email list How do wannabe time nerds find this email list?

http://www.leapsecond.com/time-nuts.htm

Any time we fix an old radio that goes down to 60 Khz, I always have to see if WWVB is coming in loud enough to be heard.

Re: I wanted a clock that never needed setting. Things escalated

#164

Post by krabizzwainch »

skippyfish wrote: post #5

I can't decide how I feel about this article. On one hand, it's great. It's great that the author wanted to get something done, and thanks to the marvels of modern tech, they could do it with very little effort. But on the other hand... gosh , this was about the simplest software engineering challenge imaginable (toggle some I/O pins) and the simplest design task imaginable (make a featureless rectangular box). And t…

I have been stuck mentally on this article since it came out. Like, learning enough python to send the time to the display would still have made this a weekend project (I even went and found an adafruit 7 segment pi hat site and read their sample code). The effort is the interesting part to me, I want to read janky code that paints some kind a picture of someone learning. I don't care about finished, "polished" projects. I don't care that AI can know every single possible error that'll pop up and prevent it from happening, I want the clock to break and for the maker to say ohhhh yeah oops thats dumb.

I have had an eInk pi weather display in my living room for like 4 years now, pulling data from openweatherapi every half hour. It's my second favorite project (I made an eReader once... if you like waiting 5 seconds for a page to turn, do I have a product for you!) and I use it every single day. Sometimes it doesn't update when I didn't account for a possibility I didn't know about, and thats okay.

I get that this is someone writing for money and I have no experience in that realm, and I'm sure conde nast prefers faster writing for something less in depth... but I almost feel I should spend my monthly $3 elsewhere.

Re: I wanted a clock that never needed setting. Things escalated

#165

Post by MathMonkeyMan »

RetroTechie wrote: post #157
MathMonkeyMan wrote: post #67

This is a harder problem than it seems. I've been thinking and reading about it for a side project, but haven't done much testing yet. There are a few places to get the current time: - on-board real-time clock (RTC) connected to a continuous power source (e.g. button battery) - GPS - Colorado WWVB signal (60 KHz), Frankfurt DCF-77 (77.5 KHz), Cumbria NPL (60 KHz) - the internet (NTP, HTTPS servers, etc.) - mobile int…

> The best option is the RTC. Buy a DS3231, hook it up to your microcontroller and a button battery, and forget about it for a few years. RTC ICs are for use in bigger systems where main CPUs have other things to do. If you design a clock around a microcontroller dedicated to the task, that microcontroller can do the timekeeping all by itself. No extra IC needed. Also quartz oscillators (ones built from discrete part…

I forgot about the AC mains :)

My experience with embedded stuff is very limited -- just some hobby projects on the Pico.

From what I've read, though, the on-board oscillators (there are a few of them) can drift quite a bit. One data point [says][1] several seconds per day.

On the other hand, if what you want is a microcontroller with an accurate clock, they probably make those (just not the Pico).

[1]: https://forums.raspberrypi.com/viewtopic.php?t=29255

Re: I wanted a clock that never needed setting. Things escalated

#166

Post by NateEag »

mikewarot wrote: post #163
NateEag wrote: post #161

Earlier quoted context omitted.

> time email list How do wannabe time nerds find this email list?

http://www.leapsecond.com/time-nuts.htm Any time we fix an old radio that goes down to 60 Khz, I always have to see if WWVB is coming in loud enough to be heard.

Thank you!

Re: I wanted a clock that never needed setting. Things escalated

#168

Post by mark-r »

rcxdude wrote: post #95
seba_dos1 wrote: post #91

Earlier quoted context omitted.

> I've also kind of wondered if GPS might be able to give you a time less accurately but quicker. Sometimes I look at the NMEA GPS output, and it sometimes doesn't have a position fix, but it does give out a time + week number No. Accurate time is one of the prerequisites for acquiring a position fix, and it's the one that's the easiest and fastest to obtain from the sky. Typically a receiver should be able to get ti…

>Typically a receiver should be able to get time within seconds from cold start if there's enough sky visibility, and once it does it is as accurate as it gets regardless of position fix status. It'll be good to far better than seconds when it first gets a signal and will get more accurate (microseconds to nanoseconds) once it has a position fix because it can then compensate for the delays in the signal propagation…

I once researched how accurate GPS time is, and the answer is it's within 40 ns. Good luck finding a way to transmit that to your CPU that doesn't add a much larger delay.

Re: I wanted a clock that never needed setting. Things escalated

#169

Post by mark-r »

hn_submit wrote: post #156

I find it wasteful to make a simple clock running a full-scale Linux distro just to fetch and display the time. And it's running Python too, which is an interpreted language which is a 100 times slower than C or assembly. I didn't look at the code but if it's not interrupt driven it will be wasting even more power.

The beauty of living in the modern age is that there are times when you don't have to worry about being wasteful. This project is a perfect example.

It's likely that the most power consuming part of the clock is the display.

Re: I wanted a clock that never needed setting. Things escalated

#170

Post by mark-r »

thenthenthen wrote: post #66
mjevans wrote: post #10

I feel this article's premise too much. That's exactly the sort of clock I wanted to get my mom as a gift. Why is it so dang impossible to find a not trash simple LED clock that's 'large print', 'the right color', and not annoyingly too bright? A deluxe model might include a day of the week bar or dot and a month / day in month number (smaller than the time, mostly people care about the time)

My parents rely on mechanical clocks, adjusting and ‘winding’ weights almost every day, they take great joy and pride from the fiddling. It’s fun to hear the clocks announce the hour and slowly hear them drift over time.

My uncle was a huge clock collector. Many of his would go off on the hour, it was quite the spectacle.
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