Simple NTP Clock Uses Custom RGB 7-Segment Displays

A great majority of hackers build a clock at some point. It’s a great way to get familiar with electronics and (often) microcontrollers, and you get to express some creativity along the way. Plus, you get something useful when you’re done! [Tadas Ustinavičius] recently trod this well-worn path and built a neat little NTP clock of their own.

The build uses an ESP 12F as the core of the operation. It’s charged with querying an NTP time server via its WiFi connection in order to maintain accurate timekeeping around the clock. For display, it drives a series of custom 7-segment displays that [Tadas] built using 3D-printed housings. They use WS2812B addressable LEDs and thus can display a rainbow of colors.

For initial configuration, the phone creates its own WiFi hotspot with a web interface for changing settings. Once configured, it connects to the Internet over WiFi to query an NTP server at regular intervals.

It’s a simple build that does a simple job well. Projects like these can be very valuable, as they teach you all kinds of useful skills. If you’ve been working on your own clock design, don’t hesitate to let us know. You can use a microcontroller, relays, or even a ball.

Dev Board Watch Takes Path Of Least Resistance

Building your own watch or clock is kind of a maker’s rite of passage. Once upon a time, if you went with a wrist watch, you’d typically work on producing your own compact PCB with everything crammed into a typical watch form factor, maybe relying on a simple binary output for compactness and simplicity. Times have changed, however, and [Arnov]’s design is altogether different in its construction.

The build relies on a XIAO ESP32-C3 microcontroller board as the brains of the operation. It’s paired with the XIAO expansion board. It’s designed as a carrier for the ESP32-C3, giving it a bunch of IO that’s accessible over readily-accessible connectors. It also features a display, a real-time clock, and a battery — pretty much the three main things you’d need to add to an ESP32 to turn it into a watch.

Thus, with the electronics pretty much done, it was simply up to [Arnov] to turn the device into a watch. He achieved this by screwing the frame and strap of an old Casio watch to a 3D printed carrier for the XIAO expansion board. With that done, it was simply a matter of writing the code to show the time from the RTC on the display. There’s no connectivity features, no smart stuff going on — just the time and date for your perusal.

Some might decry the project for simply slapping a watch band on a devboard. Or, you could look at how this indicates just how fast and easy development can be these days. Once upon a time, you could spend weeks trying to find a cheap display and then further weeks trying to get it working with your microcontroller. Now you can spend $20, get the parts in a few days, and get your project blasting along minutes later.

If you’ve done an altogether more ornate watch build of your own, we’d love to see that, too. Show us on the tipsline!

Educational Arduino Clock Uses Analog Meters For Display

When it comes to educational electronic projects, it’s hard to go past building a clock. You learn tons about everything from circuit concepts and assembly skills to insights about the very nature of time itself. And you get a clock at the end of it! [hamblin.joe] wanted to do a simple project for kids along these lines, so whipped up a neat design using analog meters to display the time.

The build relies on that old stalwart, the Arduino Uno, to run the show. It’s hooked up to a DS3231 real-time clock module so it can keep accurate time for long periods, as is befitting a clock. Displaying the time is done via the use of two analog meters, each fitted with a custom backing card. One displays hours, the other, minutes. The analog meters are simply driven by the PWM outputs of the Arduino.

It’s not a hugely complex project, but it teaches so much. It provides an opportunity to educate the builders about real-time clocks, microcontroller programming, and even the concepts behind pulse width modulation. To say nothing of the physical skills, like learning to solder or how to assemble the laser-cut enclosure. Ultimately, it looks like a really great way for [hamblin.joe] and his students to dive into the world of modern electronics.

How Many Time Zones Are There Anyway?

Nowadays, it’s an even bet that your newest project somehow connects to the Internet and, thus, to the world. Even if it doesn’t, if you share your plans, someone might reproduce your creation in some far distant locale. If your design uses time, you might need to think about time zones. Easy, right? That’s what [Zain Rizvi] thought until he tried to deploy something that converted between timezones. You can learn from his misconceptions thanks to a detailed post he provides.

You might think, “What’s the big deal?” After all, there’s UTC, and then there are 12 time zones ahead of UTC and 12 time zones later. But that’s not even close to true.

As [Zain] found out, there are 27 hours in a full-day cycle if you count UTC as one hour. Why? Because some islands in the Pacific wanted to be on the wrong side of the International Date Line. So there are a few extra zones to accommodate them.

You can’t even count on time zones being offset by an hour from the previous zone. Several zones have a half-hour offset from UTC (for example, India’s standard time is 5.5 hours from UTC). But surely the offset is always either a whole number or a number where the fractional part is 0.5, right?

Um, no. Nepal wants the sun to be directly over the mountain at noon, so it offsets by 45 minutes! [Zain] wonders — as we do — what would happen if the mountain shifted over time? Until 1940, Amsterdam used a 20-minute offset. Some cities are split with one half in one time zone and another in the other.

Of course, there are the usual problems with multiple names for each zone, both because many countries want their own zone and because the exact same zone is different in different languages. Having your own zone is not just for vanity, though. Daylight savings time rules will vary by zone and even, in some cases, only in certain parts of a zone. For example, in the United States, Arizona doesn’t change to daylight savings time. Oh, except for the Navajo Nation in Arizona, which does! Some areas observe daylight savings time that starts and ends multiple times during the year. Even if you observe daylight savings time, there are cases where the time shift isn’t an entire hour.

Besides multiple names, common names for zones often overlap. For example, in the United States, the Eastern Standard Time zone differs from Australia’s. Confused? You should be.

Maybe we should have more respect for multiple time zone clock projects. We’ve noticed these problems before when we felt sorry for the people who maintain the official time zone database.

A Clock Made Out Of Electromechanical Relays

Electromechanical circuits using relays are mostly a lost art these days, but sometimes you get people like [Aart] who can’t resist to turn a stack of clackity-clack relays into a functional design, like in this case a clock (article in Dutch, Google Translate).

It was made using components that [Aart] had come in possession of over the years, with each salvaged part requiring the usual removal of old solder, before being mounted on prototype boards. The resulting design uses the 1 Hz time signal from a Hörz DCF77 master clock which he set up to drive a clock network in his house, as he describes in a forum post at Circuits Online (also in Dutch).

The digital pulses from this time signal are used by the relay network to create the minutes and hours count, which are read out via a resistor ladder made using 0.1% resistors that drive two analog meters, one for the minutes and the other for the hours.

Sadly, [Aart] did not draw up a schematic yet, and there are a few issues he would like to resolve regarding the meter indicators that will be put in front of the analog dials. These currently have weird transitions between sections on the hour side, and the 59 – 00 transition on the minute dial happens in the middle of the scale. But as [Aart] says, this gives the meter its own character, which is an assessment that is hard to argue with.

Thanks to [Lucas] for the tip.

An Apple ][ With A Pendulum

Clocks are a favourite project here, and we can say we’ve seen all conceivable types over the years. Just a software clock on a retrocomputer perhaps isn’t the coolest among them, but [Willem van der Jagt ]’s Apple][ clock has a little bit extra. It takes its time reference from a real pendulum, on an antique wall clock.

A proximity sensor next to a metal pendulum gives an easy way to generate a digital pulse on each pass, but leaves the question of how to transfer it to the computer. With computers of this age the circuitry is surprisingly simple, and in this case he’s sending an interrupt to the machine which the software can pick up for its timing. There is a small logic circuit between the sensor and the interrupt allowing him to gate the pendulum line, triggered from one of the output lines exposed on the Apple’s game port.

The code is written in assembly, and counts the number of pendulum swings before incrementing the number of minutes. It’s an enjoyable reminder of the days when the architecture of a computer was this accessible, and for those of us whose past lies in the Sinclair world it’s also been a little peek into something of how the Apple works.

We think this is the first pendulum-driven retrocomputer clock we’ve seen here at Hackaday, as you might understand when a clock has a pendulum it’s usually a more traditional design.

Resistor Color Code Clock Is A Bit Of Fun

Younger electronic engineers may see resistors with old-style color codes to display their values a little less than those from previous years, but if there’s a shibboleth among those who wield a soldering iron it’s probably something similar to instinctively saying “1K” when asked “Brown-black-red?”. Colors as numbers can be used outside resistors, for example in a clock, as [Det Builds Stuff] shows us with an ESP32 TFT dev board.

It’s fair to say that this is more of a software project than a hardware one, but that’s not necessarily a bad thing as he takes us though the process of creating a Network Time Protocol (NTP) capable clock with the dev board. He claims it may be the world’s first resistor clock, something we’d have to disagree with, but beside that we can see this could make a neat little desk ornament with a 3D printed case.

Oddly though, we’d expect older engineers to face the same steep learning curve as younger ones when reading it, because it’s easier to recognize visual sequences of numbers as preferred resistor values than it is to visually decode each one every time.

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