A Whole Lot Of Stepper Motors Make The Most Graceful 7-Segment Displays

August 11, 2021 by Mike Szczys 23 Comments

Over the years we’ve seen many takes on the 7-segment display. Among the most interesting are the mechanical versions of what is most often an LED-based item. This week’s offering is from [John Burd], who published a very odd video showing off the clock he made. But look beyond YouTuber antics and you’ll see the stepper motors he used to turn the segments are dripping with graceful beauty. (Video, embedded below.)

Okay if you want to hear [Charlie Sheen] say “Raspberry P-eye”, this is the video for you. [John] used Cameo to get the (former?) star to talk about what was used to build the clock. Like we said, the video is weird. Let’s embrace that right away and then never talk about it again.

The thing is, the build is such a good idea. [John] went with some stepper motors you can source relatively cheaply from Ali Express and the like. Typically they’re around a buck or two each and have a couple of wings for screw mounting brackets. This builds on the segment displays we’ve seen that use hobby servos by allowing you finer control of how the segments move. Sure, the 90° rotation isn’t all that much to work with, but it will be much smoother and you can get fancy with the kinematics you choose. The only place we see room for improvement is the alignment of the segments when they are turned “off” as you can see the center segment in the video thumbnail below is not quite level. Maybe a linkage mechanism would allow for a hing mechanism that aligns more accurately while hiding the servos themselves behind the mounting plate? It’s in your hands now!

In the demo video you’ll also find some interesting test rigs built to proof out the project. One just endurance tests the mechanism, but the other two envision water-actuated segments. One pumps a hollow, transparent segment with colored liquid. The other tried to use water droplets sprayed in the air to illuminate laser segments. Both are cool and we’d like to see more of the oddball approaches which remind us of the ferrofluid clock.

Continue reading “A Whole Lot Of Stepper Motors Make The Most Graceful 7-Segment Displays” →

Relay Logic Nixie Tube Clock Checks All The Boxes

August 9, 2021 by Ryan Flowers 5 Comments

There are a few words in the electrical engineering lexicon that will perk any hardware hacker’s ears. The first of course is “Nixie tubes” with their warm cold war era ambiance and nostalgia inducing aura. A close second is “relay logic”. Between their place in computing and telecom history and the way a symphony of click and clatter can make a geek’s heart go pitter patter, most of us just love a good relay hack. And then there’s the classic hacker project: A unique timepiece to adorn our lair and remind us when we’ve been working on our project just a little too long, if such a thing even exists.

With those things in mind, you can forgive us if we swooned ever so slightly when [Jon Stanley]’s Relay Logic Nixie Tube Clock came to us via the Tip Line. Adorned with its plethora of clicking relays and set aglow by four Nixie tubes, the Relay Logic Nixie Tube Clock checks all our boxes.

[Jon] started the build with relay modules that mimic CD4000 series CMOS logic chips. When the prototype stage was complete, the circuit was recreated on a new board that mounts all 55 Omron relays on the same PCB. The result? A glorious Nixie tube clock that will strike envy into even the purest hacker’s heart. Make sure to watch the video after the break!

[Jon] has graciously documented the entire build and even makes various relay logic boards available for purchase if you’d like to embark on your own relay logic exploits . His site overflows with unique clock projects as well, so you can be sure we’ll be checking those out.

If you feel inspired to build your own relay logic project, make sure you source genuine Omron relays, especially if your Relay Computer Masterpiece takes six years to build.

Thanks to [Daniel] for sending this our way. Got a cool project you’d like to share? Be sure to send it in via the Tip Line.

Continue reading “Relay Logic Nixie Tube Clock Checks All The Boxes” →

Accurate Digital Clock Keeps Ticking With FPGA

August 8, 2021 by Chris Lott 12 Comments

Even the most punctual among us are content to synchronize their clocks to external time sources like navigation satellite constellations, network time servers, frequency-controlled AC mains, or signals broadcast by radio stations such as WWV, CHU, and DFC77 — but not [zaphod]. After building a couple of more traditional clocks over the years, he set his sights on making a completely isolated digital clock that doesn’t rely on external synchronization (well, except to initialize the time at first power-up).

The accuracy goal he set for himself was that of a Casio F-91W wristwatch, which is specified to maintain +/- 30 seconds per month (about 12 ppm). At the heart of the design is an oven-controlled crystal oscillator whose stability is in the single-digits parts-per-billion.

The counter chain that accumulates the time is implemented in an FPGA — admittedly overkill, but [zaphod] wanted to learn FPGA programming for this project as well. An ATmega328 drives the display and does other bookkeeping tasks. The whole design is partitioned into three PCBs which fit inside a custom 3D-printed case.

[zaphod] does a thorough job documenting his build, including the bugs and failures along the way. We like the honest summary he wrote at the project’s conclusion, noting things that could be improved or should have been done differently. Be sure to check out the GitHub repository, where all the source code and PCB design files are posted. How accurate is your wristwatch, if you even wear one anymore?

Wristwatch PCB Swaps Must Be In The Air

August 8, 2021 by Mike Szczys 19 Comments

Are we seeing more wristwatch PCB swapping projects because more people are working on them, or because we saw one and they’re on our mind? The world may never know, but when it comes to design constraints, there’s a pretty fun challenge here both in fitting your electronic wizardry inside the confines of an injection molded case, and in the power budget to make your creation run on a sippy straw of battery power.

Just this morning we came across [Joey Castillo’s] sensor-watch project. He chose the Casio F-91W as the donor wristwatch. It’s got that classic Casio look of a segment LCD display capable of displaying hours, minutes, and seconds, as well as day and date. But the added bonus is that we know these have decent water resistance while still providing three buttons for user input. Sure, it’s less buttons than the pink calculator watch we saw [Dave Darko] working on earlier in the week, but which would you trust in the pool?

Replacement PCB sized to use the same battery contact and CR2016 for power [via @josecastillo]

We see that [Joey] also chose to use the ATSAML22 microcontroller and sheds some light on why: it includes a built-in segment LCD controller! If you’re a peripheral geek like us, you can read about the SLCD controller on page 924 of the datasheet (PDF), it’s a whole datasheet onto itself.

The sensor part of the sensor-watch is a flex PCB breakout that allows you to swap in whatever sensor fits your needs. The first to be reflowed at [Joey’s] bench is a BME280 humidity sensor, which is most obviously useful for the included temperature measurements, but maybe it could also alarm at moisture ingress? [Joey] says you can swap in other parts as long as they’re in the QFN or LGA size range. We think an IMU is in order since there’s a lot of fun interaction there like the watch reacting to being positioned in front of your face, or to take tap-based inputs.

We think beginning with a donor watch is brilliant since pulling off a case, especially one that keeps water out, is 97% of the battle. But when your UI is unique to the watch world, sometimes you need to start from scratch like this wooden word clock wristwatch.

Cool Binary Clock Uses Old-School LEDs And A Fancy Graphic PCB

August 6, 2021 by Lewin Day 21 Comments

Ah, the 5mm LED. Once a popular choice, they’ve been supplanted in modernity by smaller SMD components and/or more capable RGB parts in recent years. However, they’re still able to do the job and are a great way to give your project that proper homebrew look. [Ian Dunn] chose those very parts to produce his 4017 Decade Binary Clock.

The clock uses only digital logic ICs to tell the time – there are no microcontrollers here! After four or five iterations over almost a whole year, [Ian] was finally able to coax the circuit into reliable operation. As you’d expect, it relies on a 32.768 kHz crystal to provide a stable clock. Fed into a 4060 binary ripple counter, that clock is divided down 14 times to deliver a 2Hz square wave. This then goes through a 4027 flip flop to get the desired 1Hz signal. From there, a bunch of extra logic handles counting the seconds, minutes, and hours, and resetting the counters as appropriate.

The PCB that houses the project is printed on directly by a flatbed inkjet printer, which [Ian] purchased when inspired by our previous article on how to get your PCBs made at the mall. He didn’t actually use it to make the PCB in this case, but the flatbed printer does a great job of putting graphics on the board.

The result is quite an attractive look that might surprise a few electronics enthusiasts who haven’t seen a graphic printed board before. It’s a technique we think could be used to great effect on conference badges, too. If you’ve experimented with similar techniques, be sure to drop us a line!

Parts Shortage Forces Creativity For This Recursive Clock Of Clocks

July 25, 2021 by Dan Maloney 9 Comments

We’ve been seeing a lot of metaclocks lately — a digital clock whose display is formed by the sweeping hands of an array of individual analog clocks. They can look fantastic, and we’ve certainly seen some great examples.

But in this time of supply pinches, it’s not always possible to gather the parts one needs for a full-scale build. Happily, that didn’t stop [Erich Styger] from executing this circular multi-metaclock with only thirteen of his custom dual-shaft stepper analog movements. Normally, his clocks use double that number of movements, which he arranges in a matrix so that the hands can be positioned to form virtual seven-segment displays. By arranging the movements in a circle, the light-pipe hands can mimic an analog clock face, or perform any of [Erich]’s signature “intermezzo” animations, each of which is graceful and engaging to watch. Check out a little of what this charmingly recursive clock has to offer in the video below.

[Erich] could easily have gotten stuck on the original design — he’s been at this metaclock game for a while, after all. The fact that the reduced part count forced him to get creative on the display is the best part of this build, at least to us.

Continue reading “Parts Shortage Forces Creativity For This Recursive Clock Of Clocks” →

Portable GPS Time Server Powered By The ESP8266

July 25, 2021 by Tom Nardi 31 Comments

Most Hackaday readers will be familiar with the idea of a network time server; a magical box nestled away in some distant data center that runs the Network Time Protocol (NTP) and allows us to conveniently synchronize the clocks in our computers and gadgets. Particularly eager clock watchers can actually rig up their own NTP server for their personal use, and if you’re a true time aficionado like [Cristiano Monteiro], you might be interested in the portable GPS-controlled time server he recently put together.

The heart of the build is a NEO-6M GPS module which features a dedicated pulse per second (PPS) pin. The ESP8266 combines the timestamp from the GPS messages and the PPS signal to synchronize itself with the atomic clock aboard the orbiting satellite. To prevent the system from drifting too far out of sync when it doesn’t have a lock on the GPS signal, [Cristiano] is using a DS3231 I2C real-time clock module that features a high accuracy temperature-compensated crystal oscillator (TCXO).