clock

592 Articles

Planetary Gears Tell Time In This Ornamental Clock

April 10, 2020 by 8 Comments

A clock is perhaps one of the the most popular projects among makers. Most designs we see are purely electronic and do not bother with the often more complicated mechanical part. Instructables user [Looman_projects] though was not afraid of calculating gear ratios and tooth counts for his planetary gear clock.

As shown in the picture, a planetary gear, also known as epicyclic gear, consists of three parts: a central sun gear, planetary gears moving around the sun gear and an outer ring with inward-facing teeth holding it all together. The mechanism dates back to ancient Greece but is still being used in car transmissions and has become quite popular in 3D printing. In his instructable [Looman_projects] has some useful inlinks including an explanation video of how planetary gear sets work and a website helping you to calculate the tooth counts for specific gear ratios. It is also noteworthy that he tried to cut the gears from aluminum with a waterjet which unfortunately failed because the parts were too small. What makes the clock visually stand out is the beautiful ornamental see-through design of the dial plate and hands made from laser-cut wood. Despite the mechanical gearbox, it is not surprising that the driving mechanism is based on ubiquitous pieces of digital electronics including an Arduino Nano, DS3231 RTC module, and a stepper motor. To avoid a cabling mess [Looman_projects] designed a custom PCB that interconnects all the electronics and says he even got some spare PCBs left for people interested in rebuilding the clock.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D printed version is lifting an anvil.

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Tell Time Like It’s 1960 With This All-Transistor Digital Clock

April 9, 2020 by 44 Comments

When you’ve got time on your hands, doing something the hard way can be therapeutic. Not that the present situation and the abundance of free time that many are experiencing has anything to do with [Leo Fernekes] all-transistor digital clock build, which he started a year ago with his students. But if you’ve got time to burn, this might be a good way to do it.

[Leo] says one of his design goals with this clock was to do it with the technology commercially available in 1960, which means relying completely on discrete components. And he and his students managed to do just that, with the exception of the seven-segment displays, which were built from the LED filaments from some modern light bulbs. Everything else, though, is as old school as it gets, and really underscores all the complexity that gets abstracted away from timekeeping with modern chips. The video below covers each module in detail, from the Schmitt trigger that cleans up the 50-Hz line frequency to the ring counters and diode matrices used to drive the display. We found the analog stair step dividers used to bring the line frequency down to a more usable pulse train particularly interesting. That clever bit of engineering saved 10 transistors over what would be required for traditional flip-flop dividers.

There’s a lot to learn from this design, and the execution is great too – we’re suckers for Manhattan-style builds, of course. Hats off to [Leo] and his lucky students on a great build.

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What Day Is It?

April 8, 2020 by 15 Comments

With much of the world staying at home at the moment, keeping track of our sanity and the day of the week is a bit of a challenge, especially without the normal daily routine to hold onto. To help with one of these problems, [phreakmonkey] has built a Day Clock. As the name suggests, it’s only purpose is to show what day of the week it is.

Avery simple device, the two main components are a servo and a Wemos D1 Mini, the popular ESP8266-based dev board. Using the NTPtimeESP library, it gets day of the week from the internet, and moves the servo to indicate the current day on a 3D printed face. Most readers should be able to whip one up in an hour or two, which can help keep sane in these interesting times.

For another Corona clock, check out [Elliot Williams]’ version that helps with keeping domestic peace. If you want to do something to combat the spread of the current epidemic, you can build a few face shields, make your idle computer available for Folding@Home or sew a few masks. Every bit helps.

Inverse Kinematics Robot Arm Magna-Doodles The Time For You

March 24, 2020 by 8 Comments

Following a surge of creativity fueled by the current lockdown, [Diglo] writes in with his tabletop clock driven by a robotic arm drawing on a Magna Doodle tablet. And if you have one of those still lying around with some old toys and don’t mind cannibalizing it for the project, you too can follow along the source files to build your own.

The clock works by exploiting the principle that Magna Doodle tablets work by being drawn on with a magnetic stylus. That way, to draw on one of them you don’t need to add a point of articulation to bring the pen up and down, [Diglo] simply attached a controllable electromagnet to the end of a two-dimensional SCARA arm. In total, the whole build uses three stepper motors, two to control the movement of the arm, and one on the back of the tablet to sweep a magnetic bar which “erases” it.

This clock is similar to another we’ve featured a few years ago, which also used a Magna Doodle, but greatly improves on the idea. If a Magna Doodle seems too childish to build a magnetic clock however, there’s always ferrofluidic displays to try to dip your fingers into, but we really think you should watch this one in action after the break first.

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LEGO My Colorful Custom Clock

March 23, 2020 by 7 Comments

[Sofia] spent a lot of time looking around for the perfect LEGO clock. Eventually, she realized that the perfect LEGO clock is, of course, the one you build yourself. So if you find yourself staring at the same old boring clock, contemplating time and the meaning of time itself, why not spend some time making a new timepiece?

You probably already had the LEGO out (no judgment here). This build doesn’t take a whole lot of building blocks — just a microcontroller, a real-time clock module, some LED matrices to display the digits, shift registers if they’re not already built into the matrices, and a pair of buttons for control. [Sofia] used an Arduino Nano, but any microcontroller with enough I/O ought to work. Everybody needs a colorful new way to block out their time.

We love the way this clock looks, especially the transparent panels in front of the LED panels. Given the countless custom pieces out there from all the special sets over the years, we bet you could come up with some really interesting builds.

If your kid is too young to tell time, try building a kid-friendly clock to give them segmented structure.

Via r/duino

144 7-Segment Displays Combine To Form A Mighty Clock

March 5, 2020 by 25 Comments

What do you do with 144 7-segment displays? If you’re [Frugha] you put them all together to create an epic clock. Each display has 8 individual LEDs — 7 segments, and a decimal point. Put that all together, and you’ve got 1152 individual LEDs to control. This presented a problem, as [Frugha] wanted to control the clock with a single Arduino Nano. Even charlieplexing won’t get you that many I/O lines.

The solution was a nifty little chip called the MAX7219. The ‘7219 speaks SPI and can control 64 individual LEDs. [Frugha] used 18 of them in the clock, giving him full control over all his LEDs. That’s pretty impressive, considering the last matrix 7-segment display we saw required 48 Arduinos!

Another problem is memory – 1152 “pixels” would quickly overrun the 2KB RAM in the ATmega328. This is a clock though — which means only digits 0-9 and a colon. [Frugha] picked a nice font and hand-coded lookup tables for each digit. The lookup tables are stored in ROM, saving precious RAM on the Arduino.

A clock wouldn’t be any good if it wasn’t accurate. A Tiny RTC supplies battery-backed time data. [Frugha] wrapped everything up with a neat layout on a custom PCB. Sure, you could put it in a case, but we think a clock this crazy deserves to be left open – so you can see it in all its glory.

Gorgeous Clock, And Not A Line Of Code In Sight

March 4, 2020 by 41 Comments

[Harry] dropped us a note to let us know about his completed CMOS clock project, and we’re delighted that he did because it’s gorgeous. It’s a digital clock satisfyingly assembled entirely from hardware logic, without a single line of code. There are three main parts to this kind of digital clock: ensuring a stable time base, allowing for setting the time, and turning the counter outputs into a numerical display.

Keeping accurate time is done with a 32.768 kHz crystal, and using CMOS logic to divide that down to a 1 Hz square wave. From there, keeping track of hours and minutes and seconds is mostly a matter of having counters reset and carry at the appropriate times. Setting the clock is done by diverting the 1 Hz signal so that it directly increments either the hours or minutes counter. The counter values are always shown “live” on six 7-segment displays, which makes it all human-readable.

The whole thing is tastefully enclosed in a glass dome which looks great, but [Harry] helpfully warns prospective makers that such things have an unfortunate side effect of being a fingerprint magnet. Schematics and design files are provided for those who want a closer look.

This clock uses a crystal and divider, but there’s another method for keeping accurate time and that’s to base it off the alternating current frequency of power from the grid. Not a bad method, albeit one that depends on being plugged into the wall.