Inverse Kinematics Robot Arm Magna-Doodles The Time For You

March 24, 2020 by Erin Pinheiro 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 Kristina Panos 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 Adam Fabio 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 Donald Papp 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.

Just When You Thought There Was Nothing New In Nixie Clocks…

March 3, 2020 by Jenny List 9 Comments

Nixie clocks have become such a staple in our community as to have become mundane. They’re pretty, but show us something new! It seems [Marcin Saj] has done just that with his offering, because with a bank of 18 IN-2 Nixie tubes he’s telling the time – but in binary rather than the usual decimal.

The tubes are arranged in three banks of six, the upper registering hours, the middle minutes, and seconds on the lowest. Each one only uses two digits, as you might expect from a binary device they are 0 and 1. Behind is a large PCB with the Nixie sockets, and on the back of that in sockets are a pair of Nixie driver boards, a real-time clock module, temperature sensor module, PSU module, and either a Particle Photon or an Arduino Nano IoT. This two-option set-up for the choice of dev board is unusual, and there is code for both of them in the GitHub repository.

The result is eye-catching and unusual, and certainly a departure from the usual Nixie digital clock. Hackaday readers are probably more likely than the average Joe or Jane to be able to read binary at a glance, watching it in action in the video below the break is an interesting exercise in testing one’s binary-aptitude.

Meanwhile if binary Nixies are too commonplace, how about binary neon lamps?

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Giant Clock Made In The Nick Of Time

March 2, 2020 by Kristina Panos 12 Comments

When [tnjyoung] was asked to build a huge lighted clock for a high school theater’s production of Cinderella with only two weeks before opening night, he probably wished for a fairy godmother of his own to show up and do it for him. But he and his team pulled it off, and it looks amazing. That medallion in the middle? It was laid out painstakingly by hand, using electrical tape.

This thing is 12 feet wide and weighs more than 500 pounds. Even so, it isn’t a permanent set piece, so it has to move up and down throughout the show on airplane cables. Now for the minutiae: there’s an Arduino Uno with built-in Wi-Fi that receives UDP commands from a phone to raise and lower the clock at the appropriate times. The ‘duino is also controlling two stepper motors, one for the hour hand and one for the minute hand.

Time is almost a minor character in the story of Cinderella, since she has to get back by midnight. Because of this, [tnjyoung] programmed a dozen or so time cues that move the steppers at various speeds to achieve different effects, like time flying by as she dances the night away with the Prince. Hour you still just sitting there? Sweep past the break to watch the build process fly by in a matter of minutes.

Got all the time in the world? Make a clock out of clocks. Clocks all the way down.

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Nixies Adorn A Cold War Relic To Make A Geiger Clock

February 27, 2020 by Dan Maloney 22 Comments

Say what you will about the centrally planned economies of the Soviet bloc during the Cold War, but their designs had a brutal style all their own. When one comes across an artifact from that time, like a defunct Polish Geiger counter from 1971, one celebrates that style the only way possible: by sticking Nixies tubes on it and making it into a Geiger clock.

Right off the hop, we’ve got to say that we’re in love with the look of [Tom Sparrow]’s build. And we’ll further stipulate that most of the charm comes from the attractive Bakelite case of the original Geiger counter. This looks like the real deal, with the marbleized look presumably caused by different color resins mixing in the mold. [Tom] did an admirable job bringing back the original shine with some polish and elbow grease; no doubt the decades had taken their toll on the original shine. The meter was gutted to make room for the clockworks, which is an off-the-shelf Nixie module. The tubes stick through holes drilled in the top; a pair of LEDs adorn the front panel and an incandescent bulb provides a warm glow behind the original meter. Combined with the original rotary switch and labels, the whole thing has a great look that’s perfect for a desk.

We’ve featured a lot of retro-classic Nixie builds, from digitizing a 1940s radio to a 1970s multimeter turned into a dice-roller. As for Nixie clocks, we’re just glad to take a break from the Nixie steampunk trend for a bit.

[via Dangerous Prototypes]