A Z80 Micro TV Clock

As an adventure in computer history, [Len] built up a clock. The Z80 Micro TV Clock brings together a homebrew computer and three Micro TVs into a rather large timepiece.

The computer powering the clock runs the CP/M operating system. This OS was eventually released as open source software, and a variety of homebrew computer projects have implemented it. This clock is based on an existing breadboard CP/M machine, which includes schematics and software.

With an OS running, [Len] got a text editor and C compiler working. Now custom software could be written for the device. Software was written to interact with a Maxim DS12885 Real Time Clock, which keeps the time, and to output the time to the display controllers.

The Micro TVs in this build are Sony Watchman displays featuring a 2″ CRT. The devices had no video input port, so [Len] ripped them open and started poking around. The NTSC signal was found by probing the board and looking for the right waveform.

To drive the TVs from CP/M, a custom video driver was built. This uses three relatively modern ATmega328P microcontrollers and the arduino-tvout library. All of these components are brought together on a stand made from wood and copper tubing, making it a functional as a desk top clock

Star Gate LED Clock Has Plenty of Pizazz

[David Hopkins] has finally finished off his Star Gate LED clock over on Hackaday.io and it looks fantastic.

We originally featured his progress with the project in Hacklet 18 – Tick Tock, it’s Time for Clocks, and we’re happy to say it’s finally complete. The clock features 60 WS2812 LEDs to simulate the Star Gate’s chevrons — and to tell the time. Under the hood is an RTC, an Arduino Nano, an LDR and even an hourly ‘chime’. Did we mention it also automatically dims at night?

What we’re almost more impressed with is the build quality, which [David] doesn’t actually mention how he did it – regardless, it looks great! Stick around after the break to see a video of it in action, so you can really appreciate the clock’s capabilities.

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The ChronodeVFD Wristwatch

Not just another steampunk fashion statement, [Johngineer's] ChronodeVFD wristwatch is as intricate as it is beautiful. Sure, we’ve seen our share of VFD builds (and if you want a crash course in vacuum fluorescent displays, check out Fran’s video from earlier this year) but we seldom see them as portable timepieces, much less ones this striking.

The ChronodeVFD uses a IVL2-7/5 display tube, which in addition to being small and low-current is also flat rather than rounded, and features a transparent backing. [Johngineer] made a custom board based around an AtMega88 and a Maxim DS3231 RTC (real time clock): the latter he admits is a bit expensive, but no one complains about left-overs that simplify your design.

The VFD runs off a Maxim MAX6920 12-bit shift register and is powered by a single alkaline AA battery. A rechargable NiMH would have been preferable, but the lower nominal voltage meant lower efficiency for his boost converters and less current for the VFD. [Johngineer] won’t get much more than 6-10 hours of life, but ultimately the ChronodeVFD is a costume piece not meant for daily wear. Swing by his blog for a number of high-res photos and further details on how he built the brass tubing “roll cage” enclosure as well as the mounts for the leather strap.

Dottie the Flip Dot Clock

What is it that we like so much about inefficient, noisy clocks made with inappropriate technology? Answer the question for yourself by watching the video (below) that [David Henshaw] sent us of Dottie, the flip-dot clock.

But besides the piece itself, we really like the progression in the build log, from “how am I going to do this?” to a boxed-up, finished project.

Another stunning aspect of this build is just how nice an acrylic case and a raft of cleverly written software can make a project look. You’d never guess from the front that the back-side was an (incredible) rat’s nest of breadboards and Ethernet wires. Those random switching patterns make you forget all the wiring.

And the servo-steered, solenoid-driven chimes are simply sweet. We’re sure that we’d love to hear them in real life.

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Hacklet 18 – Tick Tock, it’s Time for Clocks

18

In three words, Hackers love clocks. Not only do we think that digital watches are still a pretty neat idea, we love all manner of timepieces. This episode of The Hacklet focuses on the clock projects we’ve found over on Hackaday.io.

xkcdHardwareWe start with [rawe] and [tabascoeye], who both put the famous XKCD “now” clock into hardware. [tabascoeye] used a stepper motor in his xkcd world clock. [rawe] didn’t have any steppers handy, so he grabbed a cheap wall clock from Ikea for his xkcd.com/now clock in hardware. The now clock needs a 24 hour movement. Ikea only sells 12 hour movements, so [rawe] hacked in a 555 and some logic to divide the clock’s crystal by two. He’s currently using an EEVblog uCurrent to verify his modified clockwork consumes about half a milliwatt.

touchscreenclockNext up is [Craig Bonsignore] and his Touchscreen Alarm Clock. [Craig] got sick of store-bought alarm clocks, so he built his own. Then he modified it, added a few features, and kept building! The current incarnation of the clock has a pretty novel interface: a touchscreen over a bicolor LED matrix. The rest of the clock consists of an Arduino, an Adafruit Wave shield, and a Macetech Chronodot. [Craig] is currently mashing up these open source designs and building a single Arduino shield for his clock.

irisledclock[Warren Janssens] took the minimalist route with The Iris Clock. Iris is a ring of WS2812 RGB LEDs. The LEDs are mounted behind a wall colored piece of wood in such a way that you can only see their glow on the clock frame and the wall beyond it. This helps a with the eye searing effect WS2812s can have when viewed directly – even when dimmed with PWM. The code is mainly C with some AVR assembly thrown in to control the LEDs. [Warren] has given Iris 8 different time modes, from hour/minute/second to percentage of day with sunrise and sunset markers. With so many modes, the only hard part is knowing how to read the time Iris is displaying!

stargate[David Hopkins] also built a ring clock. His Stargate LED Clock not only tells time, but is a great replica of the Stargate from the TV series. [David] used four Adafruit WS2812 Neopixel segments to build a full 60 RGB LED ring. The Stargate runs on an Arduino nano with a real-time clock chip to keep accurate time. A photoresistor allows the Stargate to automatically dim at night. With some slick programming [David] added everything from a visual hourly “chime” to a smooth fade from LED to LED.

bendulum[dehne1] gives us something completely different with The Bendulum Clock. A bendulum is [dehne1's] own creation consisting of an inverted pendulum built without a pivot. The inverted pendulum swings by bending along its length. In [dehne1's] design, the bendulum is made out of a spring steel strip rescued from a car windshield wiper. The Bendulum doesn’t have a mechanical escapement, but an electromagnet sensed and driven by an Arduino. The amazing part of this project is that  [dehne1] isn’t using a real-time clock chip. The standard 8MHz Arduino resonator is calibrated over various temperatures, then used to calibrate the bendulum itself. The result is a clock that can be accurate within 1 minute each day. [dehne1] mounted his clock inside a custom wood case. We think it looks great, and want one for Hackaday HQ!

We’ve used enough clock ticks for this episode of The Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Still want more? Check out our Timepiece List!

Joule Thief Steals Power for a Clock

A common project among electronics tinkerers is the joule thief, a self-oscillating circuit that can “steal” the remaining energy in a battery after the voltage has dropped so low that most devices would stop working. Typically the circuit powers an LED until almost all of the energy is extracted from the battery, but [Lionel Sears] has created a specialized joule theif that uses the “extra” energy to power a clock.

The circuit uses four coils instead of the usual two to extract energy from the battery. The circuit charges a large capacitor which provides the higher current pulses needed to drive the clock’s mechanism. It can power the clock from a single AA battery, and will run until the voltage on the battery is only 0.5 volts.

Normally the clock would stop running well before the voltage drops this low, despite the fact that there’s still a little chemical energy left in the batteries. The circuit can drive the clock for an extended time with a new battery, or could use old “dead” batteries to run the clock for a brief time while the final little bit of energy is drawn from them. If you’re so inclined, you could even use hot and cold water with a joule thief to run your clock! Thanks to [Steven] for the tip.

Exposed Clock is Flippin’ Cool

Some hacks are triumphs of cleverness, others…are just cool. [Super Cameraman's] exposed retro flip clock tends toward the latter half of that spectrum—it may not be the most complex, but we’re relieved that for once there isn’t an Arduino crammed into the back of it.

You can buy pared down, exposed flip clocks at museums for an arm and a leg, or you can trudge through eBay and local thrift shops until you come across a cheapo clock radio. [Super Cameraman's] clock cost him exactly $2, and is split into two sections: a clock side and a radio side. Prying off the knobs and popping open the case reveals all the shiny mechanisms and electronics, most of which he trashed. The radio and even the transformer were removed, leaving only the flip clock, which he re-wired directly to the plug—it seems these types of clocks run straight off 120VAC. Check out the video below.

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