Discrete-Logic UART Keeps 8-Bit TTL Computer Connected

August 26, 2020 by Dan Maloney 18 Comments

Pity the poor TTL computer aficionado. It’s an obsession, really — using discrete logic chips to scratch-build a computer that would probably compare unfavorably to an 80s era 8-bit machine in terms of performance. And yet they still forge ahead with their breadboards full of chips and tangles of wire. It’s really quite beautiful when you think about it.

[Duncan] at Shepherding Electrons has caught the TTL bug, and while building his 8-bit machine outfitted it with this discrete logic UART. The universal asynchronous receiver-transmitter is such a useful thing that single-chip versions of the device have been available since the early 1970s. [Duncan]’s version makes the magic of serial communications happen in just 12 chips, all from the 74LS logic family.

As if the feat of building a discrete logic UART weren’t enough, [Duncan] pulled this off without the aid of an oscilloscope. Debugging was a matter of substituting the 2.4576 MHz crystal oscillator clock with a simple 1 Hz 555 timer circuit; the reduced clock speed made it easier to check voltages and monitor the status of lines with LEDs. Once the circuit was working, the full-speed clock was substituted back in, allowing him to talk to his 8-bit computer at up to 38,400 bps. Color us impressed.

For more TTL computer goodness, and to see where [Duncan] got his inspiration, check out [Ben Eater]’s many discrete logic projects — his scratch-built 6502, a low-end video card, or even his take on serial communications.

Moving Fridge Magnets Make For Unique Clock

August 14, 2020 by Dan Maloney 40 Comments

We see a ton of clock projects around these parts, and being hackers, we love to feature them all. But every once in a while we stumble upon a great new way to display the time that really gets our attention and requires a closer look, such as this moving fridge magnet clock.

The fridge magnets [Craig Colvin] built this unique clock around are the colorful plastic kinds that have adorned the lower regions of refrigerators in toddler-filled households for ages. Instead of residing on a fridge, [Craig] laminated a sheet of white acrylic to a thin sheet of steel, to give the magnets something to hold onto. Moving the numbers is the job of a CoreXY-style mechanism. The belt-driven Cartesian movement maneuvers a head to to the right location to pick up a number; a servo in the head moves two powerful magnets into position under the number. The head then moves the number to the right spot, releases its magnets, and the number stays put on the board. You can see it in action in the video after the break.

While we love this as it is, it brings to mind some great mods. One can imagine the addition of letters to make a legit word clock, or to just add a calendar display. We’d also love to see these magnets in their natural habitat by building this into the door of a working fridge.

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Animal Crossing IRL With Nova Lights To Mark The Passage Of Time

August 8, 2020 by Jenny List 1 Comment

We feature a lot of clocks here at Hackaday, but it’s not often that one comes along and makes us stop in our tracks and reconsider the fundamental question: just what is a clock? [Charlyn] has managed it though, with her Nova Light clock, which doesn’t so much measure the passing of time, but mark it.

The clock itself is a set of origami pieces in the shape of the Nova lights and a star fragment from the popular Animal Crossing New Horizons game, and each has a multicolour LED underneath. The star fragment pulses, while the two Nova lights imperceptibly slowly change colour, one over the course of the day and the other over the course of the week. Except for Fridays, when in celebration of the end of the work week they pulsate with different colours. Under the hood is an Adafruit Feather with a real-time clock module, and since all the code is there for your enjoyment you can have a go at making your own. Below the break is a video showing the clock in action.

[Charlyn] is no stranger to these pages, in fact we’ve featured her exquisite use of origami before. It’s probably her rideable rocking horse that’s the most memorable among her projects though.

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Do You Know Where Your Children Are? Check The Weasley Clock

July 29, 2020 by Kristina Panos 16 Comments

What’s the coolest thing you could build for a Harry Potter fan, aside from a working magic wand or Quidditch broomstick? We would have to say a Weasley clock that shows the whereabouts of everyone in the family is pretty high on the list, especially if that fan is a wife and mother.

Here’s how it works: they’ve set up geofences to define the boundaries of home, each person’s school or workplace, and so on. The family’s locations are tracked through their phones’ GPS using Home Assistant, which is hosted on a Raspberry Pi. Whenever someone’s location changes, the Pi alerts the clock over MQTT, and it moves the 3D-printed hands with servos.

The clock has some interesting granularity to it as well. As someone gets closer to home, their pointer’s distance reflects that in its proximity to the Home slice. And Home itself is divided into the main house and the shop and reflected by the pointer’s position.

We particularly like the attention to detail here, like the art poster used for the clock’s face that includes all the Weasley’s whereabouts in the background. It’s built into a thrift store grandmother clock, which is smaller than a grandfather clock but no less majestic. In the future there are plans to implement the clock’s chimes to announce that someone is back home.

No matter what you’re into, the whereabouts clock idea can probably fit that universe. For instance, here’s one that uses LEGO mini-fig heads to locate roommates.

Hex Matrix Clock Is Spellbinding

July 26, 2020 by Kristina Panos 8 Comments

Just when we think we’ve seen all possible combinations of 3D printing, microcontrollers, and pretty blinkenlights coming together to form DIY clocks, [Mukesh_Sankhla] goes and builds this geometric beauty. It’s kaleidoscopic, it’s mosaic, and it sorta resembles stained glass, but is way cheaper and easier.

The crucial part of the print does two jobs — it combines a plate full of holes for a string of addressable RGB LEDs with the light-dividing walls that turn the LEDs into triangular pixels. [Mukesh] designed digits for a clock that each use ten triangles. You’d need an ESP8266 to run the clock code, or if you’d rather sit and admire the rainbow light show unabated by the passing of time, just use an Arduino Uno or something similar.

Most of the aesthetic magic here is in the printed pieces and the FastLED library. It has a bunch of really cool animations baked in that look great with this design. Check out the demo video after the break. The audio is really quiet until the very end of the video, so be warned. In our opinion, the audio isn’t necessary to follow along with the build.

The humble clock takes many lovely forms around here, including pop art.

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384 Neon Bulbs Become Attractive Display

July 23, 2020 by Lewin Day 11 Comments

Neon lights have inspired much prose over the years, with their attractive light output receiving glowing adulation. [Pierre Muth] is a big fan, and decided to spend lockdown creating something suitably pretty for his desk.

An 8×8 segment of the total panel. The display draws 40W at 5V with all pixels on at the same time.

The project consists of an 8×48 matrix display constructed out of INS-1 (ИНC-1) tubes. These tiny neon tubes are 6.5 mm in diameter, showing a bright orange dot of light when powered up. Requiring just 100 V and 0.5 mA to light, they’re a touch easier to drive than the famous Nixie.

[Pierre] decided to go all out, wishing to replicate the capabilities of smart LEDs like the WS2812. These contain a microcontroller built in to each LED, so [Pierre] would have to do the same. Each of the 384 neon tubes got its own bespoke PCB, containing a PIC16F15313 microcontroller, step up voltage circuitry, and a 6-pin connector. (Whoah!) When each bulb was soldered to its PCB, they were then plugged into a backplane. An ESP32 was then employed to drive the display as a whole.

Creating a display in this fashion takes a huge amount of work, with most of it being soldering the 384 individual bulb PCBs containing 11 components each. We have a lot of respect for [Pierre]’s work ethic to get this done during lockdown, and the final result is a gloriously retro neon matrix display. We’ve featured other neon matrixes recently, too. Video after the break. Continue reading “384 Neon Bulbs Become Attractive Display” →

It’s Time For Watch Clocks To Make A Comeback

July 10, 2020 by Kristina Panos 10 Comments

Along with all the colorful, geometric influence of Memphis design everywhere, giant wristwatch clocks were one of our favorite things about the 80s. We always wanted one, and frankly, we still do. Evidently, so did [Kothe]. But instead of some splashy Swatch-esque style, [Kothe] went the nerdy route by building a giant Casio F-91W to hang on the wall.

Not only does it look fantastic, it has the full functionality of the original from the alarm to the stopwatch to the backlit screen. Well, everything but the water resistance. The case is 3D-printed, as are the buckle and the buttons. [Kothe] might have printed the straps, but they were too big for the bed. Instead, they are made of laser-cut foam and engraved with all the details.

Inside there’s a 7″ touch display, a real-time clock module, and an Arduino Mega to make everything tick. To make each of the printed buttons work, [Kothe] cleverly extended a touch sensor module’s input pad with some copper tape. We think this could only be more awesome if it were modeled after one of Casio’s calculator watches, but that might be asking too much. Take a few seconds to watch the demo after the break.

Prefer your clocks less clock-like? Get a handle on the inner workings of this slot machine-based stunner.

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