clock

568 Articles

Synesthetic Clock Doesn’t Require Synesthesia

April 10, 2024 by 14 Comments

We often think of synesthetes as those people who associate say, colors with numbers. But the phenomenon can occur with any of the senses. Simply put, when one sense is activated, synesthesia causes one to experience an unrelated, activated sense. Sounds trippy, no?

Thankfully, [Markus Opitz]’s synesthetic clock doesn’t require one to have synesthesia. It’s actually quite easy to read, we think. Can you tell what time it is in the image above? The only real requirement seems to be knowing the AM color from the PM color. The minute display cycles through blue, green, yellow, and red as the hour progresses.

Behind that pair of GC9a01 round displays lies an ESP32 and a real-time clock module. [Markus] couldn’t find a fillArc function, so instead he is drawing triangles whose ends lie outside the visible area. To calculate the size of the triangle, [Markus] is using the angle function tangent, so each minute has an angle of 6°.

[Markus] created a simple but attractive oak housing for the clock, but suggests anything from cardboard and plastic to a book. What’s the most interesting thing you’ve ever used for an enclosure? Let us know in the comments.

Do you appreciate a good analog clock when you see one? Here’s a clock that uses analog meters for its display.

Video Killed The Radio Alarm Clock

March 29, 2024 by 4 Comments

For decades now, MTV has been on a bizarre trajectory given its original name was an acronym for Music Television. In the original days in the 80s and 90s it kept mostly true to its name, but starting around two decades ago they expanded into reality and other non-musical television programming and have now left it largely behind. Plenty of those who grew up in its heyday have an understandable amount of nostalgia for the channel as a cultural touchstone, and [Derf] used MTV archival footage to build a video alarm clock which helps him keep in tune with the past.

To keep the appropriate 80s aesthetic, the build uses a portable TV from the late 80s with its original CRT. The video files are hosted on more modern technology though, in this case a Raspberry Pi. The Pi is set up to run a python script which launches the VLC media player with a playlist loaded with video files, in this case a long list of MTV shows. Some configuration needs to be done to get it to output to the old CRT properly which depends on the hardware used, but once that’s in place it’s ready to be used as an alarm. [Derf] is using a smart outlet to power the TV at the appropriate time, and a cron job which starts the video player simultaneously at a somewhat random point in the playlist.

As far as retro TVs go, having one as an alarm clock is certainly a novel idea. We have seen a few others in the past, though, one to play the golden age of The Simpsons, and another that recreates the nostalgia of 90s cable television complete with a preview channel and era-appropriate commercials.

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Saving A Clock Radio With An LM8562

March 28, 2024 by 10 Comments

Smart phones have taken the place of a lot of different devices especially as they get more and more powerful. GPS, music and video player, email, and of course a phone are all functions tied up in these general-purpose devices. Another casualty of the smart phone revolution is the humble bedside alarm clock as its radio, alarm, and timekeeping functionalities are also provided by modern devices. [zst123] has a sentimental attachment to the one he used in the 00s, though, and set about restoring it to its former glory.

Most of the issue with the clock involved drift with the timekeeping circuitry. Since it wasn’t accurately keeping the time anymore, losing around 10 minutes a day, the goal to save it was to use NTP to get the current time and a microcontroller to make the correction automatically. Rather than replace everything in the clock except the display, [zst123] is using the existing circuit board and adding an ESP8266 to grab the time from the Internet. A custom driver board reads the current time displayed on the clock directly from the display itself and then the ESP8266 can adjust it by using the existing buttons through a relay wired in parallel.

Using the existing circuitry was certainly a challenge especially since the display was multiplexed, but the LM8562 that came with these clock radios is a common and well-documented chip for driving displays like this, giving [zst123] a leg up over something unlabeled or proprietary. Using NTP is certainly a reliable and straightforward way of getting the current time too but there are a few other options for projects like these like using GPS or even a radio signal.

Simple NTP Clock Uses Custom RGB 7-Segment Displays

March 17, 2024 by 15 Comments

A great majority of hackers build a clock at some point. It’s a great way to get familiar with electronics and (often) microcontrollers, and you get to express some creativity along the way. Plus, you get something useful when you’re done! [Tadas Ustinavičius] recently trod this well-worn path and built a neat little NTP clock of their own.

The build uses an ESP 12F as the core of the operation. It’s charged with querying an NTP time server via its WiFi connection in order to maintain accurate timekeeping around the clock. For display, it drives a series of custom 7-segment displays that [Tadas] built using 3D-printed housings. They use WS2812B addressable LEDs and thus can display a rainbow of colors.

For initial configuration, the phone creates its own WiFi hotspot with a web interface for changing settings. Once configured, it connects to the Internet over WiFi to query an NTP server at regular intervals.

It’s a simple build that does a simple job well. Projects like these can be very valuable, as they teach you all kinds of useful skills. If you’ve been working on your own clock design, don’t hesitate to let us know. You can use a microcontroller, relays, or even a ball.

The Perils Of Return Path Gaps

March 15, 2024 by 9 Comments

The radio frequency world is full of mysteries, some of which seem to take a lifetime to master. And even then, it seems like there’s always something more to learn, and some new subtlety that can turn a good design on paper into a nightmare of unwanted interference and unexpected consequences in the real world.

As [Ken Wyatt] aptly demonstrates in the video below, where you put gaps in return paths on a PCB is one way to really screw things up. His demo system is simple: a pair of insulated wires running from the center pins on BNC jacks and running along the surface of a piece of copper-clad board to simulate a PCB trace. The end of each wire is connected to the board’s ground plane through a 50 ohm resistor, with one wire running over a narrow slot cut into the board. A harmonics-rich signal is fed into each trace while an H-field EMC probe connected to a spectrum analyzer is run along the length of the trace.

With the trace running over the solid ground plane, the harmonics are plentiful, as expected, but they fall off very quickly away from the trace. But over on the trace with the gapped return trace it’s a far different story. The harmonics are still there, but they’re about 5 dBmV higher in the vicinity of the gap. [Ken] also uses the probe to show just how far from the signal trace the return path extends to get around the gap. And even worse, the gap makes it so that harmonics are detectable on the unpowered trace. He also uses a current probe to show how common-mode current will radiate from a long conductor attached to the backplane, and that it’s about 20 dB higher with the gapped trace.

Hats off to [Ken] for this simple explanation and vivid reminder to watch return paths on clock traces and other high-frequency signals. Need an EMC probe to check your work? A bit of rigid coax and an SDR are all you need.  Continue reading “The Perils Of Return Path Gaps” →

Educational Arduino Clock Uses Analog Meters For Display

March 1, 2024 by 13 Comments

When it comes to educational electronic projects, it’s hard to go past building a clock. You learn tons about everything from circuit concepts and assembly skills to insights about the very nature of time itself. And you get a clock at the end of it! [hamblin.joe] wanted to do a simple project for kids along these lines, so whipped up a neat design using analog meters to display the time.

The build relies on that old stalwart, the Arduino Uno, to run the show. It’s hooked up to a DS3231 real-time clock module so it can keep accurate time for long periods, as is befitting a clock. Displaying the time is done via the use of two analog meters, each fitted with a custom backing card. One displays hours, the other, minutes. The analog meters are simply driven by the PWM outputs of the Arduino.

It’s not a hugely complex project, but it teaches so much. It provides an opportunity to educate the builders about real-time clocks, microcontroller programming, and even the concepts behind pulse width modulation. To say nothing of the physical skills, like learning to solder or how to assemble the laser-cut enclosure. Ultimately, it looks like a really great way for [hamblin.joe] and his students to dive into the world of modern electronics.

Pi Pico Enhances RadioShack Computer Kit

February 20, 2024 by 9 Comments

While most of us now remember Radio Shack as a store that tried to force us to buy batteries and cell phones whenever we went to buy a few transistors and other circuit components, for a time it was an innovative and valuable store for electronics enthusiasts before it began its long demise. Among other electronics and radio parts and kits there were even a few DIY microcomputers, and even though it’s a bit of an antique now a Raspberry Pi Pico is just the thing to modernize this Radio Shack vintage microcomputer kit from the mid 80s.

The microcomputer kit itself is built around the 4-bit Texas Instruments TMS1100, one of the first mass-produced microcontrollers. The kit makes the processor’s functionality more readily available to the user, with a keypad and various switches for programming and a number of status LEDs to monitor its state. The Pi Pico comes into the equation programmed to act as a digital clock with an LED display to drive the antique computer. The Pi then sends a switching pulse through a relay to the microcomputer, which is programmed as a binary counter.

While the microcomputer isn’t going to win any speed or processing power anytime soon, especially with its clock signal coming from a slow relay module, the computer itself is still fulfilling its purpose as an educational tool despite being nearly four decades old. With the slow clock speeds it’s much more intuitive how the computer is stepping through its tasks, and the modern Pi Pico helps it with its tasks quite well. Relays on their own can be a substitute for the entire microcontroller as well, like this computer which has a satisfying mechanical noise when it’s running a program.

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