A High Resolution ADC From Scratch

It’s a well-known conundrum that while most computers these days are digital in nature, almost nothing in nature is. Most things we encounter in the real world, whether it’s temperature, time, sound, pressure, or any other measurable phenomenon comes to us in analog form. To convert these signals to something understandable by a digital converter we need an analog-to-digital converter or ADC, and [Igor] has built a unique one from scratch called a delta sigma converter.

What separates delta sigma converters apart is their high sampling rate combined with a clever way of averaging the measurements to get a very precise final value. In [Igor]’s version this average is provided by an op-amp that integrates the input signal and a feedback signal, allowing for an extremely precise digital value to be outputted at the end of the conversion process. [Igor] has built this one from scratch as well, and is using it to interface a magnetic rotary encoder to control digital audio playback.

Although he has this set up with specific hardware, he has enough detail in his video (including timing diagrams and explanations of all of the theory behind these circuits) for anyone else to build one of these for other means, and it should be easily adaptable for plenty of uses. There are plenty of different ADC topologies too, and we saw many different ones a few years ago during our op-amp challenge.

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Build A 3D Printed Tide Clock So You Know When The Sea Is Coming To Get You

The tides! Such a unique thing, because on Earth, we don’t just have oceans full of liquid water—we also have a big ol’ moon called Moon to pull them around. You might like to keep track of the tides; if so, this tide clock from [rabbitcreek] could come in handy.

The motions of the tides are moderately complex; it was in the late 19th century that Sir William Thomson figured out a reasonable method to predict the tides mathematically and with a mechanical contrivance of his own design. These days, though, you don’t need pulleys and ropes to build a tide clock; you can just use electronics for display and the NOAA API to get the information you need.

[rabbitcreek’s] build is based around the Xiao ESP32 S3, which is charged with using its Wi-Fi connection to query NOAA up-to-date tide height data. It then uses this information to drive the position of a servo, installed inside a 3D-printed housing. The servo rotates a little red Moon indicator around a central Earth, with our home planet surrounded by a stretched blue marker indicating the swelling of the tides as influenced by the Moon’s gravity.

If you’re a surfer or beach driver that’s always wanting to know the tidal state at a glance, this clock is for you. We’ve featured other tide clocks before, but never any projects that can actually influence the tides themselves. If you’ve figured out how to mess with gravity on a planetary scale, consider applying for a Nobel Prize—but do notify the tipsline before you do.

Building A Desk Display For Time And Weather Data

Just about every laptop, desktop, and smartphone in your life can tell you the date, time, and current weather predictions. However, sometimes it’s nice to have simple data displayed on a bespoke device. That’s what inspired [Mario] to create ESPTimeCast. 

As you might have guessed by the name, the project is designed around the ESP32 and ESP8266 microcontrollers; either one is up to the task of running the show here. Both come with Wi-Fi connectivity out of the box, which makes it easy for them to hook up to the Internet to query NTP servers for the time and weather data from OpenWeatherMap. The data is then displayed on an LED matrix display, made up of four 8×8 LED modules and driven with the aid of the MAX7219 IC. Configuration is handled over a simple web interface hosted on the device itself. All the parts are wrapped up in a 3D-printed housing that would be very fitting in any home that appreciates the magic of late 60s/early 70s decor.

Hackers love building clocks, weather stations, and other useful information displays. We’ve seen a great many examples over the years. If you’re cooking up your own neat project in this area, don’t hesitate to let us know!

A Breadboard Computer In Three Chips

Building a computer on a breadboard is a seminal project for many builders, but it can become complicated quite quickly, not to mention that all the parts needed for a computer are being placed on a medium which often lends itself to loose wires and other hardware bugs. [3DSage] has a working breadboard computer that is as simple as it can possibly be, putting it together piece by piece to show exactly what’s needed to get a computer which can count, access memory, and even perform basic mathematical operations.

The first step for any computer is to build a clock, and in this case it’s being provided by a 555 timer which is configured to provide an adjustable time standard and which steps through the clock pulses when a button is pressed. The next piece is a four-bit counter and a memory chip, which lets the computer read and write data. A set of DIP switches allows a user to write data to memory, and by using the last three bits of the data as opcodes, the computer can reset, halt, and jump to various points in a simple program.

Although these three chips make it possible to perform basic programming, [3DSage] takes this a bit further in his video by demonstrating some other simple programs, such as one which can play music or behave as an alarm clock. He also shows how to use a fourth chip in the form of a binary adder to perform some basic math, and then packages it all into a retro-styled computer kit. Of course you can take these principles and build them out as far as they will go, like this full 8-bit computer built on a breadboard or even this breadboard computer that hosts a 486.

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Old Projects? Memorialize Them Into Functional Art

What does one do with old circuit boards and projects? Throwing them out doesn’t feel right, but storage space is at a premium for most of us. [Gregory Charvat] suggests doing what he did: combining them all into a wall-mountable panel in order to memorialize them, creating a functional digital clock in the process. As a side benefit, it frees up storage space!

Everything contributes. If it had lights, they light up. If it had a motor, it moves.

Memorializing and honoring his old hardware is a journey that involved more than just gluing components to a panel and hanging it on the wall. [Gregory] went through his old projects one by one, doing repairs where necessary and modifying as required to ensure that each unit could power up, and did something once it did. Composition-wise, earlier projects (some from childhood) are mounted near the bottom. The higher up on the panel, the more recent the project.

As mentioned, the whole panel is more than just a collage of vintage hardware — it functions as a digital clock, complete with seven-segment LED displays and a sheet metal panel festooned with salvaged controls. Behind it all, an Arduino MEGA takes care of running the show.

Creating it was clearly a nostalgic journey for [Gregory], resulting in a piece that celebrates and showcases his hardware work into something functional that seems to have a life of its own. You can get a closer look in the video embedded below the page break.

This really seems like a rewarding way to memorialize one’s old projects, and maybe even help let go of unfinished ones.

And of course, we’re also a fan of the way it frees up space. After all, many of us do not thrive in clutter and our own [Gerrit Coetzee] has some guidance and advice on controlling it.

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Candle Oscillator Really Heats Things Up

As the timebase for a clock, almost anything with a periodic oscillation can be used. Traditionally, that meant a pendulum, but in our time, we’ve seen plenty of others. Perhaps none as unusual as [Tim]’s candle flicker clock, though.

Candles are known for their flickering, a property of the wick and the fuel supply that candle manufacturers have gone to great lengths to mitigate. If you bring several of them together, they will have a significant flicker, with a surprisingly consistent 9.9 Hz frequency. This is the timebase for the clock, with the capacitance of the flame being sensed by a wire connected to a CH32 microcontroller, and processed to produce the required timing.

We like this project, and consider it a shame that it’s not an entry in our One Hertz Challenge.  Oddly, though, it’s not the first candle-based oscillator we’ve seen; they can even be turned into active electronic devices.

2025 One Hertz Challenge: Digital Clock Built With Analog Timer

You can use a microcontroller to build a clock. After all, a clock is just something that counts the passage of time. The only problem is that microcontrollers can’t track time very accurately. They need some kind of external timing source that doesn’t drift as much as the microcontroller’s primary clock oscillator. To that end, [Josh] wanted to try using a rather famous IC with his Arduino to build a viable timepiece.

[Josh]’s idea was straightforward—employ a 555 timer IC to generate a square wave at 1 Hz. He set up an Arduino Uno to count the pulses using edge detection. This allowed for a reliable count which would serve as the timebase for a simple 24-hour clock. The time was then displayed on an OLED display attached over I2C, while raw pulses from the 555 were counted on a 7-segment display as a useful debugging measure. Setting the time is easy, with a few pushbuttons hooked up to the Arduino for this purpose.

[Josh] claims a drift of “only ~0.5 seconds” but does not state over what time period this drift occurs. In any case, 555s are not really used for timekeeping purposes in this way, because timers based on resistor-capacitor circuits tend to drift a lot and are highly susceptible to temperature changes. However, [Josh] could easily turn this into a highly accurate clock merely by replacing the 555 square wave input with a 1PPS clock source from another type of timer or GPS device.

We’ve had quite a few clocks entered into the One Hertz Competition already, including this hilariously easy Nixie clock build. You’ve got until August 19 to get your own entry in, so wow us with your project that does something once a second!