Candle clocks were once an easy way to build a clock without using complex mechanical devices: just observe how quickly a thin candle burns down, mark an identical candle with periodic gradations, and you had a simple timer. These were the first candle-based timekeeping devices, but as [Tim]’s flicker-based oscillator demonstrates, they’re certainly not the […]
How fast does your heart beat? It’s a tough question to answer, because our heart rate changes all the time depending on what we’re doing and how our body is behaving. However, [Ludwin] noted that resting heart rates often settle somewhere near 60 bpm on average. Thus, they entered a heart rate sensor to our […]
If you want to blink an LED once every second, you could use just about any old timer circuit to create a 1 Hz signal. Or, you could go the complicated route like [Anthony Vincz] and grab 1 Hz off a radio clock instead. The build is an entry for the 2025 One Hertz Challenge, […]
The 2025 One Hertz Challenge asks you to build a project that does something once every second. While that has inspired a lot of clock and timekeeping builds, we’re also seeing some that do entirely different things on a 1 Hz period. [junkdust] has entered the contest with a project that does something rather mathematical […]
The 2025 One Hertz Challenge is really heating up with all kinds of projects that do something once every second. [The Baiko] has given us a rather abstract entry that looks like a plane…if you squint at it under the right conditions. It’s actually quite an amusing abstract build. If you’ve ever seen planes flying […]
These days, if you want to flash some LEDs, you’d probably grab a microcontroller. Maybe you’d go a little more old-school, and grab a 555. However, [Jacob] is even more hardcore than that, as evidenced by this chunky electromechanical flasher build. [Jacob] goes into great detail on his ancillary write-up, describing how the simple building […]
Like many early microcomputers, the Commodore VIC-20 did not come with an interna real-time clock built into the system. [David Hunter] has seen fit to rectify that with an add-on module as his entry to the 2025 One Hertz Challenge. [David]’s project was inspired by a product that Hayes produced in the 1980s, which provided […]
Let’s say you want to build a Nixie clock. You could go out and find some tubes, source a good power supply design, start whipping up a PCB, and working on a custom enclosure. Or, you could skip all that, and just follow [Simon]’s example instead. The trick to building a Nixie clock fast is […]
On an old fashioned bench a signal generator was once an indispensable instrument, but has now largely been supplanted by the more versatile function generator. Sometimes there’s a less demanding need for a clock signal though, and one way that might be served comes from [Rupin Chheda]’s square wave generator. It’s a small PCB designed […]
Entries keep ticking in for the One Hertz Challenge, some more practical than others. [Pierre-Loup M.]’s One Hertz Sculpture has no pretensions of being anything but pretty, but we can absolutely respect the artistic impulse behind it. The sculpture is a free-form circuit inside of a picture frame. There are 9 LEDs in a ring […]