Author: Bryan Cockfield

1778 Articles

Analog Video From An 8-Bit Microcontroller

March 21, 2026 by 6 Comments

Although the CRT has largely disappeared from our everyday lives, there was a decades-long timeframe when this was effectively the only display available. It’s an analog display for an analog world, and now that almost everything electronic is digital, these amazing pieces of technology are largely relegated to retro gaming and a few other niche uses. [Maurycy] has a unique CRT that’s small enough to fit in a handheld television, but since there aren’t analog TV stations anymore, he decided to build his own with nothing but an 8-bit microcontroller and a few other small parts.

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Analog Siren For Psychedelic Soundscapes

March 21, 2026 by 2 Comments

For better or worse, there are a few instruments that have been pigeonholed into specific genres of popular music. For example, banjos are often heard in bluegrass or folk, harmonicas in blues, and a sick horn section will take many of us immediately to third wave ska. Similarly, there are certain styles of synthesizers tied to various genres and if you’re a fan a certain sub-genre of reggae you’ll be familiar with the dub siren. This unique analog synth has a few tricks up its sleeve and [Jakub] shows us how he built his.

He’s calling this build the Sirenotron, and its based on the venerable 555 timer It also features an LFO built on an LM358, with triangle and square wave modes, plus an additional “acid mode” for the square wave which adds a single capacitor to the circuit but makes a big difference in the sound. Like any siren synth, there are potentiometers to control pitch and the pulse rate of the siren as well and another switch controls whether it is outputting sound or not. He’s also included the ability to control it with a foot pedal so he can use it while playing the bass guitar during live shows.

[Jakub] has gone through several prototypes before getting to this stage, and not only uses it when playing dub but also creates psychedelic soundscapes in a side project of his where it also fits right in. He’s also made the schematics available for anyone who wants to reproduce it or build on his design.

We’re always interested in a unique synthesizer build around here, and some of our favorites include this synth built from Sega Genesis parts and this one controlled more like a woodwind instrument.

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3D Printed Clock Just Taps It In

March 21, 2026 by 4 Comments

The famous cuckoo clock, with its moving, chirping mechanical bird indicating various divisions of time, has been around since at least the 1600s. The most famous of them come from the Black Forest area of Germany, and are still being made worldwide even today. Other clocks with different themes take their inspiration from the standard bird-based clocks from history, and thanks to modern 3D printing and other technologies we can make clocks with almost any type of hour indicator we’d like with relative ease like [Jason]’s golf clock.

While the timekeeping mechanism is a fairly standard analog clock, the hour indicator mechanism in this build is a small figure which putts a golf ball into a hole once every hour. It uses an ESP32-C3 at its core, which controls a pair of servos. One controls the miniature golfer, and the other lifts the ball up into position on the green at the appointed time. Once the ball is in place, the figure rotates, striking the ball towards the hole. Although it looks almost like the ball is guided by a magnet of some sort at first glance, the ball naturally finds its way into the hole by the topography of the green alone.

Almost all of the parts in this build are 3D printed, including the green, the golfer, the frame, and a number of the servo components. There’s also a small sensor that detects if the ball has actually made it into the hole and back to the lifting mechanism, and to that end there’s also a number of configurations that can be made in the software to ensure that the servos controlling everything all work together to putt the ball properly.

While not a cuckoo clock in the strict sense, we always appreciate a unique clock around here, but if you demand your clocks have ideological purity we’ll point you to this cuckoo clock built into a wristwatch.

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Real Robot Makes Debut In Programming Game

March 19, 2026 by 1 Comment

Sometimes the right tool for the right job appears almost out of nowhere. That was certainly the case for [Jonathan] who came across an unusual but well-designed robot at a secondhand shop. The robot needed a bit of work to get back into a usable condition, but after that it was ready for use. For such a unique machine, it needed a unique place to work as well, so in this build [Jonathan] uses it as a real robot to recreate a popular board game meant to teach programming to children.

In the original board game, called Robot Turtles, there are no actual robots. Instead, players use cards to control turtles to reach objectives in much the same way that a programmer would solve a similar problem with a computer. A board game with such a name almost demands a robot, so [Jonathan] found a larger playing surface in the form of soft matting blocks, each with a number or letter, that can be assembled into a grid. To make the game, he built a Python application on top of the interface he reverse-engineered in a previous build. It handles the robot interface, control, input, and a PyGame GUI. The game can either be played in real-time, or the robot’s moves can be queued.

In addition to keyboard input, the bot can also be controlled by putting cards from the actual board game itself on an NFC reader he made. [Jonathan] has a four-year-old at home, so he hopes that all of these projects will have an impression and encourage experimentation and discovery of computers and programming.

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Off-Grid Electricity And Hot Water From Scrap Wood

March 14, 2026 by 41 Comments

Cooking with charcoal is a fairly common human activity, as much as others have come to prefer fuels like propane and propane accessories for their outdoor, summertime grilling. Although it’s made from wood, it has properties that make it much more useful for cooking — including burning at a higher temperature and with more consistent burn rates. It can also be used as a fuel for generating heat and electricity, but since it’s not typically found lying around in the forest it has to be produced, which [Greenhill Forge] has demonstrated his charcoal production system in one of his latest videos.

The process for creating charcoal is fairly simple. All that needs to happen is for wood to be heated beyond a certain temperature in the absence of oxygen. At this point it will off-gas the water stored in it as well as some of the volatile organic compounds, and what’s left behind is a flammable carbon residue. Those volatile organics are flammable as well, though, so [Greenhill Forge] uses them to heat the wood in a self-sustaining reaction. First, a metal retort is constructed from a metal ammo box, with a pipe extending from the side and then underneath the box. A few holes are drilled in this part, and the apparatus is mounted above a small fire on a metal stand. With the fire lit the wood begins heating, and as it heats these compounds exit the pipe and ignite, adding further fuel to the fire. Eventually the small fire will go out, allowing the retort to heat itself on the gasses released from the wood alone.

To generate the hot water, [Greenhill Forge] has taken an extra step and enclosed the retort in a double walled metal cylinder. Inside the cylinder is a copper tube packed in sand, which harvests the waste heat from the charcoal production for hot water. In his test runs, the water in a large drum was heated to the point that the tubing he used for the test began to melt, so it is certainly working better than he expected.

After the retort cools, [Greenhill Forge] uses the charcoal in another process that generates about a days’ worth of electricity and hot water. It’s part of a complete off-grid system that’s fairly carbon neutral, since trees are an abundant renewable resource compared to fossil fuels. Heating with wood directly is still common in many cold areas around the world, with the one major downside being the labor required to keep the stove running. But we’ve seen at least one project which solves this problem as well.

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One Sailing Pulley To Rule Them All

March 6, 2026 by 25 Comments

When thinking of humanity’s ability to harness wind energy, many people will conjure images of windmills from places like The Netherlands or Persia. But people have been using wind energy for far longer than that in the form of sailing ships. Using the wind for transportation goes back another four thousand years or so, but despite our vast experience navigating the seas with wind alone there is still some room for improvement. Many modern sailboats use a number of different pulleys to manage all of the rigging, but this new, open-source pulley can replace many of them.

The pulley, or “block” as they are sometimes called, is built with a polymer roller made out of a type of nylon, which has the benefit of being extremely durable and self-lubricating but is a bit expensive. Durability and lack of squeakiness is important in sailing applications, though. The body is made from CNC-machined aluminum and is composed of two parts, which pivot around the pulley’s axis to allow various ropes (or “lines”) to be inserted without freeing one end of the rope. In testing, this design outperformed some proprietary stainless steel pulleys of similar size.

Another perk of this design is that it can be set up to work in many different applications on a sailboat, whether that’s for hoisting a mainsail or pulling in a jib or any other task a pulley could be used for. It can also be stacked with others in many different configurations to build custom pulleys of almost any type, and can support up to 14 mm lines. For a sailor this could be extremely valuable, because as it stands each pulley on a ship tends to be used in only certain applications, and might also be proprietary from a specific company. This pulley is being released into the open-source world, allowing anyone to create them who wants one.

Thanks to [Keith] for the tip!

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Portable Tow Rope Batman Would Be Proud Of

March 6, 2026 by 16 Comments

Out of all of Batman’s massive array of tools which turn a relatively ordinary person into a superhero, perhaps his most utilitarian is his grappling gun — allowing him the ability to soar around his city like Spiderman or Superman. [John Boss] isn’t typically fighting crime, but he did develop his own grappling gun of sorts which gives him another superpower: the ability to easily scale snowy hills to quickly get back to the top.

The grappling gun takes inspiration from a commonly used tool called a power ascender, which is often used in industry applications where climbing is required. This one is held in the hand and uses a brushless motor with a belt-driven 3:1 reduction for increased torque. The pulley system, bearings, and motor are all housed in a 3D printed enclosure and are powered by rechargeable Milwaukee power tool batteries. During prototyping the rope intake and output feed locations had to be moved to increase the pulley’s grabbing ability, and with a working prototype he swapped a lot of the plastic 3D printed parts out for metal to increase the sturdiness of the device.

The grappling gun was originally designed for a smaller child to get hoisted up a hill on a sled, but when stress testing the device [John] found out that it actually has more than enough capability to haul even an adult up a hill on skis. As an added bonus, the outfeed for the rope can be put into a bag and used to automatically coil the rope up when he’s done at the hill. Although this is a great solution for a portable rope tow, for something more permanent and more powerful take a look at this backyard rope tow that was built from spare parts.

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