Delta Pen Plotter Draws In Multiple Colors

July 26, 2026 by 2 Comments

If you’re building your first plotter, or you just like thinking in right angles, you’d probably consider a Cartesian design for your build. [András Vujovits] went another route with his project, building an impressive delta pen plotter with a useful tool changer, to boot.

The build relies on a unique motion system, wherein two NEMA 17 stepper motors drive either side of the linkage to control the position of the end effector—in this case, a pen carriage. By controlling the position of each side of the mechanism, it’s possible to move the pen through XY space. Running the show is an Arduino Nano, fitted with a GRBL shield and appropriate stepper motor drivers.

The magnetic tool changer is particularly nifty, too. It allows the plotter to grab a different ink at will to add more color to the drawing. It’s well-designed, with the plotter able to change inks without losing accuracy or otherwise fumbling the switchover. The plotter uses Muji ball point pens, which are available in a range of colors and draw with slick, clean lines. It’s also quite a fast plotter, thanks in part to [András]’s efforts to keep the pen carriage light by using a smart mechanism to offload the pen lifting actuator to the main body.

[András] has plans available, but you’re going to have to pay for them. Still, it’s always nice to see a new machine in the wild. Video after the break.

Continue reading “Delta Pen Plotter Draws In Multiple Colors” →

How Film Industry Data Website The-Numbers.com Got Mauled By Bots

July 25, 2026 by No comments

A lot has been made about the increase of automated traffic on the Internet, with the past years LLM-related crawlers having quite literally swarmed the picture here. Not only does this drive up traffic, it also increases load on web servers, whose owners find themselves faced with increased hosting costs. This recently led to The-Numbers.com going offline for a while as automated traffic was quite literally destroying their bottom line.

This saga is covered by [Stephen Follows], who had a chance to talk with the founder and CEO of the site, [Bruce Nash], after the site went basically offline for a few months. Since the website both licenses data for commercial purposes as well as offering the free access on its website, there were accusations of this being a ‘rug pull’.

The site was started in 1997, as a static HTML site on Geocities where [Bruce] provided box office analyses for investment purposes. Since that beginning traffic was generally polite, with human visitors and usually well-behaved search engine crawlers. Then around 2024 the first wave of scraper bots arrived, followed by a larger wave around December of 2025.

Despite implementing a few mitigations, such as LLM-targeted text, the increased traffic and the resulting load on a site architecture that was never designed for this ultimately led to a collapse. One of the major sources of traffic turned out to be from so-called ‘prediction markets’, like Polymarket, whose bots absolutely hammered the site.

Fortunately for [Bruce] and his team they do not rely on the free website for income, but they have had to massively rework the site’s architecture to bring back a semblance of the original features. As noted in the article, the amount of crawling traffic by these LLMs and ‘agentic AI’ tools is logarithmically more than that for search engines, which makes this a major challenge.

Issues like these is why services such as Cloudflare are offering blocking features for such automated traffic. After all, unless such traffic is of use to you, you may as well treat it like a DDoS attack and cut it off at the root.

Thanks to [Ben] for the tip.

Building A Fencing Scoring Box

July 25, 2026 by No comments

The sport of fencing requires keeping score, just like so many other similar pastimes. When their club’s existing scoring rig broke, [jc0025] stepped up to build a scoring box of their own, using the typical tools of the maker trade.

The brains of the operation is an Arduino Nano, running the venerable ATmega328P. It’s set up to drive a pair of 8×8 WS2812B addressable LED panels. It’s also hooked up to a pair of fencing socket blocks, which hook up to the lamé (jacket), weapon, and guard of each player for electronically scoring hits. The Arduino is thus programmed to respond to various conditions, lighting the LEDs in turn. For example, the tip of one player’s weapon hitting the other player’s lamé will fire a colored light, allowing the hit to be scored. Meanwhile, a tip hitting the floor will fire a white light, indicating off-target. There’s also a buzzer for sonic indication, as well. Everything is wrapped up in a tidy 3D-printed housing, while power is courtesy of a USB-C charger hooked up to the unit.

If you’re looking to replace some old broken fencing scoring gear on the cheap, this project is probably a good place to start. We’ve featured some other great scoreboard projects over the years, too. Meanwhile, if you’re whipping up your custom own gear for your local sporting club, we might like to hear about it on the tipsline.

An image of skyscrapers over a bay is shown, with some foliage along the bank. The sky and water are a pale blue-grey, while the foliage is pink.

Taking Tri-Camera True-Color Infrared Videos

July 25, 2026 by 14 Comments

Silicon-based CMOS camera sensors are cheap and plentiful, but they’re rarely used to their full potential: they can detect a greater range of wavelengths in the infrared spectrum than they can in the visible spectrum, but in most cameras this is blocked by an IR-cut filter. [Project 326]’s infrared camera system reverses this: it records infrared images in color while blocking out visible light.

The system uses three USB webcams, each with its IR cut filter removed and replaced with a different dichroic IR band-pass filter. One filter is centered at 750 nm, one at 850 nm, and one at 940 nm. There is no band overlap; in testing, each camera only detected an infrared flashlight tuned to its own filter wavelength. The original cameras didn’t hold the sensors in a consistent position, so [Project 326] designed new housings. Using three lenses, each with distinct aberrations, introduced some difficulties in alignment. [Project 326] originally intended to use a pair of beam-splitting prisms with only one lens, but this proved too difficult to align using 3D-printed frames.

A Raspberry Pi records a separate monochromatic stream from each camera, which can then be processed into a composite color video. The first frames need to be manually aligned, but afterwards a script can apply the alignment to the rest of the video. Finally, the channels are mapped to colors, with the precise mapping being freely changeable. There were some few unexpected issues: each camera has its own, not terribly precise, local oscillator, and they drifted apart by about one or two frames per minute. Parallax error, on the other hand, was less severe than might be expected: at close range it’s noticeable, but by a distance of 35 meters, it represents less than one pixel of distortion.

The resulting images look great, and it’s easy to forget that they’re being captured without the use of any visible light. We’ve seen a similar technique (though extending into the visible range) used to recreate the surreal effect of Aerochrome film.

A cardboard box (top left), set of instructions (top right), and a disassembled gaming console (bottom half) are strewn across a light blue tabletop, giving the impression that repair is impending.

Team Repair Breaks Things To Teach People How To Fix Them

July 25, 2026 by 7 Comments

Would you buy a broken device, fix it, then return the repaired item? [Team Repair] hopes you will.

Many people would rather repair what they have than have to get a new device and deal with all the annoyances of shopping and getting used to a new item. The problem is, most people don’t have any experience fixing their broken electronics and are intimidated by the process. [Team Repair] has found that helping people through the process the first time is a big confidence boost, especially when they have a test piece to work with.

[Team Repair] started with workshops and now has a “Fixers Club” subscription box for 8-14 year olds where they will send a broken device every three months to fix. After the device is repaired, it gets sent back into Team Repair, or iFixit in the US, to be broken again and sent to the next fixer. For grownups, there is a similar smartphone repair kit, but it’s currently waitlisted. If you’re in the UK, they even have a classroom program if you want to recruit larger groups into your fixer corps.

Curious about other ways to get into repairing your own things? We don’t recommend starting with smart rings, but learning analog repairs like zippers or turning a laptop into a desktop could be good places to start?

Continue reading “Team Repair Breaks Things To Teach People How To Fix Them” →

3D On The Playdate Handheld

July 25, 2026 by 13 Comments

The Playdate is a small handheld console with a dedicated fanbase. Among them is [Cristina Ramos], who recently decided to try and push the limits of the hardware by implementing a 3D renderer for the platform.

[Cristina] began by implementing a raycaster. This is a very simple way to do 3D on limited hardware, and this technique was used by some early games like Wolfenstein 3D. However, for [Cristina], it was more a test to get an idea of the performance limitations of the Playdate. After getting her feet wet with that, she stepped up to implementing a renderer that relied on binary space partitioning, which could load map files in the same format used by the classic Quake engine. There was naturally plenty of work to do to handle things like texture mapping and lighting, too, particularly given the vagaries of working with the Playdate’s 1-bit monochrome screen. Using a simplistic, cel-shaded like approach for textures gave things a good look while preserving visual readability on the low-resolution screen.

The 3D engine and associated game remain a work in progress for [Cristina] — we look forward to seeing where the project goes next. We’ve seen similar projects on resource-limited platforms before, too.

Continue reading “3D On The Playdate Handheld” →

Add Sensors To Everything!

July 25, 2026 by 23 Comments

“You can’t control what you can’t measure” goes the old chestnut. But that’s a little bit negative, in my opinion. Instead, think of the benefits of sprinkling sensors around everywhere: you gain insight where you simply didn’t have it beforehand.

We were thinking about this in the context of the recent video on pressure advance in 3D printers. Essentially, the unmelted filament acts as a springy piston, and that springiness means that the pressure built up in the melted plastic lags the feedrate of new filament. We usually calibrate this out with a guesstimate constant, but it can be different for every different filament. Measuring that pressure directly with a strain gauge in the hot end makes more sense.

But then there are knock-on benefits of having a sensor in the hot end. You can use the strain gauge as Prusa does to run the nozzle gently into the bed and set the z-axis height. Or you can use over-pressure as a sign that the nozzle is clogged. It’s quite possible that you can use it to signal other things that can go wrong as well, but you can’t tell until you put the sensor on in the first place.

Of course, you don’t want to put a pressure sensor where you want to know the temperature, or vice-versa. But as a general rule, the more you can measure, the more you can discover about the way your system is running. How many strain gauges are too many?

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