Useless Robot Gets Cute, Has Personality

Useless robots (or useless machines) are devices that, when switched on, exist only to turn themselves back off. They are fun and fairly simple builds that are easy to personify, and really invite customization by their creators. Even so, [tobychui]’s Kawaii Useless Robot goes above and beyond in that regard. Not only will his creation dutifully turn itself off, but if the user persists in engaging it, Kawaii Useless Robot grows progressively (and adorably) upset which ultimately culminates in scooting about and trying to run away.

If anything, it gets cuter when upset.

This is actually a ground-up re-imagining of an original work [tobychui] saw from a Japanese maker twelve years ago. That original Kawaii Useless Robot did not have any design details, so [tobychui] decided to re-create his own.

Behind the laser-cut front panel is a dot matrix LED display made up of eight smaller units, and inside are a total of four motors, an ESP32 development board, and supporting electronics. A neat touch is the ability to allow connections over Wi-Fi for debugging or remote control. The project page has some nice photos of the interior that are worth checking out. It’s a very compact and efficient build!

Watch it in action in the video (embedded below) which also includes a tour of the internals and a thorough description of the functions.

Inspired to make your own useless machine? Don’t be afraid to re-invent the whole concept. For example, we loved the one that physically spins the switch and the clock that falls to the floor when it detects someone looking at it. That last one is a close relative of the clock that displays the wrong time if and only if someone is looking.

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Cavity Filters, The Black Art You Have A Chance Of Pursuing

A tuned circuit formed by a capacitor and an inductor is a familiar enough circuit, and it’s understood that it will resonate at a particular frequency. As that frequency increases, so the size of the capacitor and inductor decrease, and there comes a point at which they can become the characteristic capacitance and inductance of a transmission line. These tuned circuits can be placed in an enclosure, at which they can be designed for an extremely high Q factor, a measure of quality, and thus a very narrow resonant point. They are frequently used as filters for that reason, and [Fesz] is here with a video explaining some of their operation and configurations.

Some of the mathematics behind RF design can be enough to faze any engineer, but he manages to steer a path away from that rabbit hole and explain cavity filters in a way that’s very accessible. We learn how to look at tuned circuits as transmission lines, and the properties of the various different coupling methods. Above all it reveals that making tuned cavities is within reach.

They’re a little rare these days, but there was a time when almost every TV set contained a set of these cavities which were ready-made for experimentation.

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Shapeways Files For Bankruptcy

One of the earliest hobbyist-friendly on-demand 3D printing and fabrication shops, Shapeways, is filing for bankruptcy. As these financial arrangements always go, this may or may not mean the end of the service, but it’s a sure sign that their business wasn’t running as well as you’d hope.

One of the standout features of Shapeways was always that they made metal printing affordable to the home gamer. Whether it was something frivolous like a custom gear-shifter knob, or something all-too functional like a prototype rocket engine, it was neat to have the alternative workflow of iterative design at home and then shipping out for manufacturing.

We don’t want to speculate too much, but we’d be surprised if the rise of similar services in China wasn’t part of the reason for the bankruptcy. The market landscape just isn’t what it was way back in 2013. (Sadly, the video linked in this article isn’t around any more. If anyone can find a copy, post up in the comments?) So while Shapeways may or may not be gone, it’s not like we can’t get metal parts made anymore.

Still, we’re spilling a little for the OG.

Thanks [Aaron Eiche] for the breaking news tip!

A small 3D-printed printing press with a print that says THE QUICK BROWN FOX JUMPED OVER THE LAZY BROWN DOG.

Mini 3D-Printed Press Is Sure To Make An Impression

Making stamps out of potatoes that have been cut in half is always a fun activity with the kids. But if you’ve got a 3D printer, you could really step up your printing game by building a mini relief printing press.

To create the gear bed/rack, [Kevr102] used a Fusion 360 add-in called GF Gear Generator. At first this was the most finicky part of the process, but then it was time to design the roller gears. However, [Kevr102] got through it with some clever thinking and a little bit of good, old-fashioned eyeballing.

Per [Kevr102], this press is aimed at the younger generation of printers in that the roller mechanism is spring-loaded to avoid pinched fingers. [Kevr102] 3D-printed some of the printing tablets, which is a cool idea. Unfortunately it doesn’t work that well for some styles of text, but most things came out looking great. You could always use a regular linocut linoleum tile, too.

This isn’t the first 3D-printed printing press to grace these pages. Here’s one that works like a giant rubber stamp.

A Cute Sentry Scans Your Net For Scullduggery

As long as we get to make our own network security tools, why not make them look cute? Netgotchi may not be much more than an ESP8266 running network scans and offering up a honeypot service, but it smiles while sits on your desk and we think that’s swell.

Taking inspiration from a recent series of red-team devices that make hacking adorable, most obviously pwnagotchi (and arguably Flipper), Netgotchi lives on the light side of the Force. Right now, it enumerates the devices on your network and can alert you when anything sketchy joins in. We can totally imagine customizing this to include other network security or health checks, and extending the available facial expressions accordingly.

You might not always be thinking about your network, and if you’re like us, that’s probably just fine. But we love standalone displays that show one thing in an easily digestable manner, and this fits the bill, with a smile.

Cloudflare Adds Block For AI Scrapers And Similar Bots

It’s no big secret that a lot of the internet traffic today consists out of automated requests, ranging from innocent bots like search engine indexers to data scraping bots for LLM and similar generative AI companies. With enough customers who are less than amused by this boost in useless traffic, Cloudflare has announced that it’s expanding its blocking feature for the latter category of scrapers. Initially this block was only for ‘poorly behaving’ scrapers, but now it apparently targets all of such bots.

The block seems to be based around a range of characteristics, including the user agent string. According to Cloudflare’s data on its network, over 40% of identified AI bots came from ByteDance (Bytespider), followed by GPTBot at over 35% and ClaudeBot with 11% and a whole gaggle of smaller bots. Assuming that Imperva’s claims of bots taking up over half of today’s internet traffic are somewhat correct, that means that even if these bots follow robots.txt, that is still a lot of bandwidth being drained and the website owner effectively subsidizing the training of some company’s models. Unsurprisingly, Cloudflare notes that many website owners have already taken measures to block these bots in some fashion.

Naturally, not all of these scraper bots are well-behaved. Spoofing the user agent is an obvious way to dodge blocks, but scraper bot activity has many tell-tale signs which Cloudflare uses, as well as statistical data across its global network to compute a ‘bot score‘ for any requests. Although it remains to be seen whether false positives become an issue with Cloudflare’s approach, it’s definitely a sign of the times that more and more website owners are choosing to choke off unwanted, AI-related traffic.

A Second OctoPrint Plugin Has Been Falsifying Stats

The ongoing story of bogus analytical data being submitted to the public OctoPrint usage statistics has taken a surprising turn with the news that a second plugin was being artificially pushed up the charts. At least this time, the developer of the plugin has admitted to doing the deed personally.

Just to recap, last week OctoPrint creator [Gina Häußge] found that somebody had been generating fictitious OctoPrint usage stats since 2022 in an effort to make the OctoEverywhere plugin appear to be more popular than it actually was. It was a clever attempt, and if it wasn’t for the fact that the fake data was reporting itself to be from a significantly out of date build of OctoPrint, there’s no telling how long it would have continued. When the developers of the plugin were confronted, they claimed it was an overzealous user operating under their own initiative, and denied any knowledge that the stats were being manipulated in their favor.

Presumably it was around this time that Obico creator [Kenneth Jiang] started sweating bullets. It turns out he’d been doing the same thing, for just about as long. When [Gina] contacted him about the suspicious data she was seeing regarding his plugin, he owned up to falsifying the data and published what strikes us as a fairly contrite apology on the Obico blog. While this doesn’t absolve him of making a very poor decision, we respect that he didn’t try to shift the blame elsewhere.

That said, there’s at least one part of his version of events that doesn’t quite pass the sniff test for us. According to [Kenneth], he first wrote the script that generated the fake data back in 2022 because he suspected (correctly, it turns out) that the developers of OctoEverywhere were doing something similar. But after that, he says he didn’t realize the script was still running until [Gina] confronted him about it.

Now admittedly, we’re not professional programmers here at Hackaday. But we’ve written enough code to be suspicious when somebody claims a script they whipped up on a lark was able to run unattended for two years and never once crashed or otherwise bailed out. We won’t even begin to speculate where said script could have been running since 2022 without anyone noticing…

But we won’t dwell on the minutiae here. [Gina] has once again purged the garbage data from the OctoPrint stats, and hopefully things are finally starting to reflect reality. We know she was already angry about the earlier attempts to manipulate the stats, so she’s got to be seething right about now. But as we said before, these unfortunate incidents are ultimately just bumps in the road. We don’t need any stat tracker to know that the community as a whole greatly appreciates the incredible work she’s put into OctoPrint.