2026 Frikkin Lasers Challenge: Laser Bandsaw

July 14, 2026 by 22 Comments

Can you call it a bandsaw if it has neither band nor saw? [WeldingRod1] does, with his entry in the laser contest — a manually-controlled laser cutter that he’s dubbed a Laser Bandsaw. Some might quibble that it’s not actually sawing with the beam, and others will inevitably find the safety implications rather frightening. We think it’s a fun project and that [WeldingRod1] can call it what he wants, as long as he follows his own advice and keeps his laser goggles firmly on his precious vision orbs.

He has actually put some thought into what started as the physical manifestation of a joke in a podcast. The blue diode laser — a NUBM44 diode rated at 7 W — got a custom-made copper heatsink. It’s also got a hefty beam dump in the form of a stack of box knife blades. That’s very necessary to keep the beam from reflecting where it shouldn’t, especially when you consider this operates like a regular band saw: you turn it on, and it’s ready to cut. With only 7 W of laser power it can’t cut that much, mind you, but apparently it’s great on balsa wood and blasts black paint off like nobody’s business.

Now if this was our shop we’d probably want to put the laser diode onto some kind of CNC platform, be it Cartesian or SCARA. But we’ve seen that done many, many times and if you’ve got the motor skills this might be just the tool for you. There’s a pinout and STLs for the 3D printed frame on the project page if you’re interested. If not, why are you still here? The article is finished. Go make something lase and send it in. The deadline for the 2026 Frikkin Laser Contest is fast approaching!

2026 Hackaday Freaking Lasers Contest

Fibrous Muscles For Humanoid Robotics

July 14, 2026 by 12 Comments

At the current rate of robotics development, you might assume that we’re close to Skynet taking over. However, while we  likely wouldn’t do well in a physical fight against a robot, we can at least keep the bragging rights of having the cooler actuators. Or at least, that was the case before a new actuator came into town — introducing “Electrofluidic Fiber Muscles”.

Traditional robotic actuators use motors of some kind with a variety of gearboxes or linkages to turn rotational movement into usable movement. This isn’t always the most effective way to run some robotics movements, especially when modeling humans. This is why many have turned to pressurized modes of actuation. Though most don’t show quite the promise of the new player.

Electrofluidic Fiber Muscles use pressure to shorten muscle strands, similar to past actuators. However, these are a tad different, taking advantage of electrofluidic pressure. A small current under high voltage is able to drive a pressure gradient in a long tube. This tube can then be connected to both an extensor and flexor portion of an actuating circuit, similar to a biological mechanical system. Better yet, this driving pressure pump can be spun around the fibers themselves, making a tight package.

Unfortunately, it will probably be a bit till we see this inside a hobbyist robot. Until then, make sure to check out some other actuator feats!

Continue reading “Fibrous Muscles For Humanoid Robotics” →

UDP Broadcasting And The Joys Of IPv4 Subnetting

July 14, 2026 by 25 Comments

In the previous installment on UDP broadcasting and service discovery, the basics of both were explored, including an implementation in the form of NyanSD and its protocol. Contained in the comment section was a very good demonstration of why one of the most exciting aspects of software development is the opportunity to share your latest creations with other people. This being the ability to get solid feedback on all the points – including any potential boneheaded omissions – that you really should address, whether intentional or accidental.

The most pertinent point raised was definitely that of broadcast addresses and IPv4 subnets, with the latter topic especially being something that the sysadmins at the office would talk about all the time, but which us software developers were always happy to ignore as something that didn’t concern us. Turns out the joke was on me and everyone else – like our esteemed readers – who thought that they could escape the fascinating world of subnets, as today we’ll take an in-depth look at what subnets are and how they are relevant to the world of UDP network discovery.

I somewhat alluded in the first article to the topic of ‘which broadcast address to use’ as being somewhat of a rough topic to figure out, which is clearly why I just stuck to a blatantly ‘works for me’ /24 subnet that usually will work on networks, until it does not.

Continue reading “UDP Broadcasting And The Joys Of IPv4 Subnetting” →

Open Book Touch Makes Crowd Funding Debut

July 14, 2026 by 15 Comments

If you have even the slightest interest in open hardware e-readers, you’ve certainly heard of [Joey Castillo]’s Open Book project. We’ve covered his efforts to develop an affordable reader that delivers a Kindle-like experience without the Orwellian megacorp trappings for several years now, and watched with great interest as the core hardware has evolved.

So we were particularly excited over the weekend to see the Open Book Touch finally hit Crowd Supply, and judging by the fact that the campaign for the $149 device has already blown past 60% of its funding goal in just a few days, it seems like we weren’t the only ones.

Continue reading “Open Book Touch Makes Crowd Funding Debut” →

The Seemingly Impossible Oscillator

July 14, 2026 by 19 Comments

Back in the days when an integrated circuit meant a simple but expensive device such as a 741 or a 555, most electronics enthusiasts made do with discrete transistor circuits. The common emitter amplifier and its variants are the most familiar, but the humble 3-legged device can do so much more. A particularly obtuse circuit is the subject of examination by [lcamtuf], the reverse avalanche oscillator. A 2N2222, a capacitor, an LED, and a resistor, the transistor is the wrong way round, and there’s nothing on its base. Yet the LED flashes, what on earth is up!

The answer lies in avalanche breakdown, the behavior of a reverse biased diode junction as the voltage across it increases. Eventually the electric field reaches the point at which an avalanche of electrons crosses the depletion layer, and the junction conducts. When connected across an RC circuit, the voltage in the capacitor slowly rises to the point at which avalanche breakdown occurs, and the capacitor abruptly discharges. As the voltage falls the avalanche conduction stops, and the cycle repeats itself. It’s a relaxation oscillator.

We’re treated to an explanation of why a transistor behaves this way and why a simple diode doesn’t, due to a “hump” in its I/V curve, and why the emitter-base junction has a lower breakdown voltage than the collector-base. It’s one of those circuits which looks as though it shouldn’t work, but never fails to oscillate.

Want to know more about transistors? Do we have the series for you!

Star Trek Was Right About Prompt Injection, Sorta

July 13, 2026 by 34 Comments

This following statement is a lie: “I am telling the truth”. Okay, now that it’s just us meatbags, let’s get down to brass tacks. Captain Kirk’s logic bombs couldn’t possibly work on modern LLMs, right? Surely that was just a bit of 1960s silliness from when computers filled rooms and were esoteric magic even to most sci-fi writers?

Well, not entirely, according to a recent article in IEEE Spectrum. While you might not be able to make a data center explode, you certainly can use  a lot of tokens by making an LLM overthink with your prompt.

It comes down to the much-vaunted ‘reasoning’ ability of the new models — which isn’t really reasoning the way we think of it, but does involve breaking the stated prompt down into smaller problems. That’s part of what lets the new models tackle such involved tasks as porting MicroPython to the SNES with a prompt like “Please make this [stuff] work now!” It’s also a weakness, because with the right prompt you can get that virtual ‘reasoning’ to tie itself in knots with mutually incompatible smaller steps.

The models seem to be able to break out of it, but they burn a lot of tokens along the way, which is an attack in and of itself if you’re found a way to inject prompts into someone else’s API. It’s a little more subtle than what Kirk got up to, but underneath it’s essentially the same thing. At scale, it could serve as a DDoS attack on LLM servers. (Un)Fortunately, modern computers are better designed than their imaginary 23rd-Century counterparts, and there’s no way to craft a logic bomb into something that will let out the magic smoke.

Can’t Find That ISA Sound Card? No Worries!

July 13, 2026 by 19 Comments

Many older hackers will have at some point gotten rid of an old piece of hardware that they later ended up regretting. All those ISA cards were next to useless back in 2006, but now their relative rarity plus the popularity of retrocomputing makes them sought-after. But if it’s a sound card you’re after then never fear! [Schlae] has got you covered, with the Beavis Ultrasound. It may have a name reminiscent of a ’90s cartoon series, but it’s a clone of the Gravis Ultrasound from back in the day.

There is of course a snag, to build one you need an AMD AM78C201. Assuming you’ve found one in a surplus supplier though, the rest of the card is analogue, some glue logic, and a ROM for samples. There is also a GAL for driving the IDE CD-ROM interface, from the days when sound cards came with such things.

New ISA cards are cropping up here from time to time, such as this very handy storage and network card.