Retired Welding Robot Picks Up Side Hustle As CNC Router

April 11, 2023 by 19 Comments

Who says you can’t teach an old robot new tricks? Nobody, actually. That saying is about dogs. But it applies to robots too, at least judging by the way this late-90s industrial beast was put to use in a way it was never intended: as a giant CNC router.

The machine in question is an ABB IRB6400, a six-axis, floor-mounted industrial machine that had a long career welding at a Eurorail factory in Austria before [Brian Brocken] made its acquaintance. He procured the non-working machine — no word on what he paid for it — and moved the 2-ton paperweight into his shop, itself a non-trivial endeavor. After a good scrubbing, [Brian] tried to get the machine started up. An error prevented the robot controller from booting; luckily, there’s a large community of ABB users, and [Brian] learned that one of the modules in the controller needed replacement.

After fixing that — and swapping out the controller’s long-dead backup batteries, plus replacing the original 1.44 MB floppy drive with a USB drive — he was able to bring the machine back to life. Unfortunately, the limited amount of internal memory made it difficult to use for anything complicated, so [Brian] came up with an application to stream coordinates to the controller over a serial port, allowing for unlimited operation. With that in place, plus a simple spindle mounted to the robot’s wrist with a 3D printed adapter, [Brian] was able to carve foam blocks into complex shapes. The video below shows everything from delivery to first chips — well, dust at least.

This build seems to be a significant escalation from [Brian]’s previous large-format CNC machine. He must have something interesting in mind, so stay tuned for details.

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Your Multimeter Might Be Lying To You

April 10, 2023 by 33 Comments

Multimeters are indispensable tools when working on electronics. It’s almost impossible to build any but the most basic of circuits without one to test and troubleshoot potential issues, and they make possible a large array of measurement capabilities that are not easily performed otherwise. But when things start getting a little more complex it’s important to know their limitations, specifically around what they will tell you about circuits designed for high frequency. [watersstanton] explains in this video while troubleshooting an antenna circuit for ham radio.

The issue that often confuses people new to radio or other high-frequency projects revolves around the continuity testing function found on most multimeters. While useful for testing wiring and making sure connections are solid, they typically only test using DC. When applying AC to the same circuits, inductors start to offer higher impedance and capacitors lower impedance, up to the point that they become open and short circuits respectively. The same happens to transformers, but can also most antennas which often look like short circuits to ground at DC but can offer just enough impedance at their designed frequency to efficiently resonate and send out radio waves.

This can give some confusing readings, such as when testing to make sure that a RF connector isn’t shorted out after soldering it to a coaxial cable for example. If an antenna is connected to the other side, it’s possible a meter will show a short at DC which might indicate a flaw in the soldering of the connector if the user isn’t mindful of this high-frequency impedance. We actually featured a unique antenna design recently that’s built entirely on a PCB that would show this DC short but behaves surprisingly well when sending out WiFi signals.

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The Hello World Of GPT?

April 10, 2023 by 73 Comments

Someone wants to learn about Arduino programming. Do you suggest they blink an LED first? Or should they go straight for a 3D laser scanner with galvos, a time-of-flight sensor, and multiple networking options? Most of us need to start with the blinking light and move forward from there. So what if you want to learn about the latest wave of GPT — generative pre-trained transformer — programs? Do you start with a language model that looks at thousands of possible tokens in large contexts? Or should you start with something simple? We think you should start simple, and [Andrej Karpathy] agrees. He has a workbook that makes a tiny GPT that can predict the next bit in a sequence. It isn’t any more practical than a blinking LED, but it is a manageable place to start.

The simple example starts with a vocabulary of two. In other words, characters are 1 or 0. It also uses a context size of 3, so it will look at 3 bits and use that to infer the 4th bit. To further simplify things, the examples assume you will always get a fixed-size sequence of tokens, in this case, eight tokens. Then it builds a little from there.

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My Glasses Hear Everything I’m Not Saying!

April 10, 2023 by 4 Comments

There was a time when you saw someone walking down the street talking to no one, they were probably crazy. Now you have to look for a Bluetooth headset. But soon they may just be quietly talking to their glasses. Cornell University researchers have EchoSpeech which use sonar-like sensors in a pair of glasses to watch your lips and mouth move. From that data, they can figure out what you are saying, even if you don’t really say it out loud. You can see a video of the glasses below.

There are a few advantages to a method like this. For one thing, you can speak commands even in places where you can’t talk out loud to a microphone. There have been HAL 9000-like attempts to read lips with cameras, but this is power-hungry and video tends to be data intensive.

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Busting Wireless ESD Wrist Straps With LTT And ElectroBOOM

April 10, 2023 by 28 Comments

Nobody likes getting zapped from an electrostatic discharge, no matter whether you’re a fragile ASIC or a bag-of-mostly-salty-water humanoid. To prevent this, ESD wrist straps and similar are essential tools, as they prevent the build-up of a charge on your humanoid’s skin, essentially like a very large electrolyte-filled capacitor. Yet you can buy wireless ESD straps everywhere that are supposed to somehow dissipate this charge into the ether, even though this would seem to undermine the laws of physics that make capacitors work.

In a practical experimentation and assorted hijinks video collaboration by [Linus] from Linus Tech Tips and [Mehdi Sadaghdar] from ElectroBOOM put these wireless ESD straps to the test, featuring [Mehdi]’s DIY Van de Graaff generator to charge [Linus] up. What is excellently demonstrated in this video is how effective a real ESD strap is, and how the ‘wireless’ version is just a scam that does absolutely nothing to dissipate the charge, being just a waste of a 1 MOhm resistor and what could have been a real ESD strap.

Also covered in the video are what the reason for the resistor in an ESD strap is, and why metal bracelet type ESD straps are not appropriate, for very good reasons.

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Dyson Hair Dryer Becomes Jet Engine

April 10, 2023 by 18 Comments

While Dyson makes some good products, they aren’t known for being economical. Case in point: [Integza] spent $500 on a hair dryer. While he does have a fine head of hair, we suspected he wasn’t after it for its intended purpose, and we were right. It turns out he wanted to make it into a jet engine! Why? Oh, come on. The fact that you read Hackaday means you don’t need that question answered. Watch the video below to see how it all turned out.

What got [Integza]’s attention was the power of the very small motor. So he immediately, of course, opened it up. The build quality is very impressive, although for $500, shouldn’t it be? While we are sure the Dyson dryer is more robust than our $9 Revlon special, it seems doubtful that it would handle the high temperatures of a jet exhaust. In fact, he’s had plastic meltdown while trying to build a jet before. So this time, he had a different plan.

That plan involved designing a replacement shell for the dryer and having it 3D printed in metal, which may have cost almost as much or more than the dryer. It came out great, though — and some fuel lines and a spark plug later, he was ready to fire it up.

Did it work? You bet. Test equipment was melted accidentally, and eventually, the engine looked like it flamed out. But it generated some very hot exhaust. We’d like to say that no tomatoes were harmed during the production of the video, but we can’t because of our well-developed sense of ethics. Poor tomatoes! We might have used a Mr. Bill doll, but that probably infringes on someone’s copyright.

If you don’t want so much melting, maybe try water cooling. If you could make this reliable, the modification to your car becomes obvious.

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Supercon 2022: Aedan Cullen Is Creating An AR System To Beat The Big Boys

April 10, 2023 by 10 Comments

There’s something very tantalizing about an augmented reality (AR) overlay that can provide information in daily life without having to glance at a smartphone display, even if it’s just for that sci-fi vibe. Creating a system that is both practical and useful is however far from easy, which is where Aedan Cullen‘s attempt at creating what he terms a ‘practical augmented reality device’.

In terms of requirements, this device would need to have a visual resolution comparable to that of a smartphone (50 pixels/degree) and with a comparable field of view (20 degrees diagonal). User input would need to be as versatile as a touchscreen, but ‘faster’, along with a battery life of at least 8 hours, and all of this in a package weighing less than 50 grams.

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