Adding a Riving Knife for Table Saw Safety

What in the world is a riving knife? Just the one thing that might save you from a very bad day in the shop. But if your table saw doesn’t come with one, fret not — with a little wherewithal you can add a riving knife to almost any table saw.

For those who have never experienced kickback on a table saw, we can assure you that at a minimum it will set your heart pounding. At the worst, it will suck your hand into the spinning blade and send your fingers flying, or perhaps embed a piece of wood in your chest or forehead. Riving knives mitigate such catastrophes by preventing the stock from touching the blade as it rotates up out of the table. Contractor table saws like [Craft Andu]’s little Makita are often stripped of such niceties, so he set about adding one. The essential features of a proper riving knife are being the same width as the blade, wrapping closely around it, raising and lowering with the blade, and not extending past the top of the blade. [Craft Andu] hit all those points with his DIY knife, and the result is extra safety with no inconvenience.

It only takes a few milliseconds to suffer a life-altering injury, so be safe out there. Even if you’re building your own table saw, you owe it to yourself.

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Ask Hackaday: SawStop — Bastion of Safety or Patent Troll

At first glance, SawStop seems like a hacker’s dream. A garage tinkerer comes up with a great idea, builds a product around it, and the world becomes a better place. As time has gone on, other companies have introduced similar products. Recently, SawStop successfully stopped Bosch from importing saws equipped with their Reaxx safety system into the USA. This not only impacts sales of new saws, but parts for existing equipment. Who gets screwed here? Unfortunately, it’s the owners of the Bosch saws, who now have a safety feature they might not be able to use in the future. This has earned some bad press for SawStop in forums and on websites like Reddit, where users have gone as far as to call SawStop a patent troll. Is that true or just Internet puffery? Read on and decide for yourself.

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Hackaday Prize Entry: Safety Glasses Are Also Hands-Free Multimeter

It seems like the multimeter is never easy to see during a project. Whether it’s troubleshooting a vehicle’s electrical system and awkwardly balancing the meter on some vacuum lines and the intake manifold, or installing a new solar panel and hoping the meter doesn’t fall on the ground while the leads are in both hands, it seems like there’s never a good way to see the meter while actually using it. Some meters have a small magnet and strap that can be used to hang them temporarily, but this will only get you so far.

[Alain Mauer]’s entry into the Hackaday Prize looks to solve this glaring problem. Using a heads-up Bluetooth display mounted to a pair of safety glasses, a multimeter can be connected to the device in order to display its information directly to its user. Based on his original idea which used a normal pair of prescription glasses as its foundation, [Alain]’s goal is to reduce safety hazards that might arise when using a multimeter in an awkward or dangerous manner that might not otherwise be possible.

The device uses an Arduino Pro Micro to connect to the multimeter and drive the display. [Alain] notes that the real challenge is with the optical system, however. Either way though, this would be a welcome addition to any lab, workspace, or electrician’s toolbox. Be sure to check out the video of it in action after the break.

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Exoskeleton Aims to Prevent Falls for Seniors

When we think of exoskeletons, we tend to think along comic book lines: mechanical suits bestowing superhero strength upon the villain. But perhaps more practical uses for exoskeletons exists: restoring the ability to walk, for instance, or as in the case of these exoskeleton shorts, preventing hip fractures by detecting and correcting falls before they happen.

Falls and the debilitating injuries that can result are a cruel fact of life for the elderly, and anything that can potentially mitigate them could be a huge boon to public health. Falls often boil down to loss of balance from slipping, whether it be a loose rug, a patch of ice, or even the proverbial banana peel. The “Active Pelvic Orthosis” developed by [Vito Monaco] and colleagues seeks to sense slips and correct them by applying the correct torque to the hip joints. Looking a little bulky in their prototype form and still tethered to an external computer, the shorts have motors with harmonic drives and angle sensors for each hip, plus accelerometers to detect the kinematic signature of a slip. The researchers discovered that forcing the leg that slipped forward while driving the stable leg back helped reduce the possibility of a fall. The video below shows the shorts in action preventing falls on a slip-inducing treadmill.

At the Hackaday Unconference in Pasadena, we heard from [Raul Ocampo] on his idea for autonomous robots to catch falling seniors. Perhaps wearing the robot will end up being a better idea.

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We’ve Got It Down PAT: Appliance Electrical Safety Testing

Everywhere we look in our everyday lives, from our bench to our bedroom, there are the ubiquitous electrical cords of mains-powered appliances. We don’t give our electrical devices a second thought, but in addition to their primary purpose they all perform the function of keeping us safe from the dangerous mains voltages delivered from our wall sockets.

Of course, we’ve all had appliances that have become damaged. How often have you seen a plug held together with electrical tape, or a cord with some of its outer sheath missing? It’s something that we shouldn’t do, but it’s likely many readers are guiltily shuffling a particular piece of equipment out of the way at the moment.

In most countries there are electrical regulations which impose some level of electrical safety on commercial premises. Under those regulations, all appliances must be regularly tested, and any appliances that fail the tests must be either repaired or taken out of service

In the United Kingdom,where this piece is being written, the law in question is the Electricity At Work Regulations 1989, which specifies the maintenance of electrical safety and that there should be evidence of regular maintenance of electrical appliances. It doesn’t specify how this should be done, but the way this is usually achieved is by a set of electrical tests whose official name: “In-service Inspection & Testing of Electrical Equipment”, isn’t very catchy. Thus “Portable Appliance Testing”, or PAT, is how the process is usually referred to. Join me after the break for an overview of the PAT system.

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Don’t Try This at Home is Cliché for a Reason

Oh, for cryin’ out loud. That’s the last straw. We’ve seen one dangerous YouTube video too many. Are we honestly cursed with a false feedback system that unequitably rewards dangerous behavior in online videos? Obviously the answer is ‘yes’. Now the real question becomes, can we do anything about it?

Professional Driver on a Closed Course

Marketing is all about putting something in front of a consumer and getting their brain to go “awesome!”. The fast, loud, shiny, burny, and sharp things are all on the table for that task. It’s the primal part of your brain that gives you jolt, as if your amygdala forgot how to run from sabertooths (saberteeth?) and learned how to like and subscribe.

Back in the day, people were hurt and even killed when replicating stunts they saw done on television. To protect from litigation, companies started adding disclaimers — Don’t Try this at Home or my favorite: Professional Driver on a Closed Course.

But the thing is, commercials are big business. If someone gets hurt, there’s money to be had by assigning blame in a court of law. When the ability to produce and distribute video content was democratized by the coming of the Internet we lost those warnings and the common sense that went with them.

Going way back to this remote-control-a-real-car hack in 2009 I haven’t been able to shake the lack of consideration for danger in a project like this. I included it in the title, which ends with “(dangerously)”. While I wasn’t taken to task in the comments for that title, I have been chided for advocating for things as controversial as helmets when strapping your body to a moving object. Do a Ctrl-F on “helmet” in this article to see what I mean.

The people pulling off these hacks were doing it because it felt awesome and they wanted to document how that felt. They weren’t stars, they were hackers and the world mostly ignored them except in places like Hackaday. We might debate the lack of safety measures but most assumed anyone with skills to do this would take a beat to consider the risks. This was probably a false assumption.

It’s All About the Subs

Things have gotten worse since then. I can’t blame all of this on YouTube, but I’m going to try. One day, YouTube changed everything. They put together a perfect mix of easy uploading, great discoverability, and (most importantly) advertising revenue sharing. For some people, this became a business and not just a way to connect with the rest of the hacker community.

This is the rise of the subscriber base. It’s a vicious cycle — you need more people to like and subscribe so that their influence will push your channel to more people to like and subscribe. The problem is, the fastest way to this is that tricky amygdala again. For some, this is being funny, but for others this is speed, fireballs, and loud bangs, with no regard for life, limb, or eyeball.

We’re Far From Blameless

I like fireballs and fast cars as much as the next person. And we’ve certainly run a lot of articles on the escalatingly dangerous hacks out there for all to see. For instance, we’ve covered several hacks from [kreosan], like microwaving things outside of a microwave and then building a microwave gun.

Pyro Build
Short sleeves and flamethrowers. What could go wrong?

But even the more mainstream content appears to be getting more and more dangerous. Our beloved [Colin Furze] is guilty of dangerous behavior. Not only did he burn himself testing a jet engine out without any safety gear, but turned the aftermath into another ad-supported video.

Which brings me to the straw that broke the camel’s back. Here’s a hack that’s based on the idea of hurting people. It’s what is (luckily) a crappy robot designed to recognize faces and shine lasers into any eyes it detects. Literally it’s conceived to shoot your eyes out. It’s using a red laser that likely won’t cause eye damage unless you intentionally stare into it without blinking, but that’s not discussed in the video, and someone who doesn’t know better replicating this with a different laser could easily cause irreparable damage to their sight.

Rocket Scientists Use Common Sense and So Should You

I was going to use the heading “This Isn’t Rocket Science”, but you don’t see rocket scientists testing new engine designs by lighting a fuse as they run away giggling in short sleeves and flip-flops. Those brilliantly intelligent people are tucked safely in a bunker at a safe distance with their hands hovering over the emergency kill switch as fire fighting equipment hangs out at arms reach. Rocket scientists know a lot about safety and so should you.

This is simple. We don’t have to invent anything to add safety to our hacks. Use common sense. Dress appropriately for your demo — as the situation dictates use reasonable fire-resistant clothing, helmet, etc. Wear protective glasses, laser spec’d goggles, and ear plugs; each whenever called for. Take fumes and particulates seriously and wear respiratory gear. Keep a fire extinguisher around. And if you’re making a video or posting images about it — which you should definitely do — snap a picture or give us a quick video cut to the safety precautions you’ve chosen.

I still want to see awesome projects on YouTube. But I also want to see the trend towards danger for clicks stopped. Let’s do dangerous stuff safely. And let’s be conspicuous about those safety measures. That combination is truly awesome.

Now get off my lawn, and wear your seat belt while doing so.

The Shocking Truth About Transformerless Power Supplies

Transformerless power supplies are showing up a lot here on Hackaday, especially in inexpensive products where the cost of a transformer would add significantly to the BOM. But transformerless power supplies are a double-edged sword. That title? Not clickbait. Poking around in a transformerless-powered device can turn your oscilloscope into a smoking pile or get you electrocuted if you don’t understand them and take proper safety precautions.

But this isn’t a scare piece. Transformerless designs are great in their proper place, and you’re probably going to encounter one someday because they’re in everything from LED lightbulbs to IoT WiFi switches. We’re going to look at how they work, and how to design and work on them safely, because you never know when you might want to hack on one.

Here’s the punchline: transformerless power supplies are safely useable only in situations where the entire device can be enclosed and nobody can accidentally come in contact with any part of it. That means no physical electrical connections in or out — RF and IR are fair game. And when you work with one, you have to know that any part of the circuit can be at mains voltage. Now read on to see why!

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