When Battery Rebuilds Go Wrong: Understanding BMSs, Spot Welders, And Safety

February 16, 2022 by Ryan Flowers 41 Comments

Batteries are amazing. Batteries are horrible. Batteries are a necessary evil in today’s world of portable everything. If you’re reading this sentence, even if it’s not on a mobile device, somewhere there is a battery involved. They’re that ubiquitous. There’s another thing batteries are: Expensive! And at $350 each for a specialized battery, [Linus] of Linus Tech Tips decided to take battery repair into his own hands.

Rather than do a quick how-to video about putting new cells in an old enclosure, [Linus] does a deep dive into the equipment, skills, and safety measures needed when dealing with Lithium Ion cells. And if you watch the video through, you’ll even get to see those safety measures put to good use!

The real meat of the video comes toward the end however, with its explanation of the different Battery Management Systems (BMS), and a discussion of the difficulty of doing battery repair correctly and safely. Lastly, the video covers something a bit more sinister: Batteries that are made to resist being repaired with new cells; DRM for batteries, so to speak.

Overall we found the video informative, and we hope you do too. You might also enjoy this peek into the chemistry behind your favorite battery types.

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Martian Wheel Control Algorithms Gain Traction

February 15, 2022 by Ryan Flowers 13 Comments

Imagine the scene: You’re puttering along in your vehicle when, at least an hour from the nearest help, one of your tires starts losing air. Not to worry! You’ve got a spare tire along with the tools and knowhow to change it. And if that fails, you can call roadside assistance. But what if your car isn’t a car, has metal wheels for which no spares are available, and the nearest help is 200 million miles away? You just might be a Jet Propulsion Laboratory Engineer on the Curiosity Mars Rover mission, who in 2017 was charged with creating a new driving algorithm designed to extend the life of the wheels.

High Performance Rock Crawler, Courtesy Spidertrax.com License: CC BY 3.0

You could say that the Curiosity Mars rover is the ultimate off-road vehicle, and as such it has to deal with conditions that are in some ways not that different from some locations here on Earth. Earth bound rock crawlers use long travel suspensions, specialized drivetrains, and locking differentials to keep the tires on the ground and prevent a loss of traction.

On Mars, sand and rocks dominate the landscape, and a rover must navigate around the worst of it. It’s inevitable that, just like a terrestrial off-roader, the Mars rovers will spin a tire now and then when a wheel loses traction. The Mars rovers also have a specialized drivetrain and long travel suspensions. They don’t employ differentials, though, so how are they to prevent a loss of traction and the damaging wheel spin that ensues? This where the aforementioned traction control algorithm comes in.

By controlling the rotation of the wheels with less traction, they can still contribute to the motion of the vehicle while avoiding rock rash. Be sure to check out the excellent article at JPL’s website for a full explanation of their methodology and the added benefits of uploading new traction control algorithms from 200 million miles away! No doubt the Perseverance Mars rover has also benefited from this research.

But why should NASA get to have all the fun? You can join them by 3d printing your own Mars rover and just maybe some Power Wheels derived traction control. What fun!

Camping For $25: Thrift Store Hacks To Keep Cozy

February 5, 2022 by Ryan Flowers 18 Comments

A hacker is somebody who’s always thinking creatively to solve problems, usually using what they have on hand. Sometimes that means using a 555 to build a CPU, and other times it means using a dead flashlight to start a fire. In the video below the break, [Kelly] shows us a series of hacks you can use while camping in the woods for a night to keep you warm, dry, and well fed!

[Kelly] started his camping trip not in the woods, but rather at a local thrift store. Instead of packing along hundreds of dollars in gear, his aim was to keep costs low. Very low. With some searching he was able to find a blanket, cooking utensils, rope, knife, tarp, and several other camp necessities for just $25.

A good campfire is a necessity of course, and [Kelly]’s full of great ways to start a fire even if all you have is a lighter with no butane or an old flashlight with dead batteries. The purpose of the video is to show how anyone can get their bush craft on even when all they have is a few dollars and a little know-how, which he generously shares. And after watching, we’re sure you’ll agree that he met his mark.

Will you raid the local second hand store before your next camping trip? After seeing this video, you just might! And while you’re there, make sure to grab the things you’ll need to make your own camping-friendly French press so you have some good coffee while you’re out camping in your… uh… Corolla?

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Retrotechtacular: Understanding The Strength Of Structural Shapes

February 3, 2022 by Ryan Flowers 13 Comments

Strength. Rigidity. Dependability. The ability to bear weight without buckling. These are all things that we look for when we build a mechanical structure. And in today’s Retrotechtacular we take a closer look at the answer to a question: “What’s in A Shape?”

As it turns out, quite a lot. In a wonderful film by the prolific Jam Handy Organization in the 1940’s, we take a scientific look at how shape affects the load bearing capacity of a beam. A single sided piece of metal, angle iron, C-channel, and boxed tubing all made of the same thickness metal are compared to see not just just how much load they can take, but also how they fail.

The concepts are then given practical application in things that we still deal with on a daily basis: Bridges, cars, aircraft, and buildings. Aircraft spars, bridge beams, car frames, and building girders all benefit from the engineering discussed in this time capsule of film.

None of the concepts in this video are suddenly out of date, because while our understanding of engineering has certainly progressed since this film was made, these basic concepts remain the same. As such, they will apply to any structural or mechanical devices that we make, be it 3d printed, CNC routed, welded, glued, vacuum formed, zip tied, duct taped, bailing wired, or hot glued.

Keep your eyes open for a wonderful sights and sounds of a rare Boeing 314 Clipper landing on water and a 1920’s Buffalo Springfield Steam Roller demonstrating how wonderful the film’s sponsor, Chevrolet, makes their automobile frames.

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Arduino Activated Automotive Aerodynamic Apparatus Is… (Spoiler Alert!)

February 3, 2022 by Ryan Flowers 8 Comments

Sometimes a great hack is great for no other reason than that it’s fun, and [Michael Rechtin]’s DIY Active Aero Spoiler and Air Brake certainly qualifies as a fun hack. This is a mod designed to live in a world where looks are everything, stickers add horsepower, and a good sound system is more important than good wheel alignment. Why is that? Because like the switch that exists only to activate the mechanism that turns it off, the DIY Active Aero Spoiler and Air Brake seen below is almost completely useless. So to understand its allure, we must understand its inspiration.

For a few decades now, luxury sports car manufacturers have been adding active aerodynamic components to their vehicles. For example, several Porsche models feature adaptive spoilers that adjust to driving conditions. Super cars such as the Bugatti Veyron have spoilers that flip up at high angles during braking to increase drag and reduce braking distance. All of these features are sadly missing from the average two or four door family-car-turned-wannabe-track-fiend. Until now!

[Michael] has created a new active spoiler for every mall-bound muffler-challenged hand me down. The build starts with a CNC cut foam wing which is covered with fiberglass, Bondo (an automotive necessity) and some faux carbon fiber for that go-fast feel. An Arduino, IMU, two servos, and a battery pack detect deceleration and automatically increase the spoiler angle just like the big boys, but without needing any integration into the vehicles systems. Or bolts, for that matter.

It’s unlikely that the braking force is enough to slow down the vehicle though, given that it’s not enough to pop the suction cups holding it to the trunk lid. But does it have the “wow” factor that it was designed to induce? Spoiler Alert: It does!

As it turns out, this isn’t the first adjustable spoiler featured here at Hackaday, and this adjustable spoiler on a car that’s made for actual racing is quite interesting.

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3D Printed Circular Prototype Performance Prop Captivates Circus Spectators

February 2, 2022 by Ryan Flowers 12 Comments

When mathematically inspired maker [Henry Segerman] conspired with circus performer and acrobat [Marcus Paoletti] to advance the craft of acrobatics in round metal objects (such as cyr wheels and German Wheels), they came up with a fascinating concept that has taken shape in what [Henry] calls the Tao-Line.

Similar performance devices go in a straight line or can be turned on edge, but the Tao-Line is far more nimble. This is because the Tao-Line is not a continuous cylinder, but rather is made up of numerous circular shapes that allow the Tao-Line to be turned and inverted at different points in its rotation.

While a circus prop might not be your average Hackaday fare, it’s noteworthy because the Tao-Line started off as a 3D printed prototype, which was then turned into the metal fabrication you see in the video below the break. It’s an excellent example of how modeling complex shapes as a physical product- not just a 3D model on the screen- can be helpful in the overall design and construction of the full scale piece.

If you’re looking to build something that’s under the big top but not quite so over the top, you might enjoy this mixed-media digital clock. Thanks to [Keith] for the great tip. Be sure to submit send your cool finds via the Tip Line!

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Monitor For Bedridden Patients Aims To Improve Care

January 26, 2022 by Ryan Flowers 11 Comments

One of the joys of being a Maker and Hacker is solving problems and filling needs. When you can do both, well, that’s something special. [rodrigo.mejiasz]’s project surely fits into that special category of solving a problem and filling a dire need with his Bedridden Patient Monitor.

While [Rodrigo]’s project page does not specify his motivation for creating this project, one only needs to look as far as their local hospital ward or senior care facility to understand why this device is so wonderful. Healthcare workers and caregivers are stretched paper thin, and their attention is being constantly interrupted.

This is where the Bedridden Patient Monitor comes in. A healthy person can reposition themselves if they are uncomfortable, but bedridden patients cannot. It’s not just that a bedridden patient is unable to get out of bed, but that they are unable to move themselves without assistance. The result is a great amount of pain. And if left unchecked, pressure sores can be the result. These are not only extremely unpleasant, but an added danger to a patients health.

The Bedridden Patient Monitor steps in and provides not just an egg-timer like alert, but helps caregivers track a patients position in bed across even several working shifts. This ensures a continuity of care that might otherwise be easy to miss.

The beauty of this build is in its application but also its simplicity: it’s just an Arduino Mega, a TFT shield with its Micro SD card, and the touch screen itself. A few LED’s and a buzzer take care of alerts. A thoughtfully configured interface makes the devices use obvious so that staff can make immediate use of the monitor.

Makers have a long history diving into the medical field, such as this stab wound treatment device that won the Dyson award in 2021.

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