Getting Shredded Plastic…and Legs

September 23, 2023 by Navarre Bartz 10 Comments

While electric motors have taken the drudgery out of many tasks, human power has its advantages. [Precious Plastic Torino] has developed a human-powered plastic shredder for those times when an electric motor just won’t do.

Designed primarily for educational purposes at venues where electricity can be difficult to source, but also useful for off-grid environments, this exercise bike-based shredder can take small pieces of plastic and shred them into tiny pieces suitable for use with any of the other machines in the Precious Plastics ecosystem like their injection molding machine. As with all [Precious Plastics] projects, the files ~~are~~ will be open source; however, there is a six month exclusivity period for Patreon subscribers to help fund development efforts.

The build is relatively simple: take an old exercise bike, remove the unnecessary bits, and run the chain up to drive a shredding mechanism mounted on the front of the bike. We think they should’ve kept the flywheel to help keep the momentum going while shredding but can’t fault them for wanting to keep the prototype as simple as possible. Maybe the next step is getting these in spin classes around the country so people can get their exercise and help recycle in their community at the same time!

If this shredder doesn’t suit your fancy, maybe recycle your plastic with SHREDII or this other DIY effort. If you’d rather generate electricity on your exercise bike, then try building this bike generator.

Continue reading “Getting Shredded Plastic…and Legs” →

DIY Repair Brings An X-Ray Microscope Back Into Focus

September 22, 2023 by Dan Maloney 6 Comments

Aside from idle curiosity, very few of us need to see inside chips and components to diagnose a circuit. But reverse engineering is another story; being able to see what lies beneath the inscrutable epoxy blobs that protect the silicon within is a vital capability, one that might justify the expense involved in procuring an X-ray imager. But what’s to be done when such an exotic and expensive — not to mention potentially deadly — machine breaks down? Obviously, you fix it yourself!

To be fair, [Shahriar]’s Faxitron MX-20 digital X-ray microscope was only a little wonky. It still generally worked, but just took a while to snap into the kind of sharp focus that he needs to really delve into the guts of a chip. This one problem was more than enough to justify tearing into the machine, but not without first reviewing the essentials of X-ray production — a subject that we’ve given a detailed look, too — to better understand the potential hazards of a DIY repair.

With that out of the way and with the machine completely powered down, [Shahriar] got down to the repair. The engineering of the instrument is pretty impressive, as it should be for something dealing with high voltage, heavy thermal loads, and ionizing radiation. The power supply board was an obvious place to start, since electrostatically focusing an X-ray beam depends on controlling the high voltage on the cathode cup. After confirming the high-voltage module was still working, [Shahriar] homed in on a potential culprit — a DIP reed relay.

Replacing that did the trick, enough so that he was able to image the bad component with the X-ray imager. The images are amazing; you can clearly see the dual magnetic reed switches, and the focus is so sharp you can make out the wire of the coil. There are a couple of other X-ray treats, so make sure you check them out in the video below.

Continue reading “DIY Repair Brings An X-Ray Microscope Back Into Focus” →

Printed Upgrades Improve Cheap Digital Microscope

September 19, 2023 by Bryan Cockfield 7 Comments

Digital microscopes used to be something that only labs or universities might have, but as image sensor technology has progressed, the prices have fallen to the point that any classroom or hobbyist can easily obtain a usable device. The only problem is that a lot of features and quality have been lost to make some of these digital microscopes more affordable. In an effort to add some of these creature comforts back into more inexpensive devices, [Marb’s lab] has created a special carriage for one of these microscopes.

The first addition to the microscope is improved lighting. To accomplish this, three LEDs were built into custom housings and wired to a purpose-built LED driver board coupled with a voltage regulator. Two of the LED housings were attached to the end of adjustable arms, allowing them to be pointed in whichever direction is needed. The third is situated directly below the microscope underneath the stage. These are all mounted to a large, sturdy PVC base which also holds an adjustable carriage for the microscope itself. This allows much more fine-tuning of the distance between the sample and the microscope than it otherwise would have had.

For just a few dollars and a little bit of effort, the usability of a device like this is greatly improved. If you want to take the opposite approach and really go all-out for your microscope, though, take a look at these microscopes used for PCB circuit construction and troubleshooting or even this electron microscope for viewing things at a much higher magnification than any optical system would allow.

Continue reading “Printed Upgrades Improve Cheap Digital Microscope” →

Image of the presenter on the podium, in front of the projector screen with graphs shown on it

Supercon 2022: [Alex Whittemore] On Treating Your Sensor Data Well

September 15, 2023 by Arya Voronova 4 Comments

If you build your own devices or hack on devices that someone else has built, you know the feeling of opening a serial terminal and seeing a stream of sensor data coming from your device. However, looking at scrolling numbers gets old fast, and you will soon want to visualize them and store them – which is why experienced makers tend to have a few graph-drawing and data-collecting tools handy, ready to be plugged in and launched at a moment’s notice. Well, if you don’t yet have such a tool in your arsenal, listen to this 16-minute talk by [Alex Whittemore] to learn about a whole bunch of options you might not even know you had!

For a start, there’s the Arduino Serial Plotter that you get for free with your Arduino IDE install, but [Alex] also reminds us of the Mu editor’s serial plotter – about the same in terms of features, but indisputably an upgrade in terms of UX. It’s not the only plotter in town, either – Better Serial Plotter is a wonderful standalone option, with a few features that supercharge it, as [Alex] demonstrates! You don’t have to stop here, however – we can’t always be tethered to our devices’ debugging ports, after all. Continue reading “Supercon 2022: [Alex Whittemore] On Treating Your Sensor Data Well” →

Reverse-engineering The Milwaukee M18 Redlink Protocol

September 15, 2023 by Maya Posch 19 Comments

In an ideal world, every single battery pack for power tools would use the same physical interface and speak a clearly documented protocol with chargers. Since we live in a decidedly less-than-ideal world, we get to enjoy the fun pastime of reverse-engineering the interfaces and protocols of said battery packs.

A recent video from the [Tool Scientist] goes over what is already known about the Milwaukee M18 Redlink protocol, used with the manufacturer’s M18-series of batteries, before diving into some prodding and poking of these packs’ sensitive parts to see what comes out of their interface.

Previously, [Buy It Fix It] shared their findings on Reddit, covering the basic protocol, including the checksum method, but without an in-depth analysis of the entire charging protocol. Meanwhile [Quagmire Repair] performed an in-depth teardown and reverse-engineering of the M18 hardware, including the circuitry of the BMS.

Putting these two things together, [Tool Scientist] was able to quickly get some of his M18 packs strapped down into the analysis chair for both passive analysis, as well as the effect of overvoltage, undervoltage, overheating and freezing the battery pack on the output reported by the battery’s BMS.

One of the lists of commands and response messages obtained by [Tool Scientist] on YouTube.

The result is a rather comprehensive list of instructions obtained under these various conditions, including a fault condition (05) returned by the BMS of one pack indicating its likely demise. Overall, it does not appear to be a particularly special (or well-designed) protocol, but it does make for a good reverse-engineering target, while adding to the body of collective knowledge on these widely available battery packs.

Hopefully the same inertia that prevents people from moving outside the designated power tool ecosystem due to the incompatible battery packs will also ensure that this level of knowledge will remain relevant for the foreseeable future, especially since the manufacturers of knock-off battery packs seem rather unwilling to share the results of their own reverse-engineering efforts.

Continue reading “Reverse-engineering The Milwaukee M18 Redlink Protocol” →

Bare Bones Vacuum Forming, Just Add Plastic Plates

September 14, 2023 by Donald Papp 16 Comments

Vacuum forming is a handy thing to be able to do, and [3DSage] demonstrates how to do a bare-bones system that can form anything smaller than a dinner plate with little more than a 3D printed fitting to a vacuum cleaner, a heat gun, and a trip to the dollar store.

Plastic plates from the dollar store make excellent forming sheets, and in a variety of colors.

The 3D printed piece is a perforated table that connects to a vacuum cleaner hose, and [3DSage] mentions elsewhere that he tried a few different designs and this one worked the best. A cardboard box makes an expedient stand. The object being molded goes on the table, and when the vacuum is turned on, air gets sucked down into the holes.

As for the thermoforming itself, all that takes is some cheap plastic plates and a heat gun. Heat the plastic until it begins to droop, then slap it down onto the vacuum table and watch the magic happen. Using plastic plates like this is brilliant. Not only are they economical, but their rim serves as a built-in handle and helps support the sagging plastic.

Thermoforming plastic on a 3D-printed vacuum table and using 3D-printed molds definitely isn’t a system that will be cranking parts out all day long, but as long as one allows time for everything to cool off in between activations, it’ll get the job done. Nylon will hold up best but even PLA can be serviceable.

Watch it in action in the video embedded below. The video is actually about [3DSage] making adorable Game Boy themed s’mores, but here’s a link to the exact moment the vacuum forming part happens.

Continue reading “Bare Bones Vacuum Forming, Just Add Plastic Plates” →

A homebrew machine that dips a piece of wire into an etching solution

Homebrew Probe Tip Etcher Makes Amazingly Sharp Needles

September 14, 2023 by Robin Kearey 17 Comments

There’s a simple reason why high-tech gadgets like PCs, TVs and smartphones are so cheap: they’re mass-produced. By spreading out huge engineering costs over equally huge production volumes, the cost per item can remain quite low. The flipside to this is that devices with only a small niche market can be extremely expensive even when they seem quite simple.

[Baird Bankovic], an undergrad student at Penn State University, discovered this when he was working with a scanning tunneling microscope (STM). He noticed that the machines used to make STM probes, a pretty straightforward process, cost north of $7500. This inspired him to make a cheap STM probe etching machine using simple homebrew parts.

If you’re not familiar with scanning tunneling microscopy, here’s how it works in a nutshell: a very sharp tungsten needle is positioned a few nanometers above the sample to be analyzed, and a small voltage is applied between the two. Through an effect known as quantum tunneling, a small current then flows between the probe and the sample. By observing this current and scanning the probe across the sample, a three-dimensional picture of the surface is obtained with sub-nanometer-level resolution.

One of the many factors that determine the quality of the image is the sharpness of the probe. Because a very sharp probe is extremely fragile and prone to oxidation, they are typically made on-site by dipping a piece of tungsten wire into an etchant in one of those costly machines.

That’s exactly what [Baird]’s device does: a Petri dish on a 3D printed frame holds a volume of sodium hydroxide solution, while a jackscrew Z-stage moves a probe holder up and down. A piece of tungsten wire is dipped into the solution and a voltage is applied to start the etching process. Because most of the etching happens at the liquid’s surface, the wire gets progressively thinner at that point until it snaps and the bottom half drops off. When this happens, the current through the wire changes rapidly, which triggers the machine to pull the wire out of the solution and stop the etching process.

The resulting probes have a well-defined sharp tip with an estimated width of about 50 nanometers — pretty impressive for such a simple setup. The entire hardware design is open source and available on [Baird]’s GitHub page for anyone to replicate. Nanometer-sized needles might only seem useful for those with a professional STM setup, but they also come in handy for all kinds of homebrew atomic-scale imaging experiments.

Continue reading “Homebrew Probe Tip Etcher Makes Amazingly Sharp Needles” →