Building A 3D Printed Scanning Tunneling Microscope

September 30, 2024 by Dave Rowntree 12 Comments

YouTuber [MechnicalRedPanda] has recreated a DIY STM hack we covered about ten years ago, updating it to be primarily 3D-printed, using modern electronics, making it much more accessible to many folks. This simple STM setup utilises a piezoelectric actuator constructed by deliberately cutting a piezo speaker into four quadrants. With individual drive wires attached to the four quadrants. [MechPanda] (re)discovered that piezoelectric ceramic materials are not big fans of soldering heat. Still, in the absence of ultrasonic welding equipment, he did manage to get some wires to take to the surface using low-temperature solder paste.

As you can tell, you can only image conductive samples

A makeshift probe holder was glued on the rear side of the speaker actuator, which was intended to take a super sharp needle-like piece of tungsten wire. Putting the wire in tension and cutting at a sharp angle makes it possible with many attempts to get some usable points. Usable, in this instance, means sharp down the atomic level. The sample platform, actuator mount and all the connecting parts are 3D-printed with PA-CF. This is necessary to achieve enough mechanical stability with normal room temperature fluctuations. Three precision screws are used to level the two platforms in a typical kinematic mount structure, which looks like the only hard-to-source component. A geared stepper motor attached to the probe platform is set up to allow the probe to be carefully advanced towards the sample surface. Continue reading “Building A 3D Printed Scanning Tunneling Microscope” →

Shoot Smooth Video From Your Phone With The Syringe Slider

September 29, 2024 by Donald Papp 5 Comments

We love the idea [Btoretsukuru] shared that uses a simple setup called the Syringe Slider to take smoothly-tracked video footage of small scenes like model trains in action. The post is in Japanese, but the video is very much “show, don’t tell” and it’s perfectly clear how it all works. The results look fantastic!

The device consists of a frame that forms a sort of enclosed track in which one’s mobile phone can slide horizontally. The phone butts up against the plunger of an ordinary syringe built into the frame. As the phone is pushed along, it depresses the plunger which puts up enough resistance to turn the phone’s slide into a slow, even, and smooth glide. Want to fine-tune the resistance and therefore the performance? Simply attach different diameter tips to the syringe.

The results speak for themselves, and it’s a fantastically clever bit of work. There are plenty of DIY slider designs (some of which get amazingly complex) but they are rarely small things that can be easily gotten up close and personal with small subjects like mini train terrain.

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Making A Split-Anode Magnetron

September 26, 2024 by Dave Rowntree 3 Comments

YouTuber The Science Furry has been attempting to make a split-anode magnetron and, after earlier failures, is having another crack at it. This also failed, but they’ve learned where to focus their efforts for the future, and it sure is fun to follow along.

The magnetron theory is simple enough, and we’ve covered this many times, but the split anode arrangement differs slightly from the microwave in your kitchen. The idea is to make a heated filament the cathode, so electrons are ejected from the hot surface by thermionic emission. These are forced into a spiral path using a perpendicular magnetic field. This is a result of the Lorentz force. A simple pair of magnets external to the tube is all that is needed for that. Depending on the diameter of the cavity and the gap width, a standing wave will be emitted. The anodes must be supplied with an alternating potential for this arrangement to work. This causes the electrons to ‘bunch up’ as they cross the gaps, producing the required RF oscillation. The split electrodes also allow an inductor to be added to tune the frequency of this standing wave. That is what makes this special.

The construction starts with pre-made end seals with the tungsten wire electrode wire passing through. In the first video, they attempted to coat the cathode with barium nitrate, but this flaked off, ruining the tube. The second attempt replaces the coiled filament with a straight wire and uses a coating paste made from Barium Carbonate mixed with nitrocellulose in a bit of acetone. When heated, the nitrocellulose and the carbonate will decompose, hopefully leaving the barium coating intact. After inserting the electrode assembly into a section of a test tube and welding on the ends, the vacuum could be pulled and sealed off. After preheating the cathode, some gasses will be emitted into the vacuum, which is then adsorbed into a nearby titanium wire getter. At least, that’s the theory.

Upon testing, this second version burned out early on for an unknown reason, so they tried again, this time with an uncoated cathode. Measuring the emission current showed only 50 uA, which is nowhere near enough, and making the filament this hot caused it to boil off and coat the tube! They decide that perhaps this is one step too many and need to experiment with the barium coating by making simpler diode tubes to get the hang of the process!

If this stuff is over your head, you need a quick history lesson about the magnetron. Next check out this teardown. Finally, we have covered DIY magnetrons before, like this excellent DIY magnetron-powered plasma sputtering device. Yes, you read that correctly.

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An Espresso Machine For The DIY Crowd

September 15, 2024 by Donald Papp 29 Comments

Want to build your own espresso machine, complete with open-source software to drive it? The diyPresso might be right up your alley.

diyPresso parts, laid out and ready for assembly.

It might not be the cheapest road to obtaining an espresso machine, but it’s probably the most economical way to turn high-quality components (including a custom-designed boiler) and sensors into a machine of a proven design.

Coffee and the machines that turn it into a delicious beverage are fertile ground for the type of folk who like to measure, modify, and optimize. We’ve seen DIY roasters, grinders, and even a manual lever espresso machine. There are also many efforts at modifying existing machines with improved software-driven controls but this is the first time we’ve seen such a focused effort at bringing the DIY angle to a ground-up espresso machine specifically offered as a kit.

Curious to know more? Browse the assembly manual or take a peek at the software’s GitHub repository. You might feel some ideas start to flow for your next coffee hack.

Building A Multi-Purpose Electrochemistry Device

September 13, 2024 by Dave Rowntree 12 Comments

We don’t get enough electrochemistry hacks on these pages, so here’s [Markus Bindhammer] of YouTube/Marb’s lab fame to give us a fix with their hand-built general-purpose electrochemistry device.

The basic structure is made from plyboard cut to size on a table saw and glued’n’screwed together. The top and front are constructed from an aluminium sheet bent to shape with a hand-bender. A laser-printed front panel finishes the aesthetic nicely, contrasting with the shiny aluminium. The electrode holders are part of off-the-shelf chemistry components, with the electrical contacts hand-made from components usually used for constructing stair handrails. Inside, a 500 RPM 12 V DC geared motor is mounted, driving a couple of small magnets. A PWM motor speed controller provides power. This allows a magnetic stirrer to be added for relevant applications. Power for the electrochemical cell is courtesy of a Zk-5KX buck-boost power supply with a range of 0 – 36 V at up to 5 A with both CV and CC modes. A third electrode holder is also provided as a reference electrode for voltammetry applications. A simple and effective build, we reckon!

Over the years, we’ve seen a few electrochemical hacks, like this DIY electroplating pen, a DIY electrochemical machining rig, and finally, a little something about 3D printing metal electrochemically.

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Portable Router Build: Finding An LTE Modem

August 19, 2024 by Arya Voronova 8 Comments

Ever want your project equipped with a cellular interface for a data uplink? Hop in, I have been hacking on this for a fair bit! As you might remember, I’m building a router, I told you about how I picked its CPU board, and learned some lessons from me daily-driving it as a for a bit – that prototype has let me learn about the kind of extra hardware this router needs.

Here, let’s talk about LTE modems for high data throughput, finding antennas to make it all work, and give you a few tips that should generally help out. I’d like to outline a path that increases your chances of finding a modem working for you wonderfully – the devices that we build, should be reliable.

Narrowing It Down

If you look at the LTE modem selection, you might be a little overwhelmed: Simcom, Qualcomm, uBlox, Sierra, Telit, and a good few other manufacturers package baseband chipsets into modules and adjust the chipset-maker-provided firmware. The modems will be available in many different packages, too, many of them solderable, and usually, they will be available on mPCIe cards too. If you want to get a modem for data connections for a project, I argue that you should go for mPCIe cards first, and here’s why.

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Cheap DIY Button Pad Uses Neat Punchcard Trick

August 13, 2024 by Lewin Day 16 Comments

A StreamDeck is effectively a really cool box full of colorful buttons that activate various things on your PC. They’re fun and cool but they’re also something you can build yourself if you’re so inclined. [Jason] did just that for his sim racing setup, and he included some nifty old-school tech as well.

An ESP32 is at the core of the build, listening to button presses and communicating with the PC. However, the build doesn’t actually use regular buttons. Instead, it uses infrared sensors wired up in a matrix. This was an intentional choice, because [Jason] wanted the device to be reconfigurable with different paper card overlays. There are ways to do this with regular buttons too, but it works particularly well with the infrared technique. Plus, each button also gets a Neopixel allowing its color to be changed to suit different button maps.

What’s really neat is that the button maps change instantly when a different overlay card is inserted. [Jason] achieved this with an extra row of infrared sensors to detect punched holes in the bottom of the overlay cards.

Once upon a time, even building your own keyboard was an uphill battle. Today, it’s easier than ever to whip up fun and unique interface devices that suit your own exact needs. That’s a good thing! Video after the break.

Continue reading “Cheap DIY Button Pad Uses Neat Punchcard Trick” →