A wafer being loaded into an electron microscope

Using Electron Beams To Draw Tiny Shapes Onto Silicon

December 5, 2022 by Robin Kearey 11 Comments

Over the past few years we’ve seen several impressive projects where people try to manufacture integrated circuits using hobbyist tools. One of the most complex parts of this process is lithography: the step in which shapes are drawn onto a silicon wafer. There are several ways to do this, all of them rather complicated, but [Zachary Tong] over at Breaking Taps has managed to make one of them work quite well. He shares the results of his electron-beam lithography experiments in his latest video (embedded below).

In e-beam lithography, or EBL, shapes are drawn onto a wafer using an electron beam in a vacuum chamber. This is a slow process compared to optical lithography, as used in mass production, but it is reasonably simple and very flexible. [Zach] decided to use his electron microscope as an e-beam litho machine; although not designed for lithography, it has the same basic components as a real EBL machine and can act as a substitute with a bit of software tweaking.

An AFM image of Rick Astley — [Zach] also has an atomic force microscope, which he used to make these beautiful images.

The first step is to coat a wafer with a layer of e-beam resist. [Zach] used PMMA, commonly known as acrylic plastic, and applied it using spin coating after dissolving it in anisole. He then placed the wafer into the electron microscope and used it to scan an image. The image was then developed by rinsing the wafer in cold isopropyl alcohol.

[Zach] explains the whole process in detail in his video, including how he tuned all the parameters like resist thickness, beam strength, exposure time and development time, as well as the software tricks needed to persuade the microscope to function as a litho machine. In his best runs he managed to draw lines with a width of about 100 nanometers, which is seriously impressive for such a relatively simple setup.

These e-beam lithography experiments follow on from [Zach]’s earlier research using lasers. Homebrew IC expert Sam Zeloof has also used electron beams in his work. Thanks for the tip, [smellsofbikes]!

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A repair stand for bicycles with an integrated scale

DIY Repair Stand Holds Your Bike And Weighs It

December 4, 2022 by Robin Kearey 24 Comments

If you’ve ever done maintenance or repair work on your bicycle, you’ll know that positioning a bike in your workshop isn’t trivial. You can use your bike’s kickstand, or lean it against a wall, but then you can’t work on the wheels. You can place it upside-down, but then the shifters and brake levers are hard to reach. You can hang it from the ceiling, but then you first need to install hooks and cables in hard-to-reach places. Ideally you’d want to have one of those standing clamp systems that the pros use, but their price is typically beyond a hobbyist’s budget.

Or at least, that’s how it used to be. As [Dane Kouttron] discovered, a simple wall-mounted bike clamp can be had for as little as $35 on eBay, and can easily be converted into a smart mobile repair stand. [Dane] fashioned an adjustable stand from some steel pipes he had lying around, and 3D-printed an adapter bracket to mount the bike clamp on it. This worked fine, but why stop at a simple clamp when you can expand it with, say, an integrated scale to weigh your bikes while you work on them? Continue reading “DIY Repair Stand Holds Your Bike And Weighs It” →

Simple ATX Bench Power Supply Adds Variable Output

December 1, 2022 by Lewin Day 24 Comments

A benchtop power supply is a key thing to have for any aspiring electronics hacker. While you can always buy one, plenty of us have old computer PSUs lying around that could do a fine job themselves. [Frugha] decided to whip up a neat 3D-printed design for converting any ATX PSU into a usable bench unit.

The design features banana plugs outputting +12V, -12V, +5V, and +3.3V, with all outputs appropriately fused for safety. There’s also a fused stepdown converter used to supply variable voltages as needed. Its original trimpot was replaced with a multi-turn pot for ease of control. To make everything work, a load resistor on the 5V circuit makes the power supply think it’s hooked up to a motherboard. It’s all wrapped up in a neat slant-sided 3D-printed case that fits onto the ATX power supply itself.

The result is a neat and tidy power supply built out of readily-available components. We particularly like the addition of the stepdown converter – most ATX-based projects don’t offer variable output, which can nonetheless come in handy.

We’ve seen some other great builds along these lines before, too. If you’ve been cooking up your own homebrew power supply, don’t hesitate to share it on the tipsline!

Desktop-Sized Fully Automatic Loom Is An Electromechanical Marvel

November 28, 2022 by Robin Kearey 22 Comments

Weaving is one of the oldest crafts in the world, and was also among the first to be automated: the Industrial Revolution was in large part driven by developments in loom technology. [Roger de Meester] decided to recreate that part of the industry’s history, in a way, by building his own desktop-sized, fully automatic loom. After a long career in the textiles industry he’s quite the expert when it comes to weaving, and as you’ll see he’s also an expert machine builder.

[Roger]’s loom is of a specific type called a dobby loom, which means that the vertical threads (the warp) can be moved up and down in various ways to create different patterns in the fabric. The horizontal wires (the weft) are created by a shuttle moving left and right, carrying a bobbin that unspools as it travels. A comb-shaped plate (the reed) then fixes the fresh weft in its place. [Roger]’s videos (embedded below) clearly show this mechanism in action, as well as the loom’s overall design.

A detail of an automatic loom, showing the end of the weft being clamped as the shuttle starts its run — A clamp hold the end of the weft as the shuttle starts its run

The 3D printed shuttle is moved back and forth through the warp by a belt-driven system that grabs the magnetic end of the shuttle. Revolving storage drums on either side of the machine enable the use of different thread colors for each shuttle run. Shuttles are exchanged by a robotic arm that picks them up and places them onto the track; there’s a clamp that grabs the end of the thread as the shuttle starts its run, and a wire cutter to detach it when the shuttle is up for replacement.

This intricate mechanical dance is controlled by a set of Arduino Megas and Nanos. They drive all the servos, DC motors, and steppers while reading out an array of sensors and switches. The system can even detect several faults: the weft is checked for proper tension after each cycle, shuttles with empty bobbins are automatically discarded, while a laser keeps an eye on the warp to ensure none of the threads have snapped.

The entire machine is of [Roger]’s own design; apart from 3D-printed and CNC-machined parts, he also re-used components from various pieces of discarded machinery. His ultimate purpose is to use this machine to make specialized fabrics for medical or industrial use: for example, it can use conductive threads to make fabrics with built-in sensors.

Although this isn’t the first DIY automatic loom we’ve featured, it’s definitely the most advanced. Previous examples, like this 3D-printed miniature version or this neat computer-controlled one can’t really compare to [Roger]’s 26 cm reed width and wide customizability. If you prefer to keep things a bit simpler, you can also use a 3D-printer to directly print certain fabrics.

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A Handy OSHW USB Cable Tester For Your Toolkit

November 20, 2022 by Tom Nardi 22 Comments

There’s no shame in admitting you’ve been burned by a cheapo USB cable — ever since some bean counter realized there was a few cents to be saved by producing “power only” USB cables, no hardware hacker has been safe. But with this simple tester from [Álvaro Prieto] in your arsenal, you’ll never be fooled again.

It’s about as straight-forward a design as possible, utilizing nothing more than a two dozen LEDs, their associated resistors, and a common CR2032 coin cell. Simply plugging both sides of your cable into the various flavors of USB connectors on the tester will complete the necessary circuits to light up the corresponding LEDs, instantly telling you how many intact wires are inside the cable. So whether you’re dealing with some shady cable that doesn’t have the full complement of conductors, or there’s some physical damage that’s severed a connection or two, you’ll know at a glance.

A sage warning for most of the devices we build.

Obviously the tester is designed primarily for the 24 pins you’ll find in a proper USB-C connector, but it’s completely backwards compatible with older cables and connectors. We appreciate that he even included the chunky Type B connector, which we’ve always been fond of thanks to its robustness compared to the more common Mini and Micro variants.

Keep in mind though that this tester will only show you if there’s a connection between two pins, it won’t verify how much power it can actually handle. For that, you’ll need some extra equipment.

See The Forbidden Cigarette Machine In Action

November 20, 2022 by Elliot Williams 64 Comments

[Fraens] has been designing a number of fantastic 3D printed machines and making great videos that demonstrate how they work. The last installment was an automatic cigarette stuffing machine, and it’s got a number of pretty complex motions, and somehow manages to get the job done.

While [Fraens] usually uploads STL files for all of his machines, this one is forbidden! Selling automatic cigarette loaders is illegal in Europe, and it’s not clear how close to the legal edge posting them up on Thingiverse is. So until the legal dust settles, you’re going to have to be content with the fantastic video, also embedded below.

But honestly, the devil’s sticks aren’t good for your health anyway, and you’re probably just in it for the mechanicals. Think for a moment about the problem – you’ve got a hopper of tobacco fibers that all like to stick together, and you need to pack them into an easily squished lightweight paper tube. These tubes aren’t easy to handle either. The solution to both of these calls for solenoid-powered tappers that agitate both into place.

There’s also a 3D printed rack and pinion to do the pushing, and a cool stepper-driven revolver mechanism to put the empty papers into just the right place. The machine leans heavily on 3D printing, but also on simple hardware-store parts like aluminum and brass tubes. [Fraens]’s builds are always simple but simultaneously very slick, and you’ll learn a lot from watching it all go together.

And when you’re done, check out some others from [Fraens]. We’ve been impressed by his sewing machine, braiding machine, and even a power loom.

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A PCB with several points highlighted by a projection system

Augmented Reality Workbench Helps You To Debug Your Boards

November 18, 2022 by Robin Kearey 17 Comments

No matter how advanced your design skills, the chances are you’ll need to spend some time chasing bugs in your boards after they come back from the assembly house. Testing and debugging a PCB typically involves a lot of cross-checking between the board, the layout and the schematic, which quickly becomes tiresome even for mildly complex designs. To make this task a bit easier, [Ishan Chatterjee] and colleagues at the University of Washington have designed the Augmented Reality Debugging Workbench, or ARDW for short.

The ARDW is a setup consisting of a lab workbench with an antistatic mat, a selection of measurement instruments and a PC. You can simply place your board on the bench, open the schematic and layout in KiCAD and start measuring and debugging your design as you normally would, but the real magic happens when you select a new icon in KiCAD that exports the schematic and layout to the ARDW system. From that moment, you can select components in your schematic and have them highlighted not only on the layout, but on the physical board in front of you as well. This is perhaps best demonstrated visually, as the team members do in the video embedded below.

The real-life highlighting of components is achieved thanks to a set of cameras that track the motion of everything on the desk as well as a video projector that overlays information on top of the PCB. All of this enables a variety of useful debugging features: for example, there’s an option to highlight pin one on all components, enabling a simple visual check of each component’s orientation. You can select all Do Not Populate (DNP) instances and immediately see if all highlighted pads are empty. If you’re not sure which component you’re looking at, just point at it with your multimeter probe and it’s highlighted on the schematic and layout. You can even place your probes on a net and automatically log the voltage for future reference, thanks to a digital link between the multimeter and the ARDW software.

In addition to designing and building the ARDW, the team also performed a usability study using a group of human test subjects. They especially liked the ability to quickly locate components on crowded boards, but found the on-line measurement system a bit cumbersome due to its limited positional accuracy. Future work will therefore focus on improving the resolution of the projected image and generally making the system more compact and robust. All software is freely available on the project’s GitHub page, and while the current system looks a little complex for hobbyist use, we can already imagine it being a useful tool in production environments.

It’s not even the first time augmented reality has been used for PCB debugging: we saw a somewhat similar system at the 2019 Hackaday Superconference. AR can also come in handy during the design and prototyping phase, as demonstrated by this AR breadboard.

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