MEMS Teardown And Macroscopic Models

March 6, 2023 by Al Williams 18 Comments

There is a bit of a paradox when it comes to miniaturization. When electronics replaced mechanical devices, it was often the case that the electronic version was smaller. When transistors and, later, ICs, came around, things got smaller still. However, as things shrink to microscopic scales, transistors don’t work well, and you often find — full circle — mechanical devices. [Breaking Taps] has an investigation of a MEMS chip. MEMS is short for Micro Electromechanical Systems, which operate in a decidedly mechanical way. You can see the video, which has some gorgeous electron microscopy, below. The best part, though, is the 3D-printed macroscale mechanisms that let you see how the pieces work.

Decapsulating the MPU-6050 was challenging. We usually mill a cavity on the top of an IC and use fuming nitric on a hot plate (under a fume hood) to remove the remaining epoxy. However, the construction of these chips has two pieces of silicon sandwiched together, so you need to fully expose the die to split them apart, so our usual method might not work so well. Splitting them open, though, damaged parts of the chip, so the video shows a composite of several devices.

Continue reading “MEMS Teardown And Macroscopic Models” →

A Lab-Grade Measurement Microphone For Not A Lot

June 8, 2022 by Jenny List 21 Comments

The quality of any measurement can only be as good as the instrument used to gather it, and for acoustic measurements, finding a good enough instrument can be surprisingly difficult. Commonly available microphones can be of good quality, but since they are invariably designed for speech or music, they need not have the flat or wide enough response and low noise figure demanded of an instrumentation microphone.

Microphones for measurement purposes can be had for a very large outlay, but here’s [Peter Riccardi] with a unit designed around an array of MEMS capsules that delivers comparable performance for a fraction of the cost.

The result is both an extremely interesting project for those of us with an interest in audio, and a thorough delve into some aspects of its design for those who are merely curious. It uses four capsules in an effort to cancel out induced electrical noise, and boasts some impressive comparative measurements when tested against a commercial measurement microphone. We could almost see ourselves building this project.

Interested in audio technology? Try our Know Audio series.

Old Printer Becomes Direct Laser Lithography Machine

March 22, 2022 by Dan Maloney 21 Comments

What does it take to make your own integrated circuits at home? It’s a question that relatively few intrepid hackers have tried to answer, and the answer is usually something along the lines of “a lot of second-hand equipment.” But it doesn’t all have to be cast-offs from a semiconductor fab, as [Zachary Tong] shows us with his homebrew direct laser lithography setup.

Most of us are familiar with masked photolithography thanks to the age-old process of making PCBs using photoresist — a copper-clad board is treated with a photopolymer, a mask containing the traces to be etched is applied, and the board is exposed to UV light, which selectively hardens the resist layer before etching. [Zach] explores a variation on that theme — maskless photolithography — as well as scaling it down considerably with this rig. An optical bench focuses and directs a UV laser into a galvanometer that was salvaged from an old laser printer. The galvo controls the position of the collimated laser beam very precisely before focusing it on a microscope that greatly narrows its field. The laser dances over the surface of a silicon wafer covered with photoresist, where it etches away the resist, making the silicon ready for etching and further processing.

Being made as it is from salvaged components, aluminum extrusion, and 3D-printed parts, [Zach]’s setup is far from optimal. But he was able to get some pretty impressive results, with features down to 7 microns. There’s plenty of room for optimization, of course, including better galvanometers and a less ad hoc optical setup, but we’re keen to see where this goes. [Zach] says one of his goals is homebrew microelectromechanical systems (MEMS), so we’re looking forward to that.

Continue reading “Old Printer Becomes Direct Laser Lithography Machine” →

Laser Theremin Turns Your Hand Swooshes Into Music

October 3, 2021 by Joshua Vasquez 10 Comments

In a world where smartphones have commoditized precision MEMS Sensors, the stage is set to reimagine clusters of these sensors as something totally different. That’s exactly what [chronopoulos] did, taking four proximity sensors and turning them into a custom gesture input sensor for sound generation. The result is Quadrant, a repurposable human-interface device that proves to be well-posed at detecting hand gestures and turning them into music.

At its core, Quadrant is a human interface device built around an STM32F0 and four VL6180X time-of-flight proximity sensors. The idea is to stream the measured distance data over as fast as possible from the device side and then transform it into musical interactions on the PC side. Computing distance takes some time, though, so [chronopoulos] does a pipelined read of the array to stream the data into the PC over USB at a respectable 30 Hz.

With the data collected on the PC side, there’s a spread of interactions that are possible. Want a laser harp? No problem, as [chronopoulos] shows how you can “pluck” the virtual strings. How about an orientation sensor? Simply spread your hand over the array and change the angle. Finally, four sensors will also let you detect sweeping gestures that pass over the array, like the swoosh of your hand from one side to the other. To get a sense of these interactions, jump to the video demos at the 2:15 mark after the break.

If you’re curious to dig into the project’s inner workings, [chronopoulos] has kindly put the firmware, schematics, and layout files on Github with a generous MIT License. He’s even released a companion paper [PDF] that details the math behind detecting these gestures. And finally, if you just want to cut to the chase and make music of your own, you can actually snag this one on Tindie too.

MEMs sensors are living a great second life outside our phones these days, and this project is another testament to the richness they offer for new project ideas. For more MEMs-sensor-based projects, have a look at this self-balancing robot and magic wand.

Continue reading “Laser Theremin Turns Your Hand Swooshes Into Music” →

Scanning electron micrograph of a microfabricated lens array

Getting A Fly’s-Eye View With Microfabricated Lens Arrays

September 7, 2021 by Dan Maloney 11 Comments

Atomic force microscopy, laser ablation, and etching with a witches brew of toxic chemicals: sounds like [Zachary Tong] has been playing in the lab again, and this time he found a way to fabricate arrays of microscopic lenses as a result.

Like many of the best projects, [Zach]’s journey into micro-fabrication started with a happy accident. It happened while he was working on metal-activated chemical etching (MACE), which uses a noble metal catalyst to selectively carve high-aspect-ratio features in silicon. After blasting at a silver-coated silicon wafer with a laser, he noticed the ablation pits were very smooth and uniform after etching. This led him to several hypotheses about what was going on, all of which he was able to test.

The experiments themselves are pretty interesting, but what’s really cool is that [Zach] realized the smooth hemispherical pits in the silicon could act as a mold for an array of microscopic convex lenses. He was able to deposit a small amount of clear silicone resin into the mold by spin-coating, and (eventually) transfer the microlens array to a glass slide. The lenses are impressively small — hundreds of them over only a couple hundred square microns — and pretty well-formed. There’s always room for improvement, of course, but for an initial attempt based on a serendipitous finding, we’d call it a win. As for what good these lenses are, your guess is as good as ours. But novel processes like these tend to find a way to be useful, and the fact that this is coming out of a home lab doesn’t change that fact.

We find this kind of micro-fabrication fascinating. Whether it’s making OLED displays, micro-machining glass with plasma, or even rolling your own semiconductors, we can’t get enough of this stuff.

Continue reading “Getting A Fly’s-Eye View With Microfabricated Lens Arrays” →

Hackaday Links: June 13, 2021

June 13, 2021 by Dan Maloney 6 Comments

When someone offers to write you a check for $5 billion for your company, it seems like a good idea to take it. But in the world of corporate acquisitions and mergers, that’s not always the case, as Altium proved this week when they rebuffed a A$38.50 per share offer from Autodesk. Altium Ltd., the Australian company whose flagship Altium Designer suite is used by PCB and electronic designers around the world, said that the Autodesk offer “significantly undervalues” Altium, despite the fact that it represents a 42% premium of the company’s share price at the end of last week. Altium’s rejection doesn’t close the door on ha deal with Autodesk, or any other comers who present a better offer, which means that whatever happens, changes are likely in the EDA world soon.

There were reports this week of a massive explosion and fire at a Chinese polysilicon plant — sort of. A number of cell phone videos have popped up on YouTube and elsewhere that purport to show the dramatic events unfolding at a plant in Xinjiang province, with one trade publication for the photovoltaic industry reporting that it happened at the Hoshine Silicon “997 siloxane” packing facility. They further reported that the fire was brought under control after about ten hours of effort by firefighters, and that the cause is under investigation. The odd thing is that we can’t find a single mention of the incident in any of the mainstream media outlets, even five full days after it purportedly happened. We’d have figured the media would have been all over this, and linking it to the ongoing semiconductor shortage, perhaps erroneously since the damage appears to be limited to organic silicone production as opposed to metallic silicon. But the company does supply something like 17% of the world’s supply of silicon metal, so anything that could potentially disrupt that should be pretty big news.

It’s always fun to see “one of our own” take a project from idea to product, and we like to celebrate such successes when they come along. And so it was great to see the battery-free bicycle tire pressure sensor that Hackaday.io user CaptMcAllister has been working on make it to the crowdfunding stage. The sensor is dubbed the PSIcle, and it attaches directly to the valve stem on a bike tire. The 5-gram sensor has an NFC chip, a MEMS pressure sensor, and a loop antenna. The neat thing about this is the injection molding process, which basically pots the electronics in EDPM while leaving a cavity for the air to reach the sensor. The whole thing is powered by the NFC radio in a smartphone, so you just hold your phone up to the sensor to get a reading. Check out the Kickstarter for more details, and congratulations to CaptMcAllister!

We’re saddened to learn of the passing of Dale Heatherington last week. While the name might not ring a bell, the name of his business partner Dennis Hayes probably does, as together they founded Hayes Microcomputer Products, makers of the world’s first modems specifically for the personal computer market. Dale was the technical guru of the partnership, and it’s said that he’s the one who came up with the famous “AT-command set”. Heatherington only stayed with Hayes for seven years or so before taking his a $20 million share of the company and retiring, which of course meant more time and resources to devote to tinkering with everything from ham radio to battle bots. ATH0, Dale.

Macro Model Makes Atomic Force Microscopy Easier To Understand

June 12, 2021 by Dan Maloney 6 Comments

For anyone that’s fiddled around with a magnifying glass, it’s pretty easy to understand how optical microscopes work. And as microscopes are just an elaboration on a simple hand lens, so too are electron microscopes an elaboration on the optical kind, with electrons and magnets standing in for light and lenses. But atomic force microscopes? Now those take a little effort to wrap your brain around.

Luckily for us, [Zachary Tong] over at the Breaking Taps YouTube channel recently got his hands on a remarkably compact atomic force microscope, which led to this video about how AFM works. Before diving into the commercial unit — but not before sharing some eye-candy shots of what it can do — [Zach] helpfully goes through AFM basics with what amounts to a macro version of the instrument.

His macro-AFM uses an old 3D-printer as an X-Y-Z gantry, with a probe head added to the printer’s extruder. The probe is simply a sharp stylus on the end of a springy armature, which is excited into up-and-down oscillation by a voice coil and a magnet. The probe rasters over a sample — he looked at his 3D-printed lattices — while bouncing up and down over the surface features. A current induced in the voice coil by the armature produces a signal that’s proportional to how far the probe traveled to reach the surface, allowing him to map the sample’s features.

The actual AFM does basically the same thing, albeit at a much finer scale. The probe is a MEMS device attached to — and dwarfed by — a piece of PCB. [Zach] used the device to image a range of samples, all of which revealed fascinating details about the nanoscale realm. The scans are beautiful, to be sure, but we really appreciated the clear and accessible explanation of AFM.

Continue reading “Macro Model Makes Atomic Force Microscopy Easier To Understand” →