The Fab Lab Next Door: DIY Semiconductors

You think you’ve got it going on because you can wire up some eBay modules and make some LEDs blink, or because you designed your own PCB, or maybe even because you’re an RF wizard. Then you see that someone is fabricating semiconductors at home, and you realize there’s always another mountain to climb.

We were mesmerized when we first saw [Sam Zeloof]’s awesome garage-turned-semiconductor fab lab. He says he’s only been acquiring equipment since October of 2016, but in that short time he’s built quite an impressive array of gear; a spin-coating centrifuge, furnaces, tons of lab supplies and toxic chemicals, a turbomolecular vacuum pump, and a vacuum chamber that looks like something from a CERN lab.

[Sam]’s goal is to get set up for thin-film deposition so he can make integrated circuits, but with what he has on hand he’s managed to build a few diodes, some photovoltaic cells, and a couple of MOSFETs. He’s not growing silicon crystals and making his own wafers — yet — but relies on eBay to supply his wafers. The video below is a longish intro to [Sam]’s methods, and his YouTube channel has a video tour of his fab and a few videos on making specific devices.

[Sam] credits [Jeri Ellsworth]’s DIY semiconductor efforts, which we’ve covered before, as inspiration for his fab, and we’re going to be watching to see where he takes it from here. For now, though, we’d better boost the aspiration level of our future projects.

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Ham Goes Nuts for Tiny Transmitter

What’s the minimal BOM for a working amateur radio transmitter? Looks like you can get away with seven parts, or eight if you include the walnut. You’ve got to have a walnut.

Some hams really love the challenge of QRP, or the deliberate use of low-power transmitters to provide a challenge to making long-distance contacts. We’ve covered the world of QRP before and noted that while QRP rigs don’t throw a lot of power, it doesn’t mean that they need to be simple. Some get quite complex and support many different modulation schemes, even digital modes. With only a single 2N3904 transistor,  [Jarno (PA3DMI)]’s tiny transmitter won’t do much more than send Morse using CW modulation, but given that it’s doing so from inside a walnut shell, we have no complaints. The two halves of the shell are hinged together and hold a scrap of perfboard for the simple quartz crystal oscillator. The prototype was tuned outside the shell,  and the 9-volt battery is obviously external, but aside from that it’s nothing but nuts.

We’d love to see [Jarno] add a spring to the hinge and contacts on the shell halves so no keyer is required. Who knows? Castanet-style keying might be all the rage with hams after that.

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iPhone Brain Surgery

You think you’re good at soldering? Can you solder a CPU? A CPU inside an iPhone? A decapped CPU inside an iPhone? Can you solder inside a decapped CPU inside of an iPhone?

If you can’t, fear not – someone can, and we found him or her courtesy of a video that [Bunnie Huang] tweeted a while back. There’s not much information in the video, but from what we can gather it comes from an outfit called G-Lon Technology in Guang Zhou. Their Facebook page suggests that they teach cellphone repair, and if they take their repairs this far, we’d say the students are getting their tuition’s worth.

The reason for the repair is unclear, although the titles refer to a “CPU to U0301 AP31 AR31 broken repair,” which we take to refer to a boot error that can be repaired by exposing a couple of pads inside the CPU and wiring them to another chip. We’d love to hear comments from anyone familiar with the repair, but even in the absence of a clear reason for undertaking this, the video is pretty impressive. The epoxy cap of the CPU is painstakingly ground away under a microscope, then tiny tools are used to scrape down to the correct layers. Solder mask is applied, hair-thin wires are tacked to the pads, and a UV-curing resin is applied to fill the CPU’s new gaping hole and to stabilize the wires. It seems like a lot of work to save an iPhone, but it sure is entertaining to watch.

Can’t get enough of poking around the innards of chips? We’ve got decapping stories aplenty: one, two, and three that you might like. We’ve even covered at least one CPU internal repair before too.

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Bring Saturday Mornings Back to Life with this Cartoon Server

It was an American ritual for over four decades: wake up early on Saturday morning, prepare a bowl of sugar, and occupy the couch for four glorious hours of cartoons. The only interruptions came when the least-significant sibling had to be commanded to get up to change the channel to one of the two other networks, or when your mom decided to vacuum the TV room. It was a beautiful ritual, but now it’s gone.

Or is it? If you really want to recapture your misspent youth, you can try this Raspberry Pi multi-channel cartoon server with retro TV display. [FozzTexx] started with a yard sale 13″ Zenith set, which languished in his shop for want of a mission. When he found a four-channel video modulator, he knew he had the makings of the full channel-changing Saturday morning experience.

Four Raspberry Pis were configured to serve up four separate streams of cartoons from his Plex server, and after a late Friday night of hacking the whole thing together, each stream was ready to go live at 7:00 AM on Saturday. [FozzTexx] thought of everything — from the pre-“broadcast day” test pattern to actual commercials spliced into the cartoons to the static between the channels, it’s all there in low-definition glory. He even printed up faux TV Guide pages! You can watch a brief demo on [FozzTexx]’ Twitter feed, or you can watch the entire 2-hour Periscope feed if you’re feeling nostalgic.

[FozzTexx] chose UHF channels for his “stations,” so if you want to replicate this build it may pay to bone up on analog TV tuner basics. Or if it’s just the retro look you’re going for, this custom case inspired by a 40s TV might be nice to check out.

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What the Flux: How Does Solder Work Anyway?

I’ve been soldering for a long time, and I take pride in my abilities. I won’t say that I’m the best solder-slinger around, but I’m pretty good at this essential shop skill — at least for through-hole and “traditional” soldering; I haven’t had much practice at SMD stuff yet. I’m confident that I could make a good, strong, stable joint that’s both electrically and mechanically sound in just about any kind of wire or conductor.

But like some many of us, I learned soldering as a practical skill; put solder and iron together, observe results, repeat the stuff that works and avoid the stuff that doesn’t. Seems like adding a little inside information might help me improve my skills, so I set about learning what’s going on mechanically and chemically inside a solder joint.

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Own the Night with this Open Source Night Vision Monocular

If you’ve always wanted to see in the dark but haven’t been able to score those perfect Soviet-era military surplus night vision goggles, you may be in luck. Now there’s an open-source night vision monocular that you can build to keep tabs on the nighttime goings-on in your yard.

Where this project stands out is not so much the electronics — it’s really just a simple CCD camera module with the IR pass filter removed, an LCD screen to display the image, and a big fat IR LED to throw some light around. [MattGyver92] seemed to put most of his effort into designing a great case for the monocular, at the price of 25 hours of 3D printer time. The main body of the case is nicely contoured, the eyepiece has a comfortable eyecup printed in NinjaFlex, and the camera is mounted on a ball-and-socket gimbal to allow fine off-axis angle adjustments. That comes in handy to eliminate parallax errors while using the monocular for nighttime walks with both eyes open. One quibble: the faux mil-surp look is achieved with a green filter over the TFT LCD panel. We wonder if somehow eliminating the red and blue channels from the camera might not have been slightly more elegant.

Overall, though, we like the way this project came out, and we also like the way [MattGyver92] bucked the Fusion 360 trend and used SketchUp to design the case. But if walking around at night with a monocular at your face isn’t appealing, you can always try biohacking yourself to achieve night vision.

Plasma Cutter Jig Notches Tubing Quickly and Cleanly

It may be [MakeItExtreme]’s most ambitious build to date. There are a lot of moving parts to this plasma cutter tubing notcher, but it ought to make a fine addition to the shop and open up a lot of fabrication possibilities.

We have to admit to a certain initial bafflement when watching the video below for the first time. We can usually see where [MakeItExtreme]’s builds are going right from the first pieces of stock that get cut, but the large tube with the pressed-in bearing had us scratching our heads. The plan soon became clear — a motorized horizontal rotary table with a hollow quill for the plasma torch leads. There’s a jig for holding the torch itself that can move in and out relative to the table. Cams made of tube sections can be bolted to a fixed platen; a cam follower rides on the cams and moves the torch in and out as the table rotates. This makes the cuts needed to properly fit tubes together — known as fish mouth cuts or saddle cuts. The cams can be removed for straight cuts, and the custom pipe vise can be adjusted to make miter cuts.

All in all a sturdy and versatile build that ought to enable tons on new projects, especially when teamed up with [MakeIt Extreme]’s recent roll bender.

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