Get Up Close to your Soldering with a Pi Zero Microscope

Do your Mark 1 Eyeballs no longer hold their own when it comes to fine work close up? Soldering can be a literal pain under such conditions, and even for the Elf-eyed among us, dealing with pads at a 0.4-mm pitch is probably best tackled with a little optical assistance. When the times comes for a little help, consider building a soldering microscope from a Pi Zero and a few bits and bobs from around the shop.

Affordable commercial soldering scopes aren’t terribly hard to come by, but [magkopian] decided to roll his own by taking advantage of the streaming capabilities of the Raspberry Pi platform, not to mention its affordability. This is a really simple hack — nothing is 3D-printed or custom milled. The stage base is a simple aluminum project box for heat resistance and extra weight, and the arm is a cheap plastic dial caliper. The PiCam is mounted to the sliding jaw of the caliper on a scrap of plastic ruler. The lens assembly of the camera needs to be hacked a little to change the focal length to work within 10 centimeters or so; alternatively, you could splurge and get a camera module with an adjustable lens. The Pi is set up for streaming, and your work area is presented in glorious, lag-free HDMI video.

Is [magkopian]’s scope going to give you the depth perception of a stereo microscope? Of course not. But for most jobs, it’ll probably be enough, and the fact that it can be built on the cheap makes it a great hack in our book.

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Model Sputnik Finds its Voice After Decades of Silence

As we approach the 60th anniversary of the human race becoming a spacefaring species, Sputnik nostalgia will no doubt be on the rise. And rightly so — even though Sputnik was remarkably primitive compared to today’s satellites, its 1957 launch was an inflection point in history and a huge achievement for humanity.

The Soviets, understandably proud of their accomplishment, created a series of commemorative models of Earth’s first artificial moon as gifts to other countries. How one came into possession of the Royal Society isn’t clear, but [Fran Blanche] found out about it through a circuitous route detailed in the video below, and undertook to reproduce the original electronics from the model that made the distinctive Sputnik beeps.

The Royal Society’s version of the model no longer works, but luckily it came with a schematic of the solid-state circuit used to emulate the original’s vacuum-tube guts. Intent on building the circuit as close to vintage as possible and armed with a bag of germanium transistors from the 60s, [Fran] worked through the schematic, correcting a few issues here and there, and eventually brought the voice of Sputnik back to life.

If you think we’ve covered Sputnik’s rebirth before, you may be thinking about our article on how some hams rebuilt Sputnik’s guts from a recently uncovered Soviet-era schematic. [Fran]’s project just reproduces the sound of Sputnik — no license required!

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Laser Surgery: Expanding the Bed of a Cheap Chinese Laser Cutter

Don’t you just hate it when you spend less than $400 on a 40-watt laser cutter and it turns out to have a work area the size of a sheet of copy paper? [Kostas Filosofou] sure did, but rather than stick with that limited work envelope, he modified his cheap K40 laser cutter so it has almost five times the original space.

The K40 doesn’t make any pretenses — it’s a cheap laser cutter and engraver from China. But with new units going for $344 on eBay now, it’s almost a no-brainer. Even with its limitations, you’re still getting a 40-watt CO2 laser and decent motion control hardware to play with. [Kostas] began the embiggening by removing the high-voltage power supply from its original space-hogging home to the right of the work area. With that living in a new outboard enclosure, a new X-Y gantry of extruded aluminum rails and 3D-printed parts was built, and a better exhaust fan was installed. Custom mirror assemblies were turned, better fans were added to the radiator, and oh yeah — he added a Z-axis to the bed too.

We’re sure [Kostas] ran the tab up a little on this build, but when you’re spending so little to start with, it’s easy to get carried away. Speaking of which, if you feel the need for an even bigger cutter, an enormous 100-watt unit might be more your style.

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Hackaday Prize Entry: A Complete Suite Of Biomedical Sensors

The human body has a lot to tell us if we only have the instruments to listen. Unfortunately, most of the diagnostic gear used by practitioners is pricey stuff that’s out of range if you just want to take a casual look under the hood. For that task, this full-featured biomedical sensor suite might come in handy.

More of an enabling platform than a complete project, [Orlando Hoilett]’s shield design incorporates a lot of the sensors we’ve seen before. The two main modalities are photoplethysmography, which uses the MAX30101 to sense changes in blood volume and oxygen saturation by differential absorption and reflection of light, and biopotential measurements using an instrumentation amplifier built around an AD8227 to provide all the “electro-whatever-grams” you could need: electrocardiogram, electromyogram, and even an electrooculogram to record eye movements. [Orlando] has even thrown on temperature and light sensors for environmental monitoring.

[Orlando] is quick to point out that this is an educational project and not a medical instrument, and that it should only ever be used completely untethered from mains — battery power and Bluetooth only, please. Want to know why? Check out the shocking truth about transformerless power supplies.

Thanks to [fustini] for the tip.

Little Laser Light Show is Cleverly Packaged, Cheap to Build

We’re suckers for any project that’s nicely packaged, but an added bonus is when most of the components can be sourced cheaply and locally. Such is the case for this little laser light show, housed in electrical boxes from the local home center and built with stuff you probably have in your junk bin.

When we first came across [replayreb]’s write-up and saw that he used hard drives in its construction, we assumed he used head galvanometers to drive the mirrors. As it turns out, he used that approach in an earlier project, but this time around, the hard drive only donated its platters for use as low mass, first surface mirrors. And rather than driving the mirrors with galvos, he chose plain old brushed DC motors. These have the significant advantage of being cheap and a perfect fit for 3/4″ EMT set-screw connectors, designed to connect thin-wall conduit, also known as electromechanical tubing, to electrical boxes and panels. The motors are mounted to the back and side of the box so their axes are 90° from each other, and the mirrors are constrained by small cable ties and set at 45°. The motors are driven directly by the left and right channels of a small audio amp, wiggling enough to create a decent light show from the laser module.

We especially like the fact that these boxes are cheap enough that you can build three with different color lasers. In that case, an obvious next step would be bandpass filters to split the signal into bass, midrange, and treble for that retro-modern light organ effect. Or maybe figuring out what audio signals you’d need to make this box into a laser sky display would be a good idea too.

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Building a Metalworking Vise, Layer by Layer

Machine shop wisdom says the lathe is the king of machine tools. We ascribe to that belief, although the common aphorism that the lathe is the only tool that can make copies of itself seems a bit of a stretch. But in the shadow of the almighty lathe is a tool without which even the simplest projects would be vastly more difficult: the lowly vise. Trouble is, finding a good vise can be a tall order. So why not take matters into your own hands and build this very sturdy vise from scratch?

Most commercially available vises are made from a couple of large castings, but as complete as [MakeItExtreme]’s metalworking shop has become, casting molten iron is not a tool in their kit — yet. So they turned back to what they know and welded up the body and jaw of the vise from mild steel. The video below shows the long sessions of welding and grinding that bring the body and the jaw into being, in the process consuming miles of MIG wire. The main screw is cut from stainless steel and threaded with the correct Acme form for such a high load application, especially given the mechanical advantage the long handle provides. The jaws have dovetails for replaceable inserts, too, which is a nice touch that’s hard to find on commercial units.

Vises on Hackaday tend to the lighter duty varieties, such as a 3D-printed vise, the Stickvise for PCBs, or even a fancied-up woodworking vise. It’s nice to see a heavy metal build for a change.

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Smart Child Seat Aims to Prevent Tragedy

For most of us, a memory lapse is as harmless as forgetting to bring the garbage to the curb, or maybe as expensive as leaving a cell phone and cup of coffee on the roof of the car before driving off. But when the toddler sleeping peacefully in the car seat slips your mind in the parking lot, the results can be deadly.

We have no doubt that child detection systems will soon be standard equipment on cars, like backup cameras and trunk-escape levers are now. Not willing to wait, [ayavilevich] came up with his own car occupancy sensor for child seats (Update: We originally linked to the Instructable but [ayavilevich] wrote in and mentioned this is actual Hackaday Prize entry and he’s looking for more people to get involved in the project).

Dubbed Fochica, for “Forgotten Child in Car Alert,” the system is clearly a proof of concept right now, but it has potential. The Arduino Uno senses Junior’s presence in the car seat with a homebrew capacitive sensor under the padding of the seat and a magnetic reed switch in the chest harness buckle. An Android app on a smartphone pairs with a BLE module to get the sensors’ status, and when the phone goes out of Bluetooth range while the seat is occupied, the app sounds an alarm. Simple, but effective.

We like how well [ayavilevich] thought this through. Systems like this are best left uncomplicated, so any improvements he makes should probably concentrate on engineering a reliable, fieldable device. Another hack we’ve presented in the kid-safety space is fast stairwell lights for a visually impaired girl, which might provide some ideas.

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