DIY Power Supply and TS100 Outlet Combo Shows off Great Layout

Here’s a combination of two important electronics workbench tools into a single, cleanly-assembled unit. [uGen] created a DC power supply complete with a plug for the popular TS100 soldering iron, and it looks great! Most of the main components are familiar offerings, like a LM2596 DC to DC buck converter board and a DPS3003 adjustable DC power supply unit (we previously covered a DIY power supply based around the similar DPS5005.) The enclosure is an economical, featureless desktop instrument case whose panels were carefully cut to fit the necessary components. There’s one limitation to the combo: the unit uses a switch to either power an attached TS100 iron, or act as a general DC power supply. It cannot do both at once. So long as one doesn’t mind that limitation, it’s a nice bundle made from very affordable components.

It’s easy for something to look like a hack job, but to look clean and professional involves thoughtful measurement, planning, and assembly. Fortunately, [uGen] has supplied all the drawings and bill of materials for the project so there’s no need to start from scratch. Also, don’t forget that if the capabilities of the DPS power supply units leave you wanting a bit more, there is alternative firmware in the form of OpenDPS; it even offers a remote control feature by adding an ESP8266.

3D Printed Stethoscope Makes the Grade

On the off chance that initiatives like the Hackaday Prize didn’t make it abundantly clear, we believe strongly that open designs can change the world. Putting technology into the hands of the people is a very powerful thing, and depending on where you are or your station in life, can quite literally mean the difference between life and death. So when we saw that not only had a team of researchers developed a 3D printable stethoscope, but released everything as open source on GitHub, it’s fair to say we were pretty interested.

The stethoscope has been in development for several years now, but has just recently completed a round of testing that clinically validated its performance against premium brand models. Not only does this 3D printed stethoscope work, it works well: tests showed its acoustic performance to be on par with the gold standard in medical stethoscopes, the Littmann Cardiology III. Not bad for something the researchers estimate can be manufactured for as little as $3 each.

All of the 3D printed parts were designed in OpenSCAD (in addition to a Ruby framework called CrystalSCAD), which means the design can be evaluated, modified, and compiled into STLs with completely free and open source tools. A huge advantage for underfunded institutions, and in many ways the benchmark by which other open source 3D-printable projects should be measured. As for the non-printed parts, there’s a complete Bill of Materials which even includes links to where you can purchase each item.

The documentation for the project is also exceptional. It not only breaks down exactly how to print and assemble the stethoscope, it even includes multi-lingual instructions which can be printed out and distributed with kits so they can be assembled in the field by those who need them most.

From low-cost ultrasounds to truly personalized prosthetics, the future of open source medical devices is looking exceptionally bright.

[Thanks to Qes for the tip]

A Pin Pusher To Make Life Easier

Picture the scene: you’ve whipped up an amazing new gadget, your crowdfunding campaign has gone well, and you’ve got a couple hundred orders to fill. Having not quite hit the big time, you’re preparing to tackle the production largely yourself. Parts begin to flood in, and you’ve got tube after tube of ICs ready to populate your shiny new PCBs? After the third time, you’re sick and tired of fighting with those irksome little pins. Enter [Stuart] with the answer.

It’s a simple tool, attractively presented. Two pieces of laser cut acrylic are assembled in a perpendicular fashion, creating a vertical surface which can be used to press pins out of IC tubes. [Stuart]’s example has rubber feet, though we could easily see this built into a work surface as well.

The build highlights two universal truths. One, that laser cutters are capable of producing elegant, visually attractive items almost effortlessly, something we can’t say about the garden variety 3D printer. Secondly, all it takes is a few little jigs and tools to make any production process much easier. This is something that’s easy to see in the many factories all over the world – special single-purpose devices that make a weird, tricky task almost effortless.

In DIY production lines, testing is important too – so why not check out this home-spun test jig?

Building a Portable Solar-Powered Spot Welder: Nearly Practical!

Last time, we covered storing and charging a 3000 Farad supercapacitor to build a solar-powered, portable spot welder. Since then, I’ve made some improvements to the charging circuit and gotten it running. To recap, the charger uses a DC-DC buck converter to convert a range of DC voltages down to 2.6 V. It can supply a maximum of 5 A though, and the supercapacitor will draw more than that if allowed to.

Capacitor charge current decreases with time as the capacitor charges. Source: Hyperphysics

After some failed attempts, I had solved that by passing the buck converter output through a salvaged power MOSFET. A spare NodeMCU module provided pulse width modulated output that switched the MOSFET on for controlled periods of time to limit the charging current. That was fine, but a constant-voltage charger really isn’t the right way to load up a capacitor. Because the capacitor plates build up a voltage as it charges, the current output from a constant-voltage charger is high initially, but drops to a very low rate in the end.

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Automatic DIY Wire Stripper

Breadboards are a great way to get started with electronics, they can remove the need for soldering which saves time for beginners who are still getting to grips with the basics of electricity, and they allow quick and easy changes to be made without the risk of melting components. However, they do require the stripping of a lot of hook up wires. While these are readily available off-the-shelf, [Stuart] decided a better solution was in order.

The project starts with a set of standard hand-operated wire strippers. A lasercut acrylic frame is then built, with a series of motors and gears to handle the transport of the wire to be stripped and to open and close the jaws of the wire strippers. Wire is fed in, stripped, fed further, stripped again, and then finally cut. The process then begins anew.

The machine is quite pleasant to watch in action, with a series of motors and limit switches helping to control the mechanism. It’s a great way to populate kits that require plenty of hookup wire without having to resort to the more common pressed-on jumper terminals that dominate the post-Arduino era. For context’s sake, this build is from the distant past, circa 2009. Plans to recreate it are available on Thingiverse. Video after the break.

Given this is the future, perhaps you’d prefer your wires laser-stripped instead?

[Thanks to Nikolai for the tip!]

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Robotic Wood Shop Has Ambitions To Challenge IKEA

Many people got their start with 3D printing by downloading designs from Thingiverse, and some of these designs could be modified in the browser using the Thingiverse Customizer. The mechanism behind this powerful feature is OpenSCAD’s parametric design capability, which offers great flexibility but is still limited by 3D printer size. In the interest of going bigger, a team at MIT built a system to adopt parametric design idea to woodworking.

The “AutoSaw” has software and hardware components. The software side is built on web-based CAD software Onshape. First the expert user builds a flexible design with parameters that could be customized, followed by one or more end users who specify their own custom configuration.

Once the configuration is approved, the robots go to work. AutoSaw has two robotic woodworking systems: The simpler one is a Roomba mounted jigsaw to cut patterns out of flat sheets. The more complex system involves two robot arms on wheels (Kuka youBot) working with a chop saw to cut wood beams to length. These wood pieces are then assembled by the end-user using dowel pegs.

AutoSaw is a fun proof of concept and a glimpse at a potential future: One where a robotic wood shop is part of your local home improvement store’s lumber department. Ready to cut/drill/route pieces for you to take home and assemble.

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Adding Optics to a Consumer Thermal Camera

[David Prutchi] writes in to tell us about his recent experiments with building lenses for thermal imaging cameras, which to his knowledge is a first (at least as far as DIY hardware is concerned). With his custom designed and built optics, he’s demonstrated the ability to not only zoom in on distant targets, but get up close and personal with small objects. He’s working with the Seek RevealPro, but the concept should work on hardware from other manufacturers as well.

In his detailed whitepaper, [David] starts by describing the types of lenses that are appropriate for thermal imaging. Glass doesn’t transmit the wavelengths that thermal camera is looking for, so the lenses need to be made of either germanium or zinc selenide. These aren’t exactly the kind of thing you can pick up at the local camera shop, and even small lenses made of these materials can cost hundreds of dollars. He suggests keeping an eye out on eBay for surplus optics you could pull them out of to keep costs down.

Creating the macro adapter is easy enough, you simply put a convex lens in front of the thermal camera. But telephoto is a bit more involved, and the rest of the whitepaper details the math and construction techniques used to assemble it the optics. [David] gives a complete bill of materials and cost breakdown for his telephoto converter, but prepare for a bout of sticker shock: the total cost with all new hardware is nearly $500 USD. The majority of that is for the special lenses though, so if you can score some on the second-hand market it can drop the cost significantly.

We’ve seen an impressive array of thermal camera hacks and projects recently, no doubt due to the falling prices of consumer-level imaging hardware. Given their utility as a diagnostic tool, a thermal camera might be something worth adding to your bag of tricks.