Plus Size Watch with a Pair of Tiny Nixies

When you stuff a pair of Nixie tubes into a wristwatch the resulting timepiece looks a little like Flavor Flav’s necklace. Whether that’s a good thing or not depends on your taste and if you’re comfortable with the idea of wearing 200 volts on your wrist, of course.

As a build, though, [prototype_mechanic]’s watch is worth looking into. Sadly, details are sparse due to a computer issue that ate the original drawings and schematics, but we can glean a little from the Instructables post. The case is machined out of solid aluminum and sports a quartz glass crystal. The pair of IN-16 tubes lives behind a bezel with RGB LEDs lighting the well. There’s a 400mAh LiPo battery on board, and an accelerometer to turn the display on with a flick of the wrist.

It may be a bit impractical for daily use, but it’s a nicely crafted timepiece with a steampunk flair. Indeed, [prototype_mechanic] shows off a few other leather and Nixie pieces with four tubes that certainly capture the feel of the steampunk genre. For one with a little more hacker appeal, check out this Nixie watch with a 3D-printed case.

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New Lathe Day is Best Day

As [Quinn Dunki] rightly points out, modern industrial civilization was probably conceived on the bed of a lathe. Turning is an essential step in building every machine tool, including lathes, and [Quinn] decided it was time to invite one into her shop. But she discovered a dearth of information to guide the lathe newbie through that first purchase, and thus was born the first installment in her series on choosing and using a new lathe.

As for the specifics of the purchase, [Quinn]’s article goes into some depth on the “old US iron” versus “new Asian manufacture” conundrum. Most of us would love an old South Bend or Cincinnati lathe, but it may raise practical questions about space planning, electrical requirements, and how much work is needed to get the old timer working again. In the end, [Quinn] took the path of least resistance and ordered a new lathe of Chinese heritage. She goes into some detail as to what led to that decision, which should help other first-timers too, and provides a complete account of everything from uncrating to first chips.

Nothing beats the advice of a grizzled vet, but there’s a lot to be learned from someone who’s only a few steps ahead of her intended audience. And once she’s got the lathe squared away, we trust she’ll find our tips for buying a mill helpful getting that next big shipment delivered.

“All the best things in life arrive on a pallet.” Have truer words ever been spoken? Sure, when the UPS truck pulls up with your latest Amazon or eBay treasure, it can be exciting. But a lift-gate truck rolling up to the curb? That’s a good day.

Recapture Radio’s Roots with an Updated Regenerative Receiver

Crystal radios used to be the “gateway drug” into hobby electronics. Trouble was, there’s only so much one can hope to accomplish with a wire-wrapped oatmeal carton, a safety-pin, and a razor blade. Adding a few components and exploring the regenerative circuit can prove to be a little more engaging, and that’s where this simple breadboard regen radio comes in.

Sometimes it’s the simple concepts that can capture the imagination, and revisiting the classics is a great way to do it. Basically a reiteration of [Armstrong]’s original 1912 regenerative design, [VonAcht] uses silicon where glass was used, but the principle is the same. A little of the amplified RF signal is fed back into the tuned circuit through an additional coil on the ferrite rod that acts as the receiver’s antenna. Positive feedback amplifies the RF even more, a germanium diode envelope detector demodulates the signal, and the audio is passed to a simple op amp stage for driving a headphone.

Amenable to solderless breadboarding, or even literal breadboard construction using dead bug or Manhattan wiring, the circuit invites experimentation and looks like fun to fiddle with. And getting a handle on analog and RF concepts is always a treat.

[via r/electronics]

Lean Thinking Helps STEM Kids Build a Tiny Windfarm

When we see a new build by [Gord] from Gord’s Garage, we never know what to expect. He seems to be pretty skilled at whatever he puts his hand to, with a great design sense and impeccable craftsmanship. You might expect him to tone it down a little for a STEM-outreach wind turbine project then, but when you get a chance to impress 28 fifth and sixth graders, you might as well go for it.

98j6zpStarting with an idea from his daughter’s teacher for wind turbines each kid could make, [Gord] applied a little lean methodology so the kids would be able to complete the build in the allotted time. The design is simple – a couple of old CDs holding vertical sections of PVC tubing to catch the breeze and spin neodymium magnets over four flat coils of magnet wire. It’s enough to light a single LED and perhaps a kid’s imagination.

As simple as the turbine is, the process of building it needed to be stripped of as much unnecessary work as possible, and [Gord] really shines here. He built jigs and fixtures galore, pre-built some assemblies, and set up well-organized workstations for each step of the build. Everything was clearly labeled, adult volunteers were trained using the video after the break, and a good time was had by all.

Sometimes the hack isn’t in the product but in the process, and [Gord] managed to hack a success out a potential disaster of disappointed kids. If getting a taste of [Gord]’s style makes you want to see more, check out his guitar fretting jig or his brake rotor mancave clock.

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A No-Solder, Scrap-Bin Geiger Counter for $15

Scenario: your little three-hour boat tour runs into a storm, and you’re shipwrecked on a tropic island paradise. You’re pretty sure your new home was once a nuclear test site, but you have no way to check. Only your scrap bin, camera bag, and hot glue gun survived the wreck. Can you put together a Geiger-Müller counter from scrap and save the day?

Probably not, unless your scrap bin is unusually well stocked and contains a surplus Russian SI-3BG miniature Geiger tube, the heart of [GH]’s desert island build. These tubes need around 400 volts across them for incident beta particles or gamma rays to start the ionization avalanche that lets it produce an output pulse. [GH]’s build uses the flash power supply of a disposable 35mm camera to generate the high voltage needed, but you could try using a CCFL inverter, say. The output of the tube tickles the base of a small signal transistor and makes a click in an earbud for every pulse detected.

You’ll no doubt notice the gallons of hot glue, alligator clips, and electrical tape used in the build, apparently in lieu of soldering. While we doubt the long-term robustness of this technique, far be it from us to cast stones – [GH] shows us what you can accomplish even when you find yourself without the most basic of tools.

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Forrest Mims, Radio Shack, and the Notebooks that Launched a Thousand Careers

There was a time when Radio Shack offered an incredible variety of supplies for the electronics hobbyist. In the back of each store, past the displays of Realistic 8-track players, Minimus-7 speakers, Patrolman scanners, and just beyond the battery bin where you could cash in your “Battery of the Month Club” card for a fresh, free 9-volt battery, lay the holy of holies — the parts. Perfboard panels on hinges held pegs with cards of resistors for 49 cents, blister packs of 2N2222 transistors and electrolytic capacitors, and everything else you needed to get your project going. It was a treasure trove to a budding hardware hobbyist.

But over on the side, invariably near the parts, was a rack of books for sale, mostly under the Archer brand. 12-year old me only had Christmas and birthday money to spend, and what I could beg from my parents, so I tended to buy books — I figured I needed to learn before I started blowing money on parts. And like many of that vintage, one of the first books I picked up was the Engineer’s Notebook by Forrest M. Mims III.

Wish I could find my original copy from 1979. This one is on Amazon.
Wish I could find my original copy from 1979. I just bought this one from Amazon.

Many years rolled by, and my trusty and shop-worn first edition of Mims’ book, with my marginal notes and more than one soldering iron burn scarring its pulp pages, has long since gone missing. I learned so much from that book, and as I used it to plan my Next Big Project I’d often wonder how the book came about. Those of you that have seen the book and any of its sequels, like the Mini-notebook Series, will no doubt remember the style of the book. Printed on subdued graph paper with simple line drawings and schematics, the accompanying text did not appear to be typeset, but rather hand lettered. Each page was a work of technical beauty that served as an inspiration as I filled my own graph-paper notebooks with page after page of circuits I would find neither the time nor money to build.

I always wondered about those books and how they came about. It was a pretty astute marketing decision by Radio Shack to publish them and feature them so prominently near the parts — sort of makes the string of poor business decisions that led to the greatly diminished “RadioShack” stores of today all the more puzzling. Luckily, Forrest Mims recently did an AMA on reddit, and he answered a lot of questions regarding how these books came about. The full AMA is worth a read, but here’s the short story of those classics of pulp non-fiction.

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3D-Printed Strain Wave Gear Needs Your Help

In most mechanical systems, metal gears that bend are a bad thing. But not so for strain wave gearing, which is designed to take advantage of a metal gear flexing to achieve an action much like planetary gears. The fun isn’t limited to metal anymore, though, if you 3D print a strain wave gear like this.

Strain-wave gearing is nothing new – it was invented in 1957 and has traveled to the moon on the lunar rover. And you may recall [Kristine Panos]’ recent article on a LEGO strain wave gear, which makes it easy to visualize how they work. She also has a great description of how the flex spline, wave generator, and circular spline interact, so we’ll spare those details here. [Simon Merret]’s interpretation of the strain wave gear is very simple and similar to other 3D-printed versions, except that he uses an inside-out timing belt as the flex spline. The wave generator is just an arm with a roller bearing at each end, and despite needing a few tweaks the gear does an admirable job.

Simon is reaching out for help in getting this gear ready for use where the industrial versions see frequent application – the first and second degrees of freedom of robotic arms. If you’ve got any ideas, head over to his project page on Hackaday.io and pitch in.

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