An Armored Vehicle From Foam Core And Big Box Toys

March 19, 2020 by Tom Nardi 7 Comments

Over the last several months, [Eric Strebel] has been working on a concept for an electric-powered infantry combat vehicle. We don’t think he’s been contracted by any nation’s military to design this vehicle, but as a product designer we imagine he does this sort of thing to keep himself sharp. In any event, it’s been fun to watch from the sidelines.

In the latest installment in this series of videos, [Eric] turns his earlier concept art into a functional prototype; albeit at somewhat reduced scale. Still, building any kind of vehicle from the ground up is no easy feat and it’s fascinating to watch the process.

The futuristic faceted look of the vehicle’s armor plate makes for an exceptionally time-consuming build, as he has to cut and glue each piece of foam core into place. Some of the smaller pieces seem to have the tell-tale char marks from a trip through the laser cutter, but in the video after the break you can see that the larger panels are hand cut with a razor.

The plan was originally to just make a static mock-up of the vehicle, but thanks to a pair of remote controlled trucks that [Eric] found at this local Big Box retailer, this foam fighter ended up getting an upgrade. After liberating the motors and gearboxes from the two trucks, he 3D printed axle extensions to take into account the wider track of his vehicle, and built his “tub” around it. While the R/C gear is clearly on the low end of the spectrum, the overall effect looks great as the vehicle is bounding around the yard.

Readers of Hackaday will no doubt be well aware of [Eric Strebel] and his many talents. From 3D scanning via photogrammetry to embedding electronics into flexible molded parts, you’re sure to learn something new from following this prolific maker.

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Rubber Bands Can Secure Your Sanity

March 19, 2020 by Kristina Panos 4 Comments

One of the greatest joys of being a child was figuring out that rubber bands make awesome sounds when they are plucked, and that the sound is easily changed by stretching the band to different lengths. For those of us who need firsthand experience to truly understand how the world works, these types of self-discovery are a pretty great way to learn about physics.

If you’re looking to build a physical music lesson or musical physics lesson into your burgeoning home school curriculum, look no further than the junk drawer, the broom closet, and the 3D printer. [Ham-made] used to stretch his bands across an empty tissue box, but came up with a much more professional implementation based on a broom handle. Check out this fat sound!

You don’t even need to find a spare broom handle, because none of this is permanent — the headstock piece with the hooks is meant to slide up and down to create cool sounds, and the tailpiece threads on in place of the broom bristles. Inside the tailpiece is a piezo disk and a 1/4″ jack so you can plug it in to your amp stack and start an impromptu jazz group. Just keep it under 10 people, okay?

You’ll need to mic your chanteuse, so keep the physics fun going with this plastic cup microphone.

Baby Keyboard Is Really Three Boards

March 19, 2020 by Kristina Panos No comments

Just when we think we’ve peeped all the cool baby keebs out there, another think comes along. This bad boy built by [andyclymer] can be configured three different ways, depending on what kind of control you’re after.

As designed, the PCB can be used as a six-switch macro keyboard, or a rotary encoder with two switches, or a pair of rotary encoders. It’s meant to be controlled with Trinket M0, which means it can be programmed with Arduino or CircuitPython.

This could really only be cooler if the key switch PCB holes had sockets for hot-swapping the switches, because then you could use this thing as a functional switch tester. But hey, you can always add those yourself.

If you’re in the market for purpose-built add-on input device, but either don’t have the purpose nailed down just yet, or aren’t sure you want to design the thing yourself, this board would be a great place to start. Usually, all it takes is using someone else’s design to get used to using such a thing, at which point it’s natural to start thinking of ways to customize it. [andyclymer] is selling these boards over on Tindie, or you can roll your own from the repo.

Need just a few more inputs? We’ve got you covered.

Handwashing Timer Makes Sure The Suds Stay On Long Enough

March 19, 2020 by Dan Maloney 21 Comments

“Twinkle, Twinkle, Little Star”? How we wonder why you’d resort to singing a ditty to time your handwashing when you can use your social isolation time to build a touch-free electronic handwash timer that the kids — and you — might actually use.

Over the last few months, pretty much everyone on the planet has been thrust into strange, new, and oftentimes scary practices to limit the spread of the SARS-CoV-2virus and the disease it causes, COVID-19. Judging by the number of people we’ve seen leaving public restrooms without a visit to the washbasin before the outbreak began — and sadly all too often since — we collectively have a lot of work to do in tightening up our handwashing regimens. Time on target and plenty of friction are the keys to that, and [Denis Hennessy]’s “WashTimer” aims to at least help you out with the former. His build is as simple as can be: an Arduino driving an LED matrix when a proximity sensor fires. Wave your dirty paws in front of the unit as you start to scrub up, and the display goes through a nicely animated 20-second countdown, at which time it’s safe to rinse off.

[Denis] purposely made this design as simple and as customizable as possible. Perhaps you’ve got a Neopixel ring lying about rather than the LED matrix, or maybe an ultrasonic sensor would work better for you. Be creative and take this design where it needs to go to suit your needs. We can’t stress enough that handwashing is your number one defense; if you don’t need to moisturize your hands at least three times a day, you’re probably not washing often or long enough. And 20 seconds is way longer than you think it is without a prompt.

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A 555 And A Lighter Make High Voltage

March 19, 2020 by Al Williams 20 Comments

If you don’t have a ready source of high voltage, here’s an easy way to build one from the aptly-named [HVZapp]. The parts list is pretty simple to acquire, except for the transformer. For that, [HVZapp] raided a broken arc lighter. It took us a minute to realize that the MOSFETs are in parallel. The hand-drawn schematic shows a little “jump” from the drain lead to the source lead, but if you aren’t careful, it looks like the FETs are shorted out, which — of course — they aren’t.

The original arc lighter, of course, did a fine job of creating high voltage, although perhaps not as much as this circuit. Also, it would turn off every 10 seconds, which isn’t very useful if you want to use it as a power supply.

If you aren’t sure what to do with a high voltage, supply, there’s an associated quick and dirty Jacob’s Ladder in the video below. If you want your high voltage in a more natural way, consider harnessing lightning. There are many ways to generate high voltages.

The Corona Clock

March 19, 2020 by Elliot Williams 19 Comments

Schools are closed here in Germany until after Easter vacation, and that means that our almost-six-year-old son Max is staying at home with us. The good news is that my wife and I work from home anyway, so it’s not too stressful as long as he can look after himself for eight hours per day. The bad news is that there’s no way a kindergarten kid can take care of himself for such long stretches, and we don’t want to just park him in front of the boob tube. At least there’s two of us.

The new stay-at-home life has required some adjustment, but for at least the first five days (and counting) it’s working out pretty darn well. One trick: my wife came up with the idea of a visual schedule to help Max divide his day up into kindergarten-sized chunks, and then we added an LED strip behind it to turn it into a linear clock of sorts. And we did it with stuff we had lying around the house.

Granted, it’s not a super deep hacky-hack, and some of you out there could probably get it done with a handful of 555 timers. But it was quick, gets the job done, and heck, with NTP sync, it’s the most accurate kiddie clock in the world! So those of you out there who are stuck like we are, trying to balance childcare and working from home, here’s a quick project that can increase familial harmony while giving you an excuse to order more LED strips.

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Do You Smell What The Magic Chef Is Cookin’?

March 19, 2020 by Kristina Panos 6 Comments

Automata are already pretty cool, but the ones that can fool us are something extraordinary. The legendary [Greg Zumwalt] has recently turned his toy-making attentions toward illusory automata, and we think he’s off to a great start with his admirable appetizer, the Magic Chef.

The Chef aims to please, and as long as he has the power to do so, he’ll keep offering dishes from his six-item menu of hamburger, hot dog, pizza slice, BLT, sunny-side-up egg, and banded gelatinous chunk we can’t quite identify. Amazingly, this one-man restaurant does everything with a single 6VDC gear motor, some magnets, and 58 printed parts including gears, cams, and levers. The way the food carousel moves on a sort of magnetic slip ring system is the icing on the cake.

If you want to whip up a Magic Chef of your own, all the STL files are available for take-out from the Instructables page. Hungry for more details? go wash up and get situated after the break, ’cause we’re serving up a demo video with some close-up views of the inner workings. Oh, and here’s some automata-brewed coffee for dessert.

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