2D-Scanner Records Surfboard Profiles For Posterity

October 6, 2019 by Dan Maloney 5 Comments

[Ryan Schenk] had a problem: he built the perfect surfboard. Normally that wouldn’t present a problem, but in this case, it did because [Ryan] had no idea how he carved the gentle curves on the bottom of the board. So he built this homebrew 2D-scanner to make the job of replicating his hand-carved board a bit easier.

Dubbed the Scanbot 69420 – interpretation of the number is left as an exercise for the reader, my dude – the scanner is pretty simple. It’s just an old mouse carrying a digital dial indicator from Harbor Freight. The mouse was gutted, with even the original ball replaced by an RC plane wheel. The optical encoder and buttons were hooked to an Arduino, as was the serial output of the dial indicator. The Arduino consolidates the data from both sensors and sends a stream of X- and Z-axis coordinates up the USB cable as the rig slides across the board on a straightedge. On the PC side, a Node.js program turns the raw data into a vector drawing that represents the profile of the board at that point. Curves are captured at various points along the length of the board, resulting in a series of curves that can be used to replicate the board.

Yes, this could have been done with a straightedge, a ruler, and a pencil and paper – or perhaps with a hacked set of calipers – but that wouldn’t be nearly as much fun. And we can certainly see applications for this far beyond the surfboard shop.

DIY Clapper Lets You Pick Your Components

October 6, 2019 by Al Williams 4 Comments

One thing that always means the end of the year is close is the reappearance of TV ads for “The Clapper.” After all, who needs home automation when you can clap on and clap off? While we’re partial to our usual home automation solutions, [Utsource123] shows us that building a clapper can be a fun and easy project using several similar circuits. One with a few transistors and another one with a 555 because, after all, what can’t a 555 do?

Of course, these circuits usually have a microphone. We were trying to think of how you could make a sound-sensitive element out of common parts. After all, you don’t care about the fidelity of the microphone pickup, just that it hears a loud noise. The circuits are about what you’d expect. The transistor version uses one to amplify the microphone and another to switch on the LED. You’d need a bit more to trigger a relay. The 555 uses an even simpler preamp transistor as a trigger.

While we aren’t bowled over with the idea of a clapper, we imagine these circuits aren’t far removed from the ones you buy in stores. For about $16 you also get enough switching to handle a simple AC load, though. Maybe Alexa and Google should allow making clapping a wake up word?

This is sure simpler than the last clapper clone we saw. Then there’s the deluxe DIY version.

Upgrades Give Crazy Cart XL A Few More X’s

October 6, 2019 by Kristina Panos 4 Comments

Why should kids have all the newfangled fun? They shouldn’t! Quarter-life crises are on the rise, and those who can are spoiling their inner child with adult-sized Heelys and electric Mario Karts that can drift. [austiwawa] finally got his hands on a used Crazy Cart XL, and while it’s incredibly fun, the puny 500W motor doesn’t quite satisfy his need for speed. A 3x power upgrade should do the trick.

The new 1600W motor is considerably bigger, so [austiwawa] had to grind off part of the front fork to make it fit. He designed a replacement motor support plate and had it cut from quarter-inch steel. Of course, you can’t just drop in a crazy new motor like that and go — you need a battery and controller to match. A couple of attempts and a new spot welder later, [austiwawa] built a 48V battery pack out of 18650s. The cart actually weighs less now, which should make the ride extra insane. Put a helmet on FFS and drift past the break to the build video and demo. Then watch him tear up the mean ~~streets~~ parking lots of Canada and take the kart off some sweet jumps.

We love a good fun-mobile around here, be it scratch-built or hacked OEM. This wasn’t even [austiwawa]’s first rodeo — check out his water-cooled electric drift trike.

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This Lightning Detector Is Remarkably Sensitive

October 3, 2019 by Lewin Day 16 Comments

Lightning strikes are quite high energy events, and release plenty of radio frequency energy when they go off in the atmosphere. This makes them easy to detect, and the magnitude of the energy release means it can be done at impressive range. [Jay] decided to build a device of his very own, and was impressed at its detection performance.

The device is a simple but effective design. An antenna is used to capture RF signals, and these are then amplified through a single transistor stage. This is connected to a basic transistor flasher circuit, which is biased to only flash when tipped over the edge by an incoming signal. After building the circuit, [Jay] noticed that the device wasn’t just picking up signals from lightning, but also those from many other smaller discharges. The device was able to detect a shock from wearing socks on a wood floor, as well as discharges from a Van de Graff generator and even just from getting out of a chair!

Lightning detectors have been around for a long time now; we’ve seen others grace these pages before. Video after the break.

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Weather Alert Lamp Keeps An Eye On What’s Brewing

October 2, 2019 by Lewin Day 2 Comments

Whether you’re getting ready for work in the morning, or heading out on a camping trip in the woods, it’s nice to know what to expect when the weather rolls over the horizon. To keep abreast of things, [natethecoder] built a lamp system to stay across weather alerts.

A Raspberry Pi 3 acts as the heart of the system, with Node Red responsible for running the show. Querying the web every 5 minutes for updated weather data, it keeps track of weather alerts, as well as incoming snowfall. For a basic weather watch, a yellow lamp is lit, while there’s a red lamp for more serious warnings. A Christmas decoration serves as the indicator for snow. The lamps are all controlled by mains-rated solid state relays, making it easy to swap out the lamps for other devices if so desired down the track. There’s also a lamp test subroutine that fires on startup to ensure everything is working correctly.

It’s a handy way to get your weather info at a glance, and would prove useful to anyone living in a storm-prone area. For something more portable, consider this umbrella that tells you the weather.

The Clickspring Playing Card Press Is A Work Of Art

September 30, 2019 by Dan Maloney 31 Comments

We have no idea what a playing card press is, nor do we care. All we know is that after watching [Chris] from Clickspring make his playing card press, we want it.

Digging a little deeper, [Chris] offered to make this card press for [Chris Ramsay], a magician who specializes in cardistry, or the art of illusions with cards. The feel of playing cards is crucial to performing with them, and a card press keeps a deck of cards in shape. Not a commonly available device, [Clickspring Chris] designed one in an elaborate style that brought in elements from [Chris Ramsay]’s logo.

Like all Clickspring videos, this one is a joy to watch, but in a departure, there’s no narration — just 30 minutes of precision machining and metal finishing. [Chris] has gotten into metal engraving in a big way, and used his skills to add details to everything from the stylized acorn at the top to the intricate press plate, all of which was done freehand. And those snakes! Made from brass rod and bent into shape by hand, they wrap around the side supports to form [Chris Ramsay]’s logo. All the brass ended up gold plated, while all the screws ended up with a heat-blued finish. Settle in and enjoy the video below.

It’s been a while since the Clickspring skeleton clock was finished, in which time [Chris] has been working on a reproduction of the Antikythera mechanism. His video output slowed considerably, though, when he made a new finding about the mechanism, an observation worthy of writing up as a scholarly paper. We can’t begrudge him the time needed to pursue that, and we’re glad he found time for this project too.

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The Price Of Domestic Just In Time Manufacturing

September 29, 2019 by Kerry Scharfglass 37 Comments

Hardware is hard, manufacturing only happens in China, accurate pricing is a dark art. Facts which are Known To Be True. And all things which can be hard to conquer as an independent hardware company, especially if you want to subvert the tropes. You may have heard of [Spencer Wright] via his superb mailing list The Prepared, but he has also been selling an unusual FM radio as Centerline Labs for a few years. Two years ago they relaunched their product, and last year the price was bumped up by a third. Why? Well, the answer involves more than just a hand wave about tariffs.

The Public Radio is a single-station FM radio in a mason jar. It’s a seemingly simple single purpose hardware product. No big mechanical assemblies, no complex packaging, not even any tangential accessories to include. In some sense it’s an archetypically atomic hardware product. So what changed? A normal product is manufactured in bulk, tested and packaged, then stored in a warehouse ready to ship. But TPR is factory programmed to a specific radio station, so unless Centerline wanted one SKU for each possible radio station (there are 300) this doesn’t work. The solution was domestic (US) just in time manufacturing. When a customer hits the buy button, a unit is programmed, tested, packed, and shipped.

As with any business, there is a lot more to things than that! The post gives the reader a fascinating look at all the math related to Centerline Labs’ pricing and expenses; in other words, what makes the business tick (or not) including discussion of the pricing tradeoffs between manufacturing different components in Asia. I won’t spoil the logical path that led to the pricing change, go check out the post for more detail on every part.

We love hearing about the cottage hardware world. Got any stories? Drop them in the comments!