Hacking A Jack-in-the-Box To Be Extra Surprising

July 20, 2022 by 13 Comments

A Jack-In-The-Box is scary enough the first time. However, if you’ve seen the clown pop out before, it fails to have the same impact. [Franklinstein] decided that swapping out the clown for an alternative payload would deliver the fright he was after.

Inside the toy, an Arduino Nano runs the show. It’s paired with an airhorn, installed in a special frame along with an RC servo. When the time is right, the RC servo presses up against the airhorn, firing off an almighty noise. There’s also a confetti blaster, built with a small chamber full of compressed air. When a solenoid is released, the compressed air rushes out through a funnel full of confetti, spraying it into the room.

When the crank on the toy is turned, the typical song plays. When the lid of the box opens, it releases a switch, and the Arduino fires off the confetti and airhorn. It’s shocking enough for [Franklinstein] himself, and even more surprising for those expecting the toy’s typical bouncing clown instead.

We’d love to see an even more obnoxious version that doesn’t turn the airhorn off for at least a full minute. We’ve seen them employed in some great Halloween hacks before, too. Video after the break.

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3D Printed Skate Trucks Do Surprisingly Okay

July 20, 2022 by 18 Comments

If you can buy something off the shelf, there’s a good chance that someone has tried to 3D print their own version. [Daniel Norée] did just that with skateboard trucks, whipping up a design of his own.

The main body of the trucks is 3D-printed, as is the hanger. A 195 mm M8 threaded rod is then used through the center of the trucks in order to provide an axle for fitting the wheels and bearings themselves. He 3D-printed the parts using a carbon-fiber reinforced nylon with the slicer set up to maximize strength. In testing, they rolled around the neighbourhood just fine.

[Mayer Makes] found the design online, and 3D printed some using his own transparent high-impact resin, making a cool set of clear-ish trucks. It’s a tough material, which we’ve featured on this site before.

Those trucks ended up in the hands of [Braille Skateboarding], who put them through their paces. The trucks are loose, but take a good beating around the park. Eventually one of the trucks succumbs after landing many kickfilps and ollies on the concrete.

Other great skate hacks include casting your own wheels in a 3D-printed mold. Video after the break.

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Long-Range Thermocouple Sensor Sips Battery Power

July 20, 2022 by 4 Comments

Sometimes you need to know the temperature of something from a ways away. That might be a smoker, a barbecue, or even a rabbit hutch. This project from [Discreet Mayor] might just be what you’re looking for.

[Discreet Mayor] remotely keeps an eye on the meat, but doesn’t blab about it.
It consists of a MAX31855 thermocouple amplifier, designed for working with commonly-available K-type thermocouples. This is hooked up to a Texas Instruments CC1312 microcontroller, which sends the thermal measurements out over the 802.15.4 protocol, the same which underlies technologies like Zigbee and Thread. It’s able to send radio messages over long distances without using a lot of power, allowing the project to run off a CR2023 coin cell battery. Combined with firmware that sleeps the system when it’s not taking measurements, [Discreet Mayor] expects the project to run up to several years on a single battery.

The messages are picked up and logged in a Grafana setup, where they can readily be graphed. For extra utility, any temperatures outside a preset range will trigger a smartphone alert via IFTTT.

Keeping a close eye on temperatures is a key to making good food with a smoker, so this project should serve [Discreet Mayor] well. For anyone else looking to monitor temperatures remotely with a minimum of fuss, it should also do well!

Cut Just About Anything With This Combination Lathe And Wire EDM

July 20, 2022 by 18 Comments

They say that if you have a lathe, you have every other machine tool too. To some degree, that’s true — you can make almost anything on a lathe, including another lathe, and even parts best made on other machine tools can usually be made on a lathe in a pinch. But after seeing this lathe attachment for a DIY electric discharge machining tool, we might be inclined to see the EDM as the one machine tool to rule them all.

Now, we’ll admit that the job [BAXEDM] built this tool for might be a little contrived. He wanted to make some custom hex inserts for his Swiss Army knife, which seem like they’d have been pretty easy to make from hex bar stock in a conventional lathe. Then again, hardened steel is the kind of material that wire EDM was made for, and there seem to be many use cases for an attachment that can spin a workpiece against an EDM cutting wire.

That was really the trick of this build — spinning a part underwater. To accomplish this, [BAXEDM] built a platform to carry a bearing block that supports a standard ER-25 collet, with a bracket that holds a stepper clear of the water in the EDM cutting tank. There are plenty of 3D printed insulators too, to keep most of the attachment electrically isolated from the EDM current, plus exotic parts like ceramic bearings that won’t corrode under water. There were a ton of other considerations, too; [BAXEDM] goes through the long iterative design process in the video below, as well as taking his new tool for a literal spin starting at about the 27:00 mark.

If you’re intrigued by what EDM can accomplish — and who wouldn’t be? — but you need more background on the process, we’ve got you covered.

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Transparent Cylinder Shows You What You Otto Know About 4 Cycle Engines

July 20, 2022 by 15 Comments

When we think of a typical four stroke internal combustion engine, we think of metal. And for any type of longevity or performance, that’s certainly the right choice. But [Integza] wanted to see what happens inside a 4 stroke engine, and it wasn’t enough to see it from a transparent cylinder head. No, he wanted to see it in the cylinder itself. Thanks to advances in material sciences, he got his wish as seen in the video below the break.

While researching possible transparent materials to use as a cylinder on his model engine, he learned about resin polishing. Combining his newly learned resin polishing knowledge with his knowledge of 3D printing, [Integza] printed a new cylinder and polished the resin until it was transparent. The engine ran, but misfired terribly.

The experiment progressed into trying different fuels and learning the differences between them, as well as uncovering a new-to-him mystery: Why was the engine misfiring, and why did the different fuels act so dramatically different? Indeed, more learning and more experimenting is needed. But if you want to see the great sight of watching combustion take place in slo-mo, you have to check out the video below.

3D printing has come a long way in a short time, and may even hold the key to practical scramjets for hypersonic aircraft.

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Ask Hackaday: Resin Printer Build Plates

July 20, 2022 by 29 Comments

The early days of FDM 3D printing were wild and wooly. Getting plastic to stick to your build plate was a challenge. Blue tape and hairspray-coated glass were kings for a long time. Over time, better coatings have appeared and many people use spring steel covered in some kind of PEI. There seem to be fewer choices when it comes to resin printers, though. We recently had a chance to try three different build surfaces on two different printers: a Nova3D Bene4 and an Anycubic Photon M3. We learned a lot.

Resin Printing Review

If you haven’t figuratively dipped your toe into resin yet — which would literally be quite messy — the printers are simple enough. There is a tank or vat of liquid resin with a clear film on the bottom. The vat rests on an LCD screen and there is a UV source beneath that.

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The Casio Smartwatch You Never Had

July 20, 2022 by 26 Comments

In a way, you have to feel a bit sorry for the engineers at Casio. They can produce the most advanced digital watches ever to grace the wrist, but their work will forever be associated with one of their more lowly creations. The Casio F91 is the archetypal digital watch — it’s affordable, it’s been in production since the Ark, it does the job so well that it’s become a design classic, and it remains a very tough act to follow.

If it has a flaw though, it’s that the functions of a watch from 1989 are very basic. Wouldn’t it be nice if a Casio F91 could be a modern smartwatch! Well thanks to [Pegor] it can, with a complete re-engineering of the classic watch’s internals. Now the simple classic timepiece is fully up-to-date!

All the Casio internals are removed, and a new movement holder supports a fresh PCB with an OLED display mounted via a flexible sub-PCB. The brains comes courtesy of a Texas Instruments CC2640 BLE microcontroller. This gives it a 15-day battery life, which is nothing like what the original watch would have but compares favorably to smartwatches. He admits that the software needs some work, but with hardware this well-executed we hope that others can contribute some improvements.

This is probably the most impressive F91 hack we’ve seen, but it’s by no means the first revamped Casio we’ve shown you.