Trick Or Yeet Cannon Will Give Them Candy Shell Shock

One of our favorite things about Halloween is the sheer number of hacks that come out of it each year. This year, hacking is almost a requirement to keep things physically distanced, but that doesn’t mean we can’t have fun. You want fun? How about a candy cannon that launches sweet projectiles at trick-or-treaters from fifty feet?

[Paul McCabe]’s cannon uses a sprinkler valve and an air compressor to launch a pair of fun size candy bars, each encased in a film canister shell. Each trick-or-treater stomps a foot switch fifty feet away at the end of the driveway, and as long as someone is there holding down the primary ignition, the cannon will fire with a nice retort that sounds like a large wind instrument playing a D note.

We were sad to learn that the parachute idea didn’t shake out, but the glow sticks are a great addition for night time. Check out the demo after the break, which is followed by a build video and then some more launches for the fun of it.  Don’t have enough time to build a cannon of this caliber? You could put a spooky six-foot slide together pretty quickly.

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Cardboard Models Trace Design Process Of Vintage Tektronix Miniscopes

There aren’t many brands that inspire the kind of passion and fervency among its customers as Tektronix does. The venerable Oregon-based manufacturer of top-end test equipment has produced more collectible gear over the last 75 years than just about anyone else.

Over that time they have had plenty of innovations, and in the 1970s they started looking into miniaturizing their flagship oscilloscopes. The vintageTEK museum, run by current and former employees, has a review of the design process of the 200 series of portable oscilloscopes that’s really interesting. At a time when scopes were portable in the way a packed suitcase is portable, making a useful instrument in a pocketable form factor was quite a challenge — even for big pockets.

The article goes into great detail on the back-and-forth between the industrial designers, with their endless stream of models, and the engineers who would actually have to stuff a working scope into whatever case they came up with. The models from the museum’s collection are wonderful bits of history and show where the industrial designers really pushed for some innovative designs.

Some of the models are clearly derived from the design of the big bench scopes, but some have innovative flip-down covers and other interesting elements that never made it to production. Most of the models are cardboard, but some were made of aluminum in the machine shop and sport the familiar “Tek blue” livery. But the pièce de résistance of the collection is a working engineering model of what would become the 200-series of miniscopes, a handmade prototype with a tiny round CRT and crudely labeled controls.

The vintageTEK museum sounds like another bucket-list stop for computer and technology history buffs. Tek has been doing things their own way for a long time, and stopping by the museum is sure to be a treat.

Thanks to [Tanner Bass] for the tip.

Tracking Boats And Ships In Real Time At The Same Time

Software-defined radio came on the hacker scene in a big way less than a decade ago thanks to the discovery that a small USB-based TV tuner dongle could be used for receiving all kinds of radio transmissions. Two popular projects from that era are tracking nearby airplanes and boats in real time. Of course, these projects rely on different frequencies and protocols, but if you live in a major port city like [Ian] then his project that combines both into a single user interface might be of interest.

This project uses an RTL-SDR dongle for the marine traffic portion of the project, but steps up to a FlightAware Pro dongle for receiving telemetry from airplanes. Two separate antennas are needed for this, and all of the information is gathered and handled by a pair of Raspberry Pis. The Pis communicate with various marine and air traffic databases as well as handles the custom user interface that knits both sets of information together. This interface was custom-built from a previous project of his and was repurposed slightly to fit the needs of this one.

This is a great project that goes into a lot of interesting detail about how the web traffic moves and how the UI works, so even if you’re not into software-defined radio it might be worth a look. However, it’s also worth noting that it hasn’t been easier to set up a system like this thanks to the abundance and low price of RTL-SDR dongles and the software tools that make setting them up a breeze.

Digital Preservation For Old Batteries

The times they are a-changin’. It used to be that no household was complete without a drawer filled with an assortment of different sizes and types of batteries, but today more and more of our gadgets are using integrated rechargeable cells. Whether or not that’s necessarily an improvement is probably up for debate, but the fact of the matter is that some of these old batteries are becoming harder to find as time goes on.

Which is why [Stephen Arsenault] wants to preserve as many of them as possible. Not in some kind of physical battery museum (though that does sound like the sort of place we’d like to visit), but digitally in the form of 3D models and spec sheets. The idea being that if you find yourself in need of an oddball, say the PRAM battery for a Macintosh SE/30, you could devise your own stand-in with a printed shell.

The rather brilliantly named Battery Backups project currently takes the form of a Thingiverse Group, which allows other alkaline aficionados to submit their own digitized cells. The cells that [Stephen] has modeled so far include not only the STL files for 3D printing, but the CAD source files in several different flavors so you can import them into your tool of choice.

Like the efforts to digitally preserve vintage input devices, it’s not immediately clear how many others out there are willing to spend their afternoons modeling up antiquated batteries. But then again, we’ve long since learned not to underestimate the obscure interests of the hacker community.

A Linear Stencil Clock Built For Quiet Operation

We around the Hackaday shop never get tired of seeing new ways to mark the passage of time. Hackers come up with all manner of interesting timekeeping modalities using every imaginable material and method of moving the mechanism once per whatever minimum time unit the hacker chooses to mark.

But honestly, there are only so many ways to make a clock, and while we’re bound to see some repeats, it’s still nice to go over old ground with a fresh approach. Take this linear sliding stencil clock for instance. [Luuk Esselbrugge] has included some cool design elements that bear a closer look. The video below shows that the display is made up of four separate stepper motors, each driving a vertical stencil via a rack-and-pinion mechanism. There a simple microswitch for homing the display, and a Neopixel for lighting things up.

The video below shows that the stencils move very, very slowly; [Luuk] says that this is to keep the steppers as quiet as possible. Still, this means that some time changes take more than a minute to accomplish, which is a minor problem. The Neopixel also doesn’t quite light up just one digit, which should be a pretty easy fix for version 2. Still, even with these issues, we like the stately movements of this clock, and appreciate [Luuk]’s attempts to make it easier to live with.

Don’t let the number of clocks you see on these pages dissuade you from trying something new, or from putting your twist on an old design. Start with fridge magnets, an old oscilloscope, or even a bevy of steel balls, and let your imagination run wild. Just make sure to tell us all about it when you’re done.

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Pulse Oximetry Sensor Judges Your Coffee Roast

Breakout board for the MAX30101, which [Zach] used as the basis of his roast gauge. The sensor is at the top edge of the board.
Parts designed and marketed for a specific application can nevertheless still be useful in other ways, and whenever that happens, it’s probably the start of a pretty good hack. Using a sensor for something other than its intended purpose is exactly what [Zach Halvorson] did to make the Roast Vision device, which uses the MAX30101, a sealed optical sensor intended mainly for pulse oximetry and heart-rate monitoring.

[Zach] is instead using that sensor to measure the roast level of coffee beans, and assign a consistent number from 0 to 35 to represent everything from Very Dark to Very Light. Measuring a bean’s roast level is important to any roaster seeking accuracy and consistency, but when [Zach] found that commercial roast gauges could easily cost over a thousand dollars, he was sure he could do better.

[Zach] settled on using a Sparkfun MAX30101 breakout board to develop his device, and Sparkfun shared an informative blog post that demonstrates how making hardware and tools more accessible can help innovative ideas flourish. The Roast Vision device has a 3D printed enclosure, and a simple top-loading design with an integrated sample cup makes it easy to use. One simply puts about a teaspoon of finely-ground coffee into the sample cup, and the unit provides a measurement in a couple of seconds. Fortunately the sensor works just fine though an acrylic window which means the device can be sealed; a handy feature for a tool that will spend a lot of time around ground coffee.

The joys of fresh roasted coffee is something that is perfectly accessible to those making small batches at home. There are commercial options for small roasters of course, but should you wish to go the DIY route, check out our own Elliot Williams’ guide on making a low-cost DIY roaster.

Clacker Hacker: Popping A Cap In A Brother EP43 Thermal Typewriter

A few months ago, I fell down the internet rabbit hole known as Ted Munk’s typewriter site. I don’t remember if I just saw this Brother EP43 typewriter for sale and searched for information about them, or went looking for one after reading about them. Either way, the result is the same — I gained a typewriter.

Now I’m not really a typewriter collector or anything, and this is my first word processor typewriter. When it arrived from Goodwill, I anxiously popped four ‘C’ cells in and hoped for the best. It made a print head noise, so that was a good sign. But almost immediately after that, there was a BANG! and then a puff of smoke wafted out from the innards. My tiny typewriter was toast.

21st Century Typewriter

Speaking of toast, this typewriter is thermal, which is why it takes such awesome battery power. Thermal is probably the absolute best feature it could possibly have, because as long as there is electricity and thermal fax paper to be had on Earth, this typewriter can be used endlessly, no ribbon necessary. And that’s a good thing, considering that replacement ribbon cassettes are about $95 each.

There are a ton of other reasons that this typewriter is still awesome today. First off, the obvious: distraction-free typing. Like all word processors, you get a buffer of characters that can be corrected before they’re committed to paper.

It’s very small and lightweight compared to most typewriters and word processors. Really, it’s the pinnacle of print on demand. Seriously, the only thing smaller that qualifies is an embossing label maker or Braille writer.

As you can see by the demo sheet, there are a ton of word processing features that take the guesswork out of making documents look pretty. It does bold, underline, and right margin flush with just a few extra keystrokes. There’s even a four-banger calculator if your adding machine is too far out of reach!

Physically speaking, the whole thing is adorable, especially the little print head. And it has ISO enter, which is labeled RETURN. I keep meaning to cut some of my fax roll down into sheets, but once I made a paper dispenser with two 3D printed triangles and a dowel rod, I was far less motivated. Also, it’s really easy to tear the paper off by just tearing it against the clear plastic ruler guide.

The only real cons of this machine are that I can’t connect it to a computer, and I can’t connect a more ergonomic keyboard to her. I’m good for about a page, single-spaced, and then my wrists start complaining.

Back to the Smoke Monster

Note the ribbon cassette. Now it’s a souvenir on my bulletin board.
It just had to be the one cemented to the inductor that blew.

After I opened it up and surveyed the damage, I found that one of the big capacitors had been what blew. I decided to just order all new electrolytics for it to get ahead of future problems. This was especially wise considering how difficult this thing is to put it back together.  The plastic ribbon cables are quite fiddly.

In the end, I replaced all but two of the electrolytics. One of them I just couldn’t find a replacement for. The other I couldn’t replace because the one I ordered ended up having too big of a footprint. I was so focused on getting short-enough replacements for the big boys, that I screwed that one up completely.

After replacing the caps I got my Hello, World on. Now I type on it whenever I can, usually about once a day. Naturally, I think more fondly of it because I nursed it back to health. Here’s to another thirty or forty years of distraction-free clacking, thermal-paper supply willing!