Non-Nefarious Raspberry Pi Only Looks Like a Hack

We’re going to warn you right up front that this is not a hack. Or at least that’s how it turned out after [LiveOverflow] did some digital forensics on a mysterious device found lurking in a college library. The path he took to come to the conclusion that nothing untoward was going on was interesting and informative, though, as is the ultimate purpose of the unknown artifacts.

As [LiveOverflow] tells us in the video below, he came upon a Reddit thread – of which we can now find no trace – describing a bunch of odd-looking devices stashed behind garbage cans, vending machines, and desks in a college library. [LiveOverflow] recognized the posted pictures as Raspberry Pi Zeroes with USB WiFi dongles attached; curiosity piqued, he reached out to the OP and offered to help solve the mystery.

The video below tells the tale of the forensic fun that ensued, including some questionable practices like sticking the device’s SD card into the finder’s PC. What looked very “hackerish” to the finder turned out to be quite innocuous after [LiveOverflow] went down a remote-diagnosis rabbit hole to discern the purpose of these devices. We won’t spoil the reveal, but suffice it to say they’re part of a pretty clever system with an entirely non-nefarious purpose.

We thought this was a fun infosec romp, and instructive on a couple of levels, not least of which is keeping in mind how “civilians” might see gear like this in the wild. Hardware and software that we deal with every day might look threatening to the general public. Maybe the university should spring for some labels describing the gear next time.

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Mechanisms: Lead Screws and Ball Screws

Translating rotary motion to linear motion is a basic part of mechatronic design. Take a look at the nearest 3D-printer or CNC router — at least the Cartesian variety — and you’ll see some mechanism that converts the rotation of the the motor shafts into the smooth linear motion needed for each axis.

Hobby-grade machines are as likely as not to use pulleys and timing belts to achieve this translation, and that generally meets the needs of the machine. But in some machines, the stretchiness of a belt won’t cut it, and the designer may turn to some variety of screw drive to do the job.

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Unique Flat-Screen Display Put to Use in CRT Game Boy

The cathode-ray tube ruled the display world from the earliest days of TV until only comparatively recently, when flat-screen technology began to take over. CRTs just kept getting bigger over that time until they reached a limit beyond which the tubes got just too bulky to be practical.

But there was action at the low end of the CRT market, too. Tiny CRTs popped up in all sorts of products, from camcorders to the famous Sony Watchman. One nifty CRT from this group, a flat(tish) tube from a video intercom system, ended up in [bitluni]’s lab, where he’s in the process of turning it into a retro Game Boy clone with a CRT display. The display, which once showed the video from a door-mounted camera, was a gift from a viewer. Date codes on the display show it’s a surprisingly recent device; were monochrome TFT displays that hard to come by in 2007? Regardless, it’s a neat design, with the electron gun shooting upward toward a curved phosphor screen. With a little Google-assisted reverse engineering, [Bitluni] was able to track done the video connections needed to use his retro game console, which uses an ESP32 that outputs composite video. He harvested the intercom speaker for game audio, added a temporary Nintendo gamepad, and soon he was playing Tetris in glorious monochrome on the flat screen.

The video below is only the first in a series where the prototype will be stuffed into one nice tidy package. It certainly still needs some tweaking, but it’s off to a great start. We can’t wait to see the finished product.

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Hacked Heating Instruments for the DIY Biology Lab

[Justin] from The Thought Emporium takes on a common molecular biology problem with these homebrew heating instruments for the DIY biology lab.

The action at the molecular biology bench boils down to a few simple tasks: suck stuff, spit stuff, cool stuff, and heat stuff. Pipettes take care of the sucking and spitting, while ice buckets and refrigerators do the cooling. The heating, however, can be problematic; vessels of various sizes need to be accommodated at different, carefully controlled temperatures. It’s not uncommon to see dozens of different incubators, heat blocks, heat plates, and even walk-in environmental chambers in the typical lab, all acquired and maintained at great cost. It’s enough to discourage any would-be biohacker from starting a lab.

[Justin] knew It doesn’t need to be that way, though. So he tackled two common devices:  the incubator and the heating block. The build used as many off-the-shelf components as possible, keeping costs down. The incubator is dead simple: an insulated plastic picnic cooler with a thermostatically controlled reptile heating pad. That proves to be more than serviceable up to 40°, at the high end of what most yeast and bacterial cultures require.

The heat block, used to heat small plastic reaction vessels called Eppendorf tubes, was a little more complicated to construct. Scrap heat sinks yielded aluminum stock, which despite going through a bit of a machinist’s nightmare on the drill press came out surprisingly nice. Heat for the block is provided by a commercial Peltier module and controller; it looks good up to 42°, a common temperature for heat-shocking yeast and tricking them into taking up foreign DNA.

We’re impressed with how cheaply [Justin] was able to throw together these instruments, and we’re looking forward to seeing how he utilizes them. He’s already biohacked himself, so seeing what happens to yeast and bacteria in his DIY lab should be interesting.

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Arduino Provides Hands-Free Focus for Digital Inspection Scope

With surface-mount technology pushing the size of components ever smaller, even the most eagle-eyed among us needs some kind of optical assistance to do PCB work. Lots of microscopes have digital cameras too, which can be a big help – unless the camera fights you.

Faced with a camera whose idea of autofocus targets on didn’t quite coincide with his, [Scott M. Baker] took matters into his own hands – foot, actually – by replacing mouse inputs to the camera with an outboard controller. His particular camera’s autofocus can be turned off, but only via mouse clicks on the camera’s GUI. That’s disruptive while soldering, so [Scott] used an Arduino Pro Micro and a small keypad to mimic the mouse movements needed to control the camera.

At the press of a key, the Arduino forces the mouse cursor up to the top left corner of the screen, pulls down the camera menu, and steps down the proper distance to toggle autofocus. The controller can also run the manual focus in and out or to take a screenshot. There’s even a footswitch that forces the camera to refocus if the field of view changes. It looks really handy, and as usual [Scott] provides a great walkthrough in the video below.

Like it or not, if shrinking technology doesn’t force you into the microscope market, entropy will. If you’re looking for a buyer’s guide to microscopes, you could do worse than [Shahriar]’s roundup of digital USB scopes. Or perhaps you’d prefer to dumpster dive for yours.

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Fail of the Week: Leaf Blowers Can’t Fly

Leaf blowers, the main instrument of the suburban Saturday symphony, are one of the most useful nuisances. It doesn’t take much work with a rake to convince even the most noise-averse homeowner to head to the Big Box Store to pick one up to speed lawn chores. Once you do buy one, and feel the thrust produced by these handheld banshees, you might wonder, If I let go of this thing, would it fly? 

[Peter Sripol] had that very thought and set about building a couple of leaf blower powered planes to answer the question. It’s probably not a spoiler alert to report that the answer is no, but the video below is a fun watch anyway. The surprising thing is just how close both planes came to succeeding. The first plane was a stripped-down Ryobi two-stroke leaf blower suspended from a giant wing and tail section that very nearly got off the ground. Version 1.1 gained a retractable electric boost propeller – strictly for take-offs – and lost a lot of excess weight. That plane practically leaped into the air, but alas, servo problems prevented [Peter] from shutting down the electric and flying on Ryobi alone. Even a servo fix couldn’t save the next flight, which cratered right after takeoff. A version 2.0, this time using a brutally modified electric leaf blower, was slightly more airworthy but augured in several times before becoming unflyable.

What can we learn from all this? Not much other than it would take a lot of effort to make a leaf blower fly. We appreciate all of [Peter]’s hard work here, but we think he’s better off concentrating on his beautiful homebrew ultralight instead.

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3D-Printer Extrudes Paper Pulp Instead of Plastic

We’ve seen all sorts of 3D-printers on these pages before. From the small to the large, Cartesians and deltas, and printers that can squeeze out plastic, metal, and even concrete. But this appears to be the first time we’ve ever featured a paper-pulp extruding 3D-printer.

It’s fair to ask why the world would need such a thing, and its creator, [Beer Holthuis], has an obvious answer: the world has a lot of waste paper. Like 80 kg per person per year. Thankfully at least some of that is recycled, but that still leaves a lot of raw material that [Beer] wanted to put to work. Build details on the printer are sparse, but from the photos and the video below it seems clear how it all went together. A simple X-Y-Z gantry moves a nozzle over the build platform. The nozzle, an order of magnitude or two larger than the nozzles most of us are used to, is connected to an extruder by a plastic hose. The extruder appears to be tube with a stepper-driven screw that lowers a ram down onto the pulp, squeezing it into the hose. [Beer] notes that the pulp is mixed with a bit of “natural binder” to allow the extruded pulp to keep its shape. We found the extrusion process to be just a wee bit repulsive to watch, but fascinating nonetheless, and the items he’s creating are certainly striking in appearance.

This may be the first pulp printer to grace our pages, but it’s not the first pulp hack we’ve featured. Pulp turns out to be a great material to keep your neighbors happy and even makes a dandy fuel.

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