No lab in almost any discipline was complete in the 70s and 80s without an X-Y plotter. The height of data acquisition chic, these simple devices were connected to almost anything that produced an analog output worth saving. Digital data acquisition pushed these devices to the curb, but they’re easily found, cheap, and it’s worth a look under the hood to see what made these things tick.
The HP-7044A that [Kerry Wong] scored off eBay is in remarkably good shape four decades after leaving the factory. While the accessory pack that came with it shows its age with dried up pens and disintegrating foam, the plotter betrays itself only by the yellowish cast to its original beige case. Inside, the plotter looks pristine. Completely analog with the only chips being some op-amps in TO-5 cans, everything is in great shape, even the high-voltage power supply used to electrostatically hold the paper to the plotter’s bed. Anyone hoping for at least a re-capping will be disappointed; H-P built things to last back in the day.
[Kerry] puts the plotter through its paces by programming an Arduino to generate a Lorenz attractor, a set of differential equations with chaotic solutions that’s perfect for an X-Y plotter. The video below shows the mesmerizing butterfly taking shape. Given the plotter’s similarity to an oscilloscope, we wonder if some SDR-based Lissajous patterns might be a fun test as well, or how it would handle musical mushrooms.
It is easy to forget, but the Arduino does use C++. Typically, the C++ part is in the libraries and the framework and most people just tend to code their main programs using a C-style just using the library objects like C-language extensions. [Fredllll] recently created a template library to speed up Arduino I/O and he shared it on GitHub.
If you’ve ever done anything serious with the Arduino, you probably know that while digitalWrite is handy, it does a lot of work behind the scenes to make sure the pin is setup and this adds overhead to every call. [Fredllll’s] template versions can switch a pin’s state in two cycles. You can cut that in half if you don’t mind bothering the state of other pins on the same port.
If you want to get into electronics, it’s pretty straightforward: read up a little, buy a breadboard and some parts, and go to town. Getting into molecular biology as a hobby, however, presents some challenges. The knowledge is all out there, true, but finding the equipment can be a problem, and what’s out there tends to be fiendishly expensive.
So many would-be biohackers end up making their own equipment, like this DIY gel electrophoresis rig. Electrophoresis sorts macromolecules like DNA or proteins by size using an electric field. For DNA, a slab of agarose gel is immersed in a buffer solution and a current through the tank moves the DNA through the gel. The shorter the DNA fragment, the easier it can wiggle through the pores in the gel, and the faster it migrates down the gel. [abizar]’s first attempt at a DIY gel rig involved a lot of plastic cutting and solvent welding, so he simplified the process by using the little plastic drawers from an old parts cabinet. With nichrome and platinum wires for electrodes for the modified ATX power supply, it’s just the right size and shape for the gel, which is cast in a separate mold. The video below shows the whole build, and while [abizar] doesn’t offer much detail on recipes or techniques, there are plenty of videos online to guide you.
Hope springs eternal for Smell-O-Vision. [Niklas Roy] recently taught a workshop called Communication Devices at ÉCAL in Lausanne, Switzerland. Four of his Media & Interaction Design students built a scanner that detects colors and emits a corresponding scent.
The project consists of an Arduino connected to a color sensor as well as a SparkFun EasyDriver. The EasyDriver controls a stepper motor which rotates a disc of scent swatches so you sniff the swatch corresponding with the color. The students chose strawberry for red, and blue ended up being “ocean”-scented room spray.
With design students involved it’s no surprise the project looked good. Bouquet’s creators [Erika Marthins], [Arthur Moscatelli], [Pietro Alberti] and [Andrea Ramìrez Aburto] gave the device an intriguingly featureless look, and the “olfactory graphic design” posters they created to demonstrate it look great as well.
Electrospinning is the process of dispensing a polymer solution from a nozzle, then applying a very high voltage potential between the nozzle and a collector screen. The result is a very, very fine fiber that is stretched and elongated down to nanometers. Why would anyone want this? These fibers make great filters because of their large surface area. Electrospinning has been cited as an enabling technology for the future of textiles. The reality, though, is that no one really knows how electrospinning is going to become a standard industrial process because it’s so rare. Not many labs are researching electrospinning, to say nothing of industry.
[Douglas Miller] is building his own electrospinning machine. Except for the ominous warning signs on the 40-kilovolt power supply, there’s nothing in this machine that makes it look any different from a normal, homebrew 3D printer. There are stepper motors inside to raise and lower a carriage, a syringe, and a handy USB port. If you didn’t know any better, you could easily assume [Doug]’s OpenESpin is designed to print fidget spinners and tiny tugboats instead of films of carbon nanotubes and piezoelectric thermoplastics.
The DIY electrospinning machine is really what the Hackaday Prize is all about. It’s an enabling technology anyone can build for a few hundred dollars that also allows real science to happen. The films and blobs being formed in [Doug]’s electrospinning machine could easily find a home in a PhD candidate’s thesis or as a component in cutting edge research on everything from battery technology to the Internet of Underpants.
Poke around enough on AliExpress, Alibaba, and especially Taobao—the Chinese facing site that’s increasingly being used by Westerners to find hard to source parts—and you’ll come across some interesting things. The Long-CZ J8 is one of those, it’s 2.67 inch long and weighs just 0.63 ounces, and it’s built in the form factor of a Bluetooth headset.
A couple of months ago Cory Doctorow highlighted this tiny phone, he’d picked up on it because of the marketing. The lozenge-shaped phone was being explicitly marketed that it could “beat the boss”. The boss in question here being the B.O.S.S chair—a scanning technology that has been widely deployed across prisons in the U.K. in an attempt to put a halt to smuggling of mobile phones to inmates.
I wasn’t particularly interested in whether it could make it through a body scanner, or the built-in voice changer which was another clue as to the target market for the phone. However just the size of the thing was intriguing enough that I thought I’d pick one up and take a look inside. So I ordered one from Amazon.
It’s May, and you know what that means: we’re winding down from a worldwide celebration of the worker, pollen is everywhere, Hackaday readers in the southern hemisphere are somehow offended, and somewhere, someone is finishing up a remote-controlled snow blower build.
In this nine-part, two-hour-long video series, [Dave] covers the planning and fabrication of one of the most coveted of all cold weather yard instruments. It’s a remote-controlled snow blower. Just think: instead of bundling up to go blow the driveway off, [Dave] can get all the snow off his driveway from the comfort of his living room window. Sure, it may not sound like a big deal now that it’s Crocs & Socks weather, but this is going to be a great invention in seven or eight months.
This snow blower robot is built around two motors taken from an electric wheelchair. Most snowblowers already have tracks, so the ever-important traction for this build is already taken care of. A linear actuator takes care of the angle of the ‘scoop’, and a clever confabulation of bicycle sprockets, chain, and a motor allows the ‘chute’ of the snowblower to be pointed in any direction. The electronics are simple enough – a normal, off-the-shelf RC transmitter and receiver handles the wireless communication while an Arduino takes those signals and turns them into something the relays and motors understand.
This is one of the better build vlogs we’ve seen. There are nine parts to this build, we’ve included the final, wrapup video below.