Remember those tiny little droids skittering around the pristine corridors of the Death Star in Star Wars? [heychaostheory] has put together something vaguely along the lines of those charming little mobile toasters. It’s an autonomous mouse droid with party mode!

The build is interesting in that it’s based on an off-the-shelf metal robot chassis—which provides mounting points for the gearmotors and wheels that make up the drivetrain. The mouse droid body sits atop this, being a 3D printed part that is afixed with heat set inserts and nylon standoffs. It’s 3D printed and expertly decorated with a fun vibe. Inside the body lives an Arduino Uno, hooked up to an L298 motor driver board and ultrasound sensors used for obstacle avoidance. It’s also got a smattering of LEDs to flash, because blinkenlights matter. The best bit, though, is the party mode button, which fires off music via a DFPlayer Mini module.

The mouse droid may not be as flashy and imposing as the Droideka or as mechanically impressive as BB-8, but that just makes it more accessible and fun to build. You can easily create one at full scale without breaking the bank. If you’re cooking up your own fun droids in the workshop, don’t hesitate to let us know. Video after the break.

There are plenty of ways to capture 3D images or simulations of such if you know what you’re doing with camera hardware and fancy mathematics. However, a little more unusual is the idea of capturing a 3D image while using no lens at all — and yet, [okooptics] has achieved just that!

The basic concept builds on an older project from [okooptics], wherein images were captured from a Raspberry Pi camera with no regular lens element installed. In its place was a thin layer of Scotch tape over the sensor, acting as a diffuser. With the right deconvolution math, it’s possible to actually recover a real image out of the blurry mess this setup initially captures. [okooptics] was then able to push this into three dimensions by weighting the point spread function used to deconvolute the image.

Adding directional bias to the process creates a similar effect to slightly shifting the cameras position, actually revealing a view from a slightly different angle of objects in front of the camera. [okooptics] does a great job of explaining the science behind how this is possible and the practical limitations of the technique, also referencing research papers that have explored these ideas in great depth.

It’s math heavy to extract 3D data from what otherwise looks like blurry nothingness, but it’s possible if you know what you’re doing. For a fuller understanding, it’s worth diving into [okooptics] earlier work in this realm, taking photos with Scotch tape in place of a lens.

Nifty little AMOLED screens are easy to get nowadays, and [Sophie D] demonstrates they are both thin and light enough to be worn with OpenChoker, a design for a choker necklace that was a hit at DEF CON.

The choker consists of an AMOLED touchscreen flanked by short RGB LED strips. Behind the display is the PCB which contains an RP2350 and micro SD card slot for external storage, and at the rear of the choker is an 18650 cell to power it all. The display plays an eye-catching animation that gets generated on the fly while the LEDs sparkle away.

[Sophie] shares a number of interesting takeaways from designing and building this device. One is that the bulk of the PCB design work was interfacing to the display, since no existing footprint or reference design could be found. So if you find yourself with a Hello Lighting HL020E21-02 2.14″ touchscreen display you’re hankering to use in your own project, do yourself a favor and check out [Sophie]’s board design instead of starting from scratch.

Battery life was more than enough for a device like this. A single 18650 cell powered the choker effortlessly for a 16-hour stretch and still the cell measured a robust 3.7 V. While a light-up choker used indoors isn’t a great candidate for wearable solar power, it’s encouraging that there’s no need for a tethered battery pack.

Another tip to consider relates to the screen’s touch sensitivity. In short, the capacitive touch screen responded perfectly when plugged into a development computer, but when mounted and isolated on the choker it responded so poorly as to be useless. It didn’t keep the rest of the choker from doing its job, but it might be worth keeping in mind as something to watch out for with a device like this.

There’s one final mystery [Sophie] ran into: with only one day to spare, glue used to affix some wires ended up melting away the wire insulation, revealing bare copper. We’re not sure what happened there, but if nothing else it’s a reminder that Murphy’s Law is always ready to strike when one is on a deadline.

Usually in Tech In Plain Sight, we talk about technology you probably see every day, even if you don’t notice it. But we hope you don’t get to see one of the latest crop of medical robots, such as the LUCAS chest compression system. If you watch the popular TV series “The Pitt”, though, you may have caught a glimpse of one of these medical marvels. They aren’t fiction. They are very real devices.

Calling them robots might be stretching the definition a little. They don’t roam the halls looking for patients. But once attached to someone in cardiac arrest, they can take over one of the most important — and physically demanding — parts of CPR: chest compressions.

Keep The Blood Moving

When someone’s heart stops pumping blood, time is critical. CPR doesn’t normally restart the heart on its own. Instead, chest compressions produce enough blood flow to keep oxygen reaching the brain and heart while rescuers work on the underlying problem and, when appropriate, use a defibrillator.

Doing that well is harder than it looks on television. Current American Heart Association guidelines call for adult chest compressions 100 to 120 times per minute, at least 5 cm deep but generally no deeper than 6 cm, while allowing the chest to recoil fully between compressions. Interruptions should be kept to a minimum.

That’s hard physical work. In fact, studies show compression depth begins to fall after only about 90 to 120 seconds, which is one reason CPR teams normally swap compressors every two minutes. But a robot doesn’t get tired.

Meet LUCAS

LUCAS stands for Lund University Cardiopulmonary Assist System, reflecting the device’s origins in Lund, Sweden. Early versions entered clinical use around 2002-2003 and were pneumatically powered. Later versions replaced the compressed-gas system with an electric motor and battery.

The current LUCAS 3 looks something like a small drill press straddling the patient as you can see in the video below. A backplate goes beneath the torso, and a frame locks onto it. An electrically driven piston presses a suction-cup-like pad against the sternum. Internally, the motor drives a belt and ball screw that moves the piston up and down.

Factory settings are around 102 compressions per minute and roughly 53 mm compression depth for a typical adult, although parameters can be configured.

Beyond tirelessness, another obvious advantage is that LUCAS doesn’t need hands. Medics can deal with ventilation, drugs, defibrillation, IV access, and the dozens of other things occurring during a cardiac arrest. More importantly, the device can keep compressing while a patient is being carried, wheeled through corridors, or transported in an ambulance — situations where doing good manual CPR is awkward and sometimes dangerous to the practitioner.

So Does It Save More People?

You might reasonably expect perfectly regular machine CPR to beat a tired human. Large randomized trials haven’t demonstrated that, however. The 4,471-patient PARAMEDIC trial found 30-day survival of 6.3% with LUCAS versus 6.8% with manual CPR, not a statistically significant difference. The 2,589-patient LINC trial similarly found essentially identical four-hour survival — 23.6% versus 23.7% — and no significant improvement in longer-term neurological outcomes.

That doesn’t make the machines useless. It says something slightly different: high-quality mechanical CPR hasn’t proven superior to high-quality manual CPR as a routine replacement. The International Liaison Committee on Resuscitation currently recommends against routine mechanical CPR, while specifically noting that it can be a reasonable alternative when sustained manual compressions are impractical or would endanger the practitioner.

One issue is setup. Installing the machine adds a time penalty: compressions must stop briefly while the backplate and mechanism are positioned. Good training is essential to keep that interruption short. Another problem is that some studies show potential links to higher rates of internal chest injuries, such as bleeding around the lungs. There have also been rare device malfunctions or power failures that can compromise care.

Not The Only Game In Town

LUCAS isn’t alone. ZOLL’s AutoPulse takes a very different mechanical approach. Instead of a piston pushing on one spot, a motor tightens a broad load-distributing band around the patient’s chest.

There’s also the German corpuls cpr, which returns to the piston idea but uses a cantilevered single-arm mechanism. That leaves much of the chest unobstructed and makes the system useful during procedures such as cardiac catheterization.

So perhaps these aren’t quite the autonomous robot doctors science fiction promised us. But when your heart has stopped, and a machine is tirelessly pumping your chest a hundred times a minute while the medical team works around it, you probably won’t complain. We hope you don’t have to find out.

We’ve seen DIY devices, though certifying medical devices for actual use isn’t for the faint of heart. Robots can also help train humans to do better CPR.

Featured image is a still from the instructional video “Physio-Control LUCAS 3 Chest Compression System – Hospital Use” by MFI Medical.

Drones have become a potent military threat, particularly on the small scale. Nimble multi-rotor drones are fast, difficult to spot, and can cause plenty of harm if allowed to go about their work unhindered. The first step to dealing with this issue is detection—a problem that [Agam Rossen] has put some work into.

The result is VolAnti—an open-source drone detector. This route was chosen as a reliable way to detect incoming multi-rotors, since spinning propellers tend to create a telltale sound that can be plucked from the noise quite specifically. In a world where fiber optic drones eschew RF emissions, it also proves particularly useful for early warning of such craft.

VolAnti relies on a small four-microphone array, with the I2S output of all four mics summed together. The output is then fed into a 2048-point FFT running every 32 ms on an ESP32-S3. A comb score is given to try and pick out different blade rates from 70 Hz to 2000 Hz. Multiple detection algorithms run in parallel, because [Agam] noted a problem—using an adaptive noise floor would miss drones that arrived in the area and hovered in place. With the noise not varying, it would get filtered out by the adaptive floor, so one algorithm in the four runs with no floor to catch drones that aren’t moving. Files are on GitHub for those curious to learn more.

We’ve featured other acoustic detection projects before, too. If you’re working on something similar, or conversely, you have the inside scoop on how to hide a drone’s noise signature, don’t hesitate to let us know on the tipsline.

E-ink is supposed to be the electronic version of dead-tree paper, but there’s one enormous difference: how you get your images and text onto it. For paper, you print on it. E-ink? Well, it depends on what it’s hooked up to. If it’s an ESP32C3-based Xteink X4 and X3, then you can just print to that, too, thanks to [Nishant Joshi]’s fork of the popular CrossPoint firmware.

The fork implements the Internet Printer Protocol, IPP, on the ESP32-C3. It makes loading documents a breeze: select the printer in your operating system, and press print. To the computer, the reader advertises itself as a printer that provides monochrome, single-sided output at 300 DPI on A5 paper, and accepts Apple raster and PWG raster formats. Of course these raster images are enormous compared to the paltry RAM available on the microcontroller, so pixels are received and written row-by-row — both to the screen directly, and to the SD card for later perusal. That makes a folder on the SD card the equivalent of a printer’s output tray.

This interface is amazing in its simplicity, and we’d love to see it in other E-ink devices. It reminds us somehow of AlphaSmart word processors — which are still relevant today in large part because their ‘file transfer’ mechanism is to pretend to be a USB keyboard and type the document onto your computer. As long as IPP is available, so too will you be able to get documents onto this e-reader.

Origami is a wonderful art form, but as a new project from the Shibaura Institute of Technology demonstrates, it can also have applications in the world of wearable tech.

The project involved creating paper-based sensors that could be worn on the body. These sensors were designed to be self-folding into helical forms, which would allow them to adapt neatly to the wearer over a wide range of body dimensions. This was achieved by using a standard inkjet printer to print patterns onto a flat piece of paper, with the printed patterns creating a self-folding behavior in the paper itself. Copper tape was then applied to the paper in order to act as an electrode for picking up triboelectric signals and measuring galvanic skin response. The idea is that these methods could be used to quickly and easily produce custom low-cost wearable sensors for a range of applications.

We’ve featured all kinds of interesting wearable hacks over the years, from power delivery via skin to shirts that will hide you from automated surveillance system. If you’re working on your own fancy projects that hang, clip, or dangle from the human body, don’t hesitate to let us know on the tipsline.