A Raspberry Pi-based COVID Green Pass validator verifies a QR code on a phone.

COVID Green Pass Validator With Raspberry Pi

September 25, 2021 by Kristina Panos No comments

It seems like every nation is dealing with the plague a little differently. In June, the EU instated a COVID Green Pass which comes in the form of a paper or digital QR code. It was designed to grease the wheels of travel throughout Europe and allow access to nursing homes. As of early August, the Green Pass is now required of those 12 and older in Italy to gain access to bars and restaurants, museums, theaters, etc. — anywhere people gather in sizeable groups. The Green Pass shows that you’ve either been vaccinated, have had COVID and recovered, or you have tested negative, and there are different half-lives for each condition: nine months for vaccinated, six for recovered, and just forty-eight hours for a negative test.

[Luca Dentella] has built a Green Pass validator using a Raspberry Pi and a Raspi camera. Actual validation must be done through the official app, so this project is merely for educational purposes. Here’s how it works: the user data including their status and the date/time of pass issuance are encoded into a JSON file, then into CBOR, then it is digitally signed for authenticity. After that, the information is zipped up into a base-45 string, which gets represented as a QR code on your phone. Fortunately, [Luca] found the Minister of Health’s GitHub, which does the hard work of re-inflating the JSON object.

[Luca]’s Pi camera reads in the QR and does complete validation using two apps — a camera client written in Python that finds QRs and sends them to the validation server, written in Node.js. The validation server does formal verification including verifying the signature and the business rules (e.g. has it been more than 48 hours since Karen tested negative?) Fail any of these and the red LED lights up; pass them all and you get the green light. Demo video is after the break.

Are you Canadian? Then check this out, eh?

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Mechanisms Behind Vaccine Side-Effects: The Science That Causes That Sore Arm

September 21, 2021 by Maya Posch 85 Comments

After receiving a vaccination shot, it’s likely that we’ll feel some side-effects. These can range from merely a sore arm to swollen lymph nodes and even a fever. Which side-effects to expect depend on the exact vaccine, with each type and variant coming with its own list of common side-effects. Each person’s immune system will also react differently, which makes it hard to say exactly what one can expect after receiving the vaccination.

What we can do is look closer at the underlying mechanisms that cause these side-effects, to try and understand why they occur and how to best deal with them. Most relevant here for the initial response is the body’s innate immune system, with dendritic cells generally being among the first to come into contact with the vaccine and to present the antigen to the body’s adaptive immune system.

Key to the redness, swelling, and fever are substances produced by the body which include various cytokines as well as prostaglandin, producing the symptoms seen with inflammation and injury.

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Hacking When It Counts: Surgery Fit To Save A Future King

September 20, 2021 by Dan Maloney 43 Comments

When we picture the Medieval world, it conjures up images of darkness, privations, and sickness the likes of which are hard to imagine from our sanitized point of view. The 1400s, and indeed the entirety of history prior to the introduction of antibiotics in the 1940s, was a time when the merest scratch acquired in the business of everyday life could lead to an infection ending in a slow, painful death. Add in the challenges of war, where violent men wielding sharp things on a filthy field of combat, and it’s a wonder people survived at all.

But then as now, some people are luckier than others, and surviving what even today would likely be a fatal injury was not unknown, as one sixteen-year-old boy in 1403 would discover. It didn’t hurt that he was the son of the king of England, and when he earned an arrow in his face in combat, every effort would be made to save the prince and heir to the throne. It also helped that he had the good fortune to have a surgeon with the imagination to solve the problem, and the skill to build a tool to help.

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a very slapdash x-ray machine on a table

Building An X-Ray Machine

September 9, 2021 by Matthew Carlson 57 Comments

While we typically encourage hackers to make their own tools or machines when practical, x-ray machines don’t usually make that list. Despite the risk of radiation, [William Osman] has done just that and built a homemade x-ray machine. After receiving an eye-watering medical bill, [William] resolves to make his own x-ray machine in the hopes of avoiding future bills. Thanks to his insurance, the total owed was smaller but still ridiculous to those who live in single-payer health care countries, but it got William thinking. What if he could make an x-ray machine to do cheap x-rays?

Armed with a cheap high voltage DC power supply he acquired from an online auction house, he started to power up his x-ray vacuum tube. A smaller power supply energizes the cathode and forms an electron beam. Then the high voltage (30-150kv) is applied as a tube voltage, accelerating the electrons into x-rays. Safety measures are taken somewhat haphazardly with Geiger counters and lead sheets. With a finger bone cast in ballistic shell [William] made his first x-ray with a long exposure on a DSLR. The next items to go in the x-ray “chamber” were a phone and a hand. The results were actually pretty decent and you can clearly see the bones.

We’ve seen homemade X-Ray machines here at Hackaday before, but not one that is constructed perhaps so haphazardly — his approach makes this obvious: don’t try this at home. Video after the break.

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Dyson Award Goes To Emergency Medical Device For Treating Stab Wounds

August 29, 2021 by Al Williams 68 Comments

[Joseph Bentley] must be one of those people who sees opportunity in problems. He had several friends who were victims of knife attacks, so he developed REACT, a device that would allow police or other first responders to quickly help victims of stab wounds. The project won the Dyson award and you can see the video about it, below.

The device has two parts: a medical-grade silicone sleeve and a handheld actuator. The sleeve actually inserts into the stab wound and the actuator pressurizes the sleeve based on the location of the wound. The actuator has a user interface to allow the operator to select the area of the body affected.

We don’t know much about emergency medicine, but apparently, the current method is to apply pressure externally and this doesn’t do much for internal bleeding. The sleeve solves that and [Bentley] thinks the device can save many lives if brought to market. Of course, getting a medical device actually on the market is a long road fraught with regulatory peril. We hope the Dyson award will help [Bentley] get the product in the hands of people who can use it to good purpose.

We are very interested in replacing damaged body parts, but saving people from losing body parts or life is good, too. Sometimes, just calling for help is worthwhile.

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DIY Machine Enables PEMF Therapy On A Budget

August 29, 2021 by Tom Nardi 48 Comments

We’re certainly not qualified to say whether or not pulsed electromagnetic field (PEMF) therapy will actually reduce your stress or improve your circulation, but there seems to be enough legitimate research going on out there that it might be worth a shot. After all, unless you’ve got a pacemaker or other medical implant, it seems pretty unlikely a magnetic field is going to make anything worse. Unfortunately commercial PEMF machines can cost thousands of dollars, making it a fairly expensive gamble.

But what if you could build one for as little as $10 USD? That’s the idea behind the simple DIY PEMF machine [mircemk] has been working on, and judging by its ability to launch bits of metal in the video below, we’re pretty confident it’s indeed producing a fairly powerful electromagnetic field. Even if it doesn’t cure what ails you, it should make an interesting conversation piece around the hackerspace.

While the outside of the machine might look a bit imposing, the internals really are exceptionally straightforward. There’s an old laptop power supply providing 19 VDC, a dual-MOSFET board, a potentiometer, and a simple signal generator. The pulses from the signal generator trip the MOSFET, which in turn dumps the output of the laptop power supply into a user-wound coil. [mircemk] has a 17 cm (6.7 inch) open air version wrapped with 200 turns of copper wire used for treating wide areas, and an 8 cm (3 inch) diameter version with 300 windings for when you need more targeted energy.

Some skepticism is always in order with these sort of medicinal claims, but commercial PEMF machines do get prescribed to users to help promote bone growth and healing, so the concept itself is perhaps not as outlandish as it might seem.

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Universal Bio-Electrical Signal Amplifier Makes Reading Body Signals Easy

August 26, 2021 by Robin Kearey 18 Comments

The electrical signals emitted by the human body tell us a lot about what’s going on inside. But getting those signals inside your microcontroller is not straightforward: the voltages are too small for most ADCs, and the ever-present 50 or 60 Hz mains frequency makes it hard to discern subtle changes. Over at Upside Down Labs, [Deepak Kathri] developed a universal biosensor interface called the BioAmp EXG Pill to make all this a lot easier.

Its name refers to the fact that it can be used for several different bio-electrical sensing applications: ECG, EMG, EOG and EEG, which deal with signals coming from the heart, muscles, eyes and brain, respectively. To enable such flexibility, the board has connectors for two or three electrodes, as well as solder pads to mount resistors and capacitors to adjust the gain and bandwidth. An instrumentation amplifier increases the strength of the desired signal while rejecting noise and interference.

The form factor allows easy connection to electrodes on one side and a data acquisition system on the other. Measuring just 25.4 mm long and 10 mm wide, it should be easy to integrate into any type of biosensing gizmo you can come up with. [Deepak] has made several demo setups, showing him using the Pill with an Arduino to measure his heart rate, detect eye blinks, and even control a robot arm using his own arm muscles!

The EXG Pill is an evolution of an earlier EMG-only project. We’ve seen several great ECG and EEG projects before, but is the first time we’ve seen one amplifier that can do them all.