The WIMP Is Dead, Long Live The Solar Axion!

For decades scientists have been building detectors deep underground to search for dark matter. Now one of these experiments, the XENON1T detector, has found an unexpected signal in their data. Although the signal does not stem from dark matter it may still revolutionize physics.

Since the 1980s the majority of scientists believe that the most likely explanation for the missing mass problem is some yet undiscovered Weakly Interacting Massive Particle (WIMP). They also figured that if you build a large and sensitive enough detector we should be able to catch these particles which are constantly streaming through Earth. So since the early 1990s, we have been putting detectors made from ultrapure materials in tunnels and mines where they are shielded from cosmic radiation and natural radioactivity.

Over the decades these detectors have increased their sensitivity by a factor of about 10 million due to ever more sophisticated techniques of shielding and discriminating against before mentioned backgrounds. So far they haven’t found dark matter, but that doesn’t mean the high-end sensing installations will go unused.

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The Cheap Way To Glitch An STM8 Microcontroller

Reverse engineering or modifying a device often requires you to access the firmware stored on a microcontroller. Since companies are usually not fond of people who try to peek into their proprietary data, most commercial devices are readout protected. [rumpeltux] ran into this problem when he tried to dump the firmware on an HC-12 wireless serial communication module for yet undisclosed reasons. Hacking into the device was a challenge that he gladly accepted and in the end, he succeeded by building a low-cost setup for voltage glitching.

Voltage glitching is a form of fault injection that has, e.g., been successfully used to hack the Playstation Vita. It involves the injection of voltage spikes on the power line in order to force the bootloader to skip security checks. The hard thing is trying to find the right shape of the waveform and the best way to inject the signal.

While there are already open-source boards for fault injection like ChipWhisperer, [rumpeltux] chose to build his own setup around an FPGA. By using a cheap EPM240 board, some MOSFET, and a USB-to-Serial converter, the total costs of the glitching setup were under 20 Euros. [rumpeltux] then recorded a larger number of voltage traces on the VCC pin around the reset phase and analyzed the differences. This helped him to pinpoint the best time for injecting the signal and refine the search space. After some unsuccessful attempts to glitch the VCC and GND pins, he got lucky when using one of the voltage regulator pins instead.

Be sure not to miss Samy Kamkar’s talk at Supercon 2019 if you want to know more about hardware attacks or how to eavesdrop on people using a bag of potato chips.

An Off-The-Grid Instant Messaging Plattform

Having an open-source communication device that is independent of any network and works without fees sounds like a hacker’s dream come true. Well, this is exactly what [bobricius]’ is aiming at with his Armawatch and Armachat devices.

Recently, [bobricius] built a LoRa based instant messaging device named Armachat. The gadget is controlled by a SAMD21 MCU with native USB and includes a QWERTY keyboard and an LCD display. Communication is based on an RFM95 LoRa transceiver which can reach a range of up to 2 km under ideal conditions. [bobricius] is a wiz when it comes to PCB design and one thing that makes his projects look so good is how he often uses PCBs as enclosures.

Armachat came in two form factors a large desktop and a smaller pocket version. The new Armawatch is another downsized version that perfectly fits on your arm by using a smaller display and keyboard. [bobricius] also did a lot of work on the firmware which now features a message delivery confirmation and the possibility to automatically resend undelivered messages. Future improvements will include message encryption, a store-and-forward function, and GPS position parsing. [bobricius] is also working on completing his portfolio of communicators with a credit-card-sized version.

LoRa is the go-to technology for off-the-grid communication devices and there are already other ongoing projects for using it to construct a mesh network.

Towards A 3D-Printed Neutrino Detector

Additive manufacturing techniques like fused deposition modeling, aka 3D printing, are often used for rapid prototyping. Another advantage is that it can create shapes that are too complex to be made with traditional manufacturing like CNC milling. Now, 3D printing has even found its way into particle physics as an international collaboration led by a group from CERN is developing a new plastic scintillator production technique that involves additive manufacturing.

A scintillator is a fluorescent material that can be used for particle detection through the flashes of light created by ionizing radiation. Plastic scintillators can be made by adding luminophores to a transparent polymer such as polystyrene and are usually produced by conventional techniques like injection molding.

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Smart Thermometer Can Tell Flu From Cold

Before the outbreak of coronavirus, the seasonal flu was one of the most dangerous infectious diseases, but a lot of people have trouble telling the difference between a flu and a cold by their symptoms alone. This gave [M. Bindhammer] the idea to design a smart thermometer that can distinguish between flu and cold.

Automated medical diagnostics is certainly an important technology of the future. [M. Bindhammer]’s project, named F°LUEX, is the second version of his iF°EVE thermometer. After taking the body temperature it asks the patient a set of questions about his symptoms and then calculates the probability of whether it is more likely to be a flu or a cold. [M. Bindhammer] uses a method commonly used in medical diagnostics based on Bayesian statistics which assigns a probability score to both hypotheses. It takes into account how often a certain symptom occurs when you have a common cold or flu as well as the overall probability of catching one or the other.

The hardware of the project is based on a custom PCB that includes a medical-grade MLX90614 infrared thermometer with an accuracy of ±0.2˚C around the human body temperature. The sensor is being read out by a Teensy 3.2 and information is displayed on a small OLED screen. Everything is housed in a 3D printed enclosure that received a nice finishing by painting with primer and acrylic spray paint. Unfortunately, [M. Bindhammer] project also got delayed by the corona crisis as his order for the temperature sensor got canceled due to the current high demand. But that does make us wonder how useful this could be to discriminate between cold, flu, and COVID-19.

An IR thermometer is something useful to have around not only for medical applications and can also be built without a custom PCB and minimal parts.

Hunting Neutrinos In The Antarctic

Neutrinos are some of the strangest particles we have encountered so far. About 100 billion of them are going through every square centimeter on Earth per second but their interaction rate is so low that they can easily zip through the entire planet. This is how they earned the popular name ‘ghost particle’. Neutrinos are part of many unsolved questions in physics. We still do not know their mass and they might even be there own anti-particles while their siblings could make up the dark matter in our Universe. In addition, they are valuable messengers from the most extreme astrophysical phenomena like supernovae, and supermassive black holes.

The neutrinos on earth have different origins: there are solar neutrinos produced in the fusion processes of our sun, atmospheric neutrinos produced by cosmic rays hitting our atmosphere, manmade reactor neutrinos created in the radioactive decays of nuclear reactors, geoneutrinos which stem from similar processes naturally occurring inside the earth, and astrophysical neutrinos produced outside of our solar system during supernovae and other extreme processes most of which are still unknown. Continue reading “Hunting Neutrinos In The Antarctic”

Fiber Optic Ceiling Pumps To The Beat

For years [Centas] dream was to take the stars to his home and build a fiber optic ceiling. Even though there are many fiber optic star ceiling kits commercially available, we are glad he decided to go full DIY on this project as the result is simply astonishing.

[Centas] chose to make a model of a section of the sky as it is visible from his home and generated a map of 1,200 stars with the planetarium software Celestia. The most time-consuming part of making a star ceiling is always poking lots of holes for the fibers. In [Cenas] case this turned out to be especially cumbersome as he decided to install the fibers after hanging the ceiling panel so he came up with a method to catch the fiber with a fishing pole after pushing it through from the bottom. The finished ceiling looks really great though with its rounded edges that contain RGB LED strips for side illumination. [Cenas] also painted the ceiling after installing the fibers so they are not visible when they are not lit but there is still enough light shining through the paint.

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