Kritik sah

It used to be a rite of passage to build some sort of AM radio receiver. Many people started with a crystal radio, of course, but you’d graduate to maybe a TRF or superhet design. FM radio projects were not as common, because demodulating an FM signal was harder, as was making things work in the 100 MHz range. These days, though, you can get everything on a chip like the TEA5767, and [turtushig22-blip] has an open design that uses that device on a breakout board, a display, a knob, and an external amplifier. An ESP-32 pulls it together. You can see two videos about the project below. Unlike older FM radio designs, the TEA5767 doesn’t require any adjustments. RF goes in, and stereo audio goes out. You can control the device through I2C or a 3-wire serial interface. Software-wise, you send a five-byte control word and the chip sends back five status bytes. You don’t set the frequency directly, but provide a PLL divisor. For example, with a 32 kHz reference crystal, s...

In this age of neural net “AI”, even the most skeptical of Butlerians have to agree that these machine learning models can be very, very good at pattern recognition if nothing else. NASA is on the same page, and to take advantage of that pattern recognition, they’ve built a machine learning module called COFFIES, which stands for Consequence Of Fields and Flows in the Interior and Exterior of the Sun , because at NASA everything is an acronym, or at least a backronym. Like most such names, this one is at least vaguely descriptive: the model is trying to predict what’s going on in the material flows and magnetic fields deep within our local star, and using those inferences is able to predict active regions– that’s sunspots to us chickens — up to 12 hours before they visibly form. The measurements used here are indirect —  we can’t chart the magnetohydrodynamic snarls deep inside a star directly, but we can measure the magnetic fiel...

Sometimes claimed to give you wings, energy drinks can, at the very least, be used to make rockets fly. This is what [Nate Scovill] did in a recent video , where cans of the sugary stuff are processed to give a rocket its proverbial wings. The basic concept is so-called rocket candy , which uses the fact that sugar is a pretty decent fuel type that — when combined with an oxidizer like potassium nitrate — can be turned into solid rocket fuel. Naturally it’d be easiest to start off with a pure source of sucrose or sorbitol for the sugar, but what if you only have access to cans of sugary soda? Removing the moisture from the energy drink was the obvious first step, as water and rocket fuel aren’t a great mix. Adding and mixing potassium nitrate to the resulting thick syrup created the fuel-oxidizer mixture, also known as rocket fuel. This did take a detour involving removing the carbonation using a vacuum chamber, as CO 2 and fire do not really like each other e...

Steam power is a staple of the steampunk aesthetic, thermodynamics, and a checkpoint for the budding mechanical engineer studying heat cycles. But because food is largely made of water, steam is also common in the culinary arts. So it’s no surprise that when thermodynamics is applied to cooking, exciting things can happen.  This particular example of steam-powered culinary happenings is inspired by industrial potato-peeling machines. By adding high-pressure, high-temperature steam to a pressure vessel with potatoes inside, heat can transfer more easily to the inside of the potatoes. Because the pressure is so high, however, the water in the skin won’t boil. This is fundamentally the same concept as a pressure cooker. However, what’s different is that instead of a pressure cooker’s slow release, these industrial peeling machines rely on explosive decompression, flash boiling the water underneath the potato’s skin. This rapidly expanding steam rips away the ...

It’s a sci-fi trope that you can ‘scan for life signs’ and detect if there are humans — or suspiciously human-shaped aliens — present, but in real life it’s harder than that. [The Masked Bear]’s wifisense-pi project isn’t really scanning for signs of life, either, unless you happen to consider breathing a sign of life. Even then, it’s not detecting breathing per se, but the subtle motion that goes with it: it’s a very sensitive motion detector that relies on the fact that we fleshy bags of goo disturb WiFi signals with our presence, and motion alters those disturbances. We’d probably waste a lot of time watching the signal graphs on the WifiSense-Pi dashboard. The device uses an ESP32-S3 to measure the radio channel 100 times per second, while a Raspberry Pi 4 provides the signal processing muscle. It can detect the slightest motions, and even determine the presence of a perfectly still human by their breathing, though...

Remember Animusic? They were these incredible animated music videos with original tunes being played by computer-generated robots. Well, the MegCell Pulse might be the coolest robots-playing-music thing we’ve seen since Animusic . Built by [Bruce] over six years’ time, this futuristic wonder features two robots working in concert to play acoustic guitar, just like a pair of human hands would. You just feed them digital tablature, and off go the fraternal twins, with one doing the fretting, and the other doing the plucking via six individual plectrum. It’s digital music producing analog sound from a physical instrument. How does MegCell Pulse work? It’s essentially a system of gears, magnetic actuators, and arms, contained in a 3D-printed structure. The only real limitations are that it can’t traverse the entire fretboard, nor can it slide between frets. That said, you can absolutely buy one for your own guitar via [Bruce]’s modestly-goaled Kickstar...