Every Boy Scout or Girl Guide probably had the experience of building a simple solar oven: an insulated box, some aluminum foil, and plastic wrap, and voila! On warm, sunny, summer days, you can bake. On cloudy days, well, you need another plan. The redoubtable [Kris De Decker] and [Marie Verdeil] provide one, with this solar-electric oven over on LowTechMagazine.
Now, you might be wondering: what’s special here? Can’t I just plug a full electric range-oven into the inverter hooked to my Powerwall? Well, yes, Moneybags, you could — if you had a large enough solar setup to offset the storage and inverter losses, that is. But if you only have a few panels, you need to make every watt count. Indeed, this build was inspired by [Kris]’ earlier attempt to power his apartment with solar panels on his balcony. His electric oven is one of the things that stymied him at that time. (Not because cooking took too much energy, but because it took too much power for his tiny battery to supply at once.)
After powering the camera with a power-over-Ethernet (PoE) adapter [Matt] sets about monitoring network activity with Wireshark. The first data comes from DNS for the host devaccess.easy4ipcloud.com, which whois reports is operated by Alibaba Cloud LLC in California. This is a Chinese owned company with servers in the United States.
[Matt] covers some basics of TLS and how it works. He then goes on to explain how a Man in the Middle (MITM) attack works at a high level. To setup a MITM attack against the camera [Matt] sets up some port redirections using iptables for ports 443, 15301, 8683, 9898, and 12337 which his Wireshark analysis indicates were being used. His MITM attack works, which means the device is not properly verifying its certificate signing chain.
[Matt] goes on to reverse engineer the custom UDP protocol used for transmitting video data. He uses a vibe-coded Python program along with ffmpeg for that and manages to reconstruct a few frames of video taken from the UDP packet capture.
We think it would be safe to say that [Matt] did indeed find a few security problems with the camera as-is, but we don’t think that’s the point of the ban. The real problem is that there is auto-update facilities for the device firmware which means that in future malicious software could be uploaded by the manufacturer in the form of a firmware update. So even if this device was secure against MITM attacks and didn’t send unencrypted video data over UDP you would still have the problem of the firmware update if there is no trust.
As any generation of people get older, they tend to look back fondly on their formative years when there was less responsibility and more wonder. Even if things have objectively improved, we often have a fondness for the past. Such is the case for cable television, where even though ads were everywhere and nothing was on-demand, we can see that something was lost from this era in the modern streaming ecosystem. [Ricardo] brought back the good parts of this golden era of cable TV with this small channel surfing television.
The project attempts to keep the good parts of this era while discarding things we certainly don’t miss. The ability to channel surf is still here, with a rotary encoder standing in for an antique television channel selector knob, but dealing with any telecommunications company is out, including those of the Internet variety. Instead it is a fully offline machine with the user able to curate their own channels and programming with a Flask application, and [Ricardo]’s includes his own collection of commercials from Argentina.
The hardware itself is fairly straightforward as well, with a Raspberry Pi doing the heavy lifting, paired with a small screen and enclosed in a retro-themed television case. It’s a clever throwback to a time where we might not know what we wanted to see but there was always something on. Builds like this are gaining popularity right now as well, and we’ve even seen them recreate the cable company’s preview channel as well.
The spectrum of laser technologies available to hackers has gradually widened from basic gas lasers through CO2 tubes, diode lasers, and now fiber lasers. One of the newer entries is the MOPA laser, which combines a laser diode with a fiber-based light amplifier. The diode’s pulse length and repetition rate are easy to control, while the fiber amplifier gives it enough power to do interesting things – including, as [Ben Krasnow] found, etch hologram-like diffraction gratings onto stainless steel.
Stainless steel works because it forms a thin oxide layer when heated, with a thickness determined by the temperature it reaches. The oxide layer creates thin-film interference with incoming light, letting the laser mark parts of a steel sheet with different colors by varying the intensity of heating. [Ben] wrote a script to etch color images onto steel using this method, and noticed in one experiment that one area seemed to produce diffraction patterns. More experimentation revealed that the laser could consistently make diffraction gratings out of parallel patterns of oxide lines. Surprisingly, the oxide layer seemed to grow mostly down into the metal, instead of up from the surface.
The pitch of the grating is perpendicular to the direction of the etched lines, and varying the line spacing changes the angle of diffraction, which should in theory be enough control to print a hologram with the laser. [Ben]’s first experiment in this general direction was to create a script that turned black-and-white photographs into shimmering matrices of diffraction-grating pixels, in which each pixel’s grating orientation was determined by its brightness. To add a parallax depth effect, [Ben] spread out images into a gradient in a diffraction grating, so that it produced different images at different angles. The images were somewhat limited by the minimum size required for the grating pixels, but the effect was quite noticeable.
When you think of a radio telescope, you usually think of a giant dish antenna pointing skyward. But [vhuvanmakes] built Wavy-Scope, a handheld radio telescope that can find the Sun and the Moon, among other things.
The build is relatively straightforward, using a commercial LNB to detect signals in the 10-12 GHz range. The detector is a simple satellite finder, although you could also connect it to a software-defined radio, if you wanted something more sophisticated.
The f-number of a lens indicates how well it will perform in low-light. To calculate the f-number you divide the focal length by the diameter of the aperture. A common f-number is f/1.4 which is generally considered “fast”.
We are told the fastest commercial lens ever used had f/0.7 and was used by Stanley Kubrick to shoot the film Barry Lyndon which was recorded only with candle light.
A microscope objective is a crucial lens that gathers and magnifies light to form an image. It plays a key role in determining the quality and clarity of the final magnified image produced by a microscope.
Switching power supplies are familiar to Hackaday readers, whether they have a fairly conventional transformer, are a buck, a boost, or a flyback design. There’s nearly always an inductor involved, whose rapid change in magnetic flux is harnessed to do voltage magic. [Craig D] has made a switching voltage booster that doesn’t use an inductor, instead it’s using a length of conductor, and no, it’s not using the inductance of that conductor as a store of magnetic flux.
Instead it’s making clever use of reflected short pulses in a transmission line for its operation. Electronics students learn all about this in an experiment in which they fire pulses down a length of coax cable and observe their reflections on an oscilloscope, and his circuit is very similar but with careful selection of pulse timing. The idea is that instead of reflected pulses canceling out, they arrive back at the start of the conductor just in time to meet a pulse transition. This causes them to add rather than subtract, and the resulting higher voltage pulse sets off down the conductor again to repeat the process. We can understand the description, but this is evidently one to sit down at the bench and experiment with to fully get to grips with.
