Day: April 2, 2020

Star Trackers: Telling Up From Down In Any Space

April 2, 2020 by 28 Comments

Keeping track of position is crucial in a lot of situations. On Earth, it’s usually relatively straight-forward, with systems having been developed over the centuries that would allow one to get at least a rough fix on one’s position on this planet. But for a satellite out in space, however, it’s harder. How do they keep their communications dishes pointed towards Earth?

The stars are an obvious orientation point. The Attitude and Articulation Control Subsystem (AACS) on the Voyager 1 and 2 space probes has the non-enviable task of keeping the spacecraft’s communication dish aligned precisely with a communications dish back on Earth, which from deep space is an incomprehensibly tiny target.

Back on Earth, the star tracker concept has become quite popular among photographers who try to image the night skies. Even in your living room,  VR systems also rely on knowing the position of the user’s body and any peripherals in space. In this article we’ll take a look at the history and current applications of this type of position tracking. Continue reading “Star Trackers: Telling Up From Down In Any Space” →

Peel Apart Your ISP’s Router

April 2, 2020 by 35 Comments

Whether your home Internet connection comes by ADSL, fibre, cable, or even satellite, at some point in the chain between your ISP and your computer will be a router in your home. For some of us it’s a model we’ve bought ourselves and loaded up with a custom distro, but for the majority it’s a box supplied by our ISP and subject to their settings and restrictions. [Paddlesteamer] has just such a router, a Huawei model supplied by the Turkcell ISP, and decided to do a little snooping into its setup.

In a tale of three parts, we see the device unravel, from uncovering a shell to reverse engineering its update process, to delving in its firmware and finally removing all its restrictions entirely. It’s a fascinating process in which we learn a lot, such as the way a man-in-the-middle attack is performed on the router’s connection tot he ISP, or that it contains an authorised SSH key seemingly giving Huawei a back door into it. You may never do this with your ISP’s router, but it pays to be aware of what can be put in your home by them without your realising it.

The Golden Age of router hacking may be behind us as the likes of the Raspberry Pi have replaced surplus routers as a source of cheap Linux boards, but  as this shows us there’s still a need to dive inside a router from time to time. After all, locked-down routers are hardly a new phenomenon.

Via Hacker News.

Particle Sniffer For Pollution Point Sources

April 2, 2020 by 13 Comments

When measuring air quality, particulate matter is an important metric to watch. The PM2.5 rating refers to particulate matter that has a diameter of less than 2.5 micrometers. While it’s often measured by authorities on a city-wide basis, [rabbitcreek] wanted a way to track down point sources indoors.

The tool [rabbitcreek] built is in a similar form factor to a typical infrared workshop thermometer. Inside, it packs a Honeywell HPMA115S0-TIR laser particle sensor, hooked up to an ESP32 which runs the show. The sensor chosen makes things easy, with the device already set up with a blower and inlet and outlet ports for taking accurate readings.. Results are displayed on an SSD1306 OLED screen. It’s all wrapped up in a 3D printed case with a trigger grip, and a dog nose on the front which hints at the devices true purpose.

In testing, the device proves capable of detecting point sources of atmospheric particulates like flowers and a toaster. It’s something we’re sure would prove handy to those working in HVAC and environmental assessment industries. We’ve seen other rigs for monitoring particulates before, too. Video after the break.

Continue reading “Particle Sniffer For Pollution Point Sources” →