Pinning Tails On Satellites To Help Prevent Space Junk

Low Earth orbit was already relatively crowded when only the big players were launching satellites, but as access to space has gotten cheaper, more and more pieces of hardware have started whizzing around overhead. SpaceX alone has launched nearly 1,800 individual satellites as part of its Starlink network since 2019, and could loft as many as 40,000 more in the coming decades. They aren’t alone, either. While their ambitions might not be nearly as grand, companies such as Amazon and Samsung have announced plans to create satellite “mega-constellations” of their own in the near future.

At least on paper, there’s plenty of room for everyone. But what about when things go wrong? Should a satellite fail and become unresponsive, it’s no longer able to maneuver its way out of close calls with other objects in orbit. This is an especially troubling scenario as not everything in orbit around the Earth has the ability to move itself in the first place. Should two of these uncontrollable objects find themselves on a collision course, there’s nothing we can do on the ground but watch and hope for the best. The resulting hypervelocity impact can send shrapnel and debris flying for hundreds or even thousands of kilometers in all three dimensions, creating an extremely hazardous situation for other vehicles.

One way to mitigate the problem is to design satellites in such a way that they will quickly reenter the Earth’s atmosphere and burn up at the end of their mission. Ideally, the deorbit procedure could even activate automatically if the vehicle became unresponsive or suffered some serious malfunction. Naturally, to foster as wide adoption as possible, such a system would have to be cheap, lightweight, simple to integrate into arbitrary spacecraft designs, and as reliable as possible. A tall order, to be sure.

But perhaps not an impossible one. Boeing subsidiary Millennium Space Systems recently announced it had successfully deployed a promising deorbiting device developed by Tethers Unlimited. Known as the Terminator Tape, the compact unit is designed to rapidly slow down an orbiting satellite by increasing the amount of drag it experiences in the wispy upper atmosphere.

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A Nokia 5110 playing a game

Firmware Modding Your Vintage Nokia Handset

These days we’re spoiled for choice when it comes to smartphone software, especially games. Official repositories for the leading handsets feature hundreds of thousands of games, and sideloading adds infinite possibilities. If you were lucky enough to be sporting a Nokia handset in the late 1990s, you probably had all of three games to choose from (and only one that was actually fun). [Janus Cycle] explores the steps needed to firmware mod your vintage Nokia phone, and how to expand on that paltry games library.

Enthusiasts have been modding their Nokia handsets since the 2000s, and the tools required now are the same as they were then. The Nokia 5110 and 6110 (as featured in the video below) use a proprietary cable and connector for communicating with PCs and other devices. Nokia’s official serial cable already opens up many possibilities for handset tinkering, including access to RAM and toggling Monitor Mode. This cable interfaces solely with the phone’s fast FBUS protocol, however firmware flashing takes place using the slower MBUS protocol over a single wire bi-directional pin.

The handset expects both serial ports to be available during firmware flashing. [Janus Cycle] demonstrates how to build a custom harness that connects both serial ports to a PC parallel port. At this point the flashing process is relatively straightforward, especially if you have an appropriately vintage computer to run the old flashing software.

Nokia owners may fondly remember changing the network name on the home screen to all sorts of inappropriate graphics, yet far more was possible with the right technology and know-how. It’s interesting to think about what may have been if softmodding was more widespread during the reign of the Nokia 5110 and its peers.

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Trigger assembly for PS5 controller in palm of hand

How The PS5’s Genuinely Clever Adaptive Triggers Work

Sony’s Playstation 5 console and its DualSense controllers aren’t exactly new, but the triggers of the controllers have a genuinely interesting design that is worth examining. The analog triggers on the PS5 controllers are generally described as having “variable resistance”, but it turns out that’s not the whole story. Not only is the trigger capable of variable resistance when being pressed, but it can also push back in variable ways and with varying amounts of force. How it works is pretty clever.

Trigger assembly being moved in palm of handThe feedback for the trigger assembly is handled by a lever, a geared wheel, and a worm gear on an electric motor. Under normal circumstances, nothing interferes with the trigger at all and it works like a normal analog trigger. But when the motor moves the lever into place, trigger movement now has to overcome the added interference with a mechanical disadvantage. The amount of resistance felt can be increased a surprising amount by having the motor actively apply additional force to counter the trigger’s movement.

That’s not all, either. The motor can also actively move the lever into (or out of) position, which means that pulling the trigger not only has the ability to feel smooth, mushy, or stiff in different places, but it can also actively push back. This feedback can be introduced (or removed) at any arbitrary point along the trigger’s range of motion. A trigger pull can therefore feel like it has a sharp breakpoint, a rough travel, a hard stop, an active recoil, or any combination of those at any time.

It’s a little hard to describe, but you can get a better idea of it all works in practice by watching part of this teardown by [TronicsFix] (video cued to about 9:17 where the trigger teardown begins.) It’s also embedded below, so give it a peek.

A small amount of force applied in the right place can produce outsized results, but a force feedback project doesn’t have to be subtle. One can always shake things up by mounting a whole bunch of solenoids onto a mouse.

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