Orbital Safety: The Challenges Of Surviving Space Junk

December 14, 2021 by 22 Comments

Hanging around in earth orbit is like walking into the middle of a Wild West gunfight — bullets are flying around everywhere, and even though none are purposefully aimed at you, one might have your name on it. Many of these bullets are artificial satellites that are actively controlled and monitored, but we also find dead satellites, remnants of satellites, discarded rocket stages, tools lost during spacewalks, and even flecks of paint and rust, much of it zipping around at multiple kilometers per second without any guidance.

While removing this space debris directly would be ideal, the reality is that any spacecraft and any spacesuit that has to spend time in orbit needs to be capable of sustaining at least some hits by space debris impacting it.

Orbital Mechanics

That it’s easy to create new debris should come as no surprise to anyone. What may take a bit more imagination is just how long it can take for this debris to make its way towards earth’s atmosphere, where it will uneventfully burn up. Everything in orbit is falling toward the earth, but its tangential velocity keeps it from hitting — like a marble spinning around the hole in a funnel. Drag from the planet’s atmosphere is the friction that eventually slows the object down, and where it orbits in the planet’s atmosphere determines how long this descent will take. Continue reading “Orbital Safety: The Challenges Of Surviving Space Junk” →

A robotic turret shooting plastic balls at a man

Automated Turret Keeps Dorm Clean, RoboCop Style

December 14, 2021 by 17 Comments

Students’ dorm rooms are not generally known to be the most orderly of places. Whether it’s mountains of dishes in the sink, piles of clothes waiting to be washed, or random bits and bobs strewn across the hallway, cleaning up is pretty low on the agenda for many dorm dwellers.

[Luis Marx] seems to have invented a useful solution to his (or his roommates’) sloppiness: a robotic turret that opens fire on anyone who leaves items unattended (video, in German, embedded below). This system uses a set of “clutter sensors” that can be placed in strategic locations around the house and will detect stray objects using ultrasonic sensors. If any are found, the main system is alerted through WiFi. The turret will then search for any persons in its vicinity and start shooting them with little plastic balls.

The turret in question is a beautifully-designed piece of kit made from 3D printed parts and controlled by an ESP32. It can swivel around its axis and tilt up and down using two servos, while its firing mechanism is driven by a DC motor. It tracks its target thanks to a camera-based object sensor that can recognize humans. The whole thing gives us a bit of a RoboCop vibe; we’d half expect it to shout Pick up those clothes. You have twenty seconds to comply.

While this might not be the definitive solution to messy dorm rooms, we like the creative thinking behind it. We’ve seen auto-targeting turrets before, but not in household applications like this. Of course there are plenty of other robots that can help you with domestic tasks.

Continue reading “Automated Turret Keeps Dorm Clean, RoboCop Style” →

Teardown: Verizon AC791L Jetpack 4G Mobile Hotspot

December 14, 2021 by 24 Comments

The saying “time and tide wait for no man” is usually used as a verbal kick in the pants, a reminder that sometimes an opportunity must be seized quickly before it passes by. But it can also be interpreted as a warning about the perpetual march of time and how it impacts the world around us. In that case, we would do well to add cellular technology to the list of proverbial things that wait for no one. Do you need 5G? No. Do you want it? Probably not. But it’s here, so be a good consumer and dump all your 4G hardware in the name of technical progress.

This line of logic may explain how the Verizon-branded Netgear AC791L 4G “Jetpack” hotspot you see here, despite being in perfect working order, found itself in the trash. The onset of 5G must have been particularly quick for the previous owner, since they didn’t even bother to wipe their configuration information from the device. In the name of journalistic integrity I won’t divulge the previous owner’s identity; but I will say that their endearing choice of WPA2 key, iluvphysics, makes for a nice fit with our publication.

A quick check of eBay shows these devices, and ones like it, are in ample supply. At the time of this writing, there were more than 1,500 auctions matching the search term “Verizon jetpack”, with most of them going for between $20 and $50 USD. We like cheap and easily obtainable gadgets that can be hacked, but is there anything inside one of these hotspots that we can actually use? Let’s find out.

Continue reading “Teardown: Verizon AC791L Jetpack 4G Mobile Hotspot” →

Oh Deere, Is That Right To Repair Resolution Troubling You?

December 14, 2021 by 103 Comments

Over the years a constant in stories covering the right to repair has come from an unexpected direction, the farming community. Their John Deer tractors, a stalwart of North American agriculture, have become difficult to repair due to their parts using DRM restricting their use to authorised Deere agents. We’ve covered farmers using dubious software tools to do the job themselves, we’ve seen more than one legal challenge, and it’s reported that the price of a used Deere has suffered as farmers abandon their allegiance to newer green and yellow machines. Now comes news of a new front in the battle, as a socially responsible investment company has the tractor giant scrambling to block their shareholder motion on the matter.

Deere have not been slow in their fight-back against the threat of right-to-repair legislation and their becoming its unwilling poster-child, with CTO Jahmy Hindman going on record stating that 98% of repairs to Deere machinery can be done by the farmer themself (PDF, page 5) without need for a Deere agent. The question posed by supporters of the shareholder action is that given the substantial risk to investors of attracting a right-to-repair backlash, why would they run such a risk for the only 2% of repairs that remain? We’d be interested to know how Deere arrived at that figure, because given the relatively trivial nature of some of the examples we’ve seen it sounds far-fetched.

It’s beyond a doubt that Deere makes high-quality agricultural machinery that many farmers, including at least one Hackaday scribe, have used to raise a whole heap of crops. The kind of generational brand loyalty they have among their customers simply can’t be bought by clever marketing, it’s been built up over a century and a half. As spectators to its willful unpicking through this misguided use of their repair operation we hope that something like this shareholder move has the desired effect of bringing it to a close. After all, it won’t simply be of benefit to those who wish to repair their tractor, it might just rescue their now-damaged brand before it’s too late.

Curious about previous coverage on this ongoing story? This article from last year will give context.

Header image: Nheyob / CC BY-SA 4.0

DIY Semi Auto Grinder Builds Itself (Sort Of)

December 14, 2021 by 12 Comments

[JSK-koubou] is no stranger to making tools to improve their work, and this latest video is yet another in a long list of such builds, just checkout their YT channel to see the many other examples. The tool being highlighted this time is a semi-automatic grinder (Video, embedded below) which could be very handy in many situations.

Many of us struggle a little to get straight cuts with an angle grinder, especially with softer materials, as it is sometimes hard to get a good ‘feel’ of how the cut is proceeding. Once the cut is started, thin blades will tend to ‘track’ in the slot, so if it starts off a little bit, the whole cut will be off. Most annoying. Anything to help keep things straight and square would help a lot, with the extra feature of a motorized drive enabling a constant cut rate, and presumably giving an increase in the cut quality.

Using the part completed rig to cut its own leadscrew

Since operation is hands-off, you could set it up, and leave it to do its thing, whilst you step aside, away from flying sparks, noise and the remote possibility of getting a splintered blade in your face, should the unthinkable happen. All good things.

The detailed build video shows what looks like a pretty solid construction, there are plans available on the accompanying website, but they do request a small donation of ¥1000 (less than $10 USD) to download them. Given the usefulness of the tool, this seems like a small price to pay. We quite liked some sections of the build video, where the tool is used to cut its own components, as it is built-up sequentially. Clever stuff! Another interesting technique to see was the use of a flame-heated (Stanley) knife blade as a drive belt end-jointer. Somewhat tough on the blade, but it’s a consumable item and gets the job done, so that’s good enough for us!

Parts wise, there’s nothing special at all here, with most easily sourced via the usual mechanical suppliers, but we reckon you’d be able to find most of it on eBay as well. We think this is exactly the sort of build that would work well in your local Makerspace, so perhaps give that a thought?

Bored with manually cutting off? Need an overkill solution for a mundane job? How about an Automatic Cut-Off Saw? If you need some defense against the mighty angle grinder, then perhaps Proteus is just the ticket?

Continue reading “DIY Semi Auto Grinder Builds Itself (Sort Of)” →

Pit Your Wits Against British Spooks

December 13, 2021 by 13 Comments

The festive season is upon us, and for Brits of a technical bent that means it’s time for the GCHQ Christmas Challenge. Sent out annually as part of the Christmas card from the UK’s intelligence centre, this is a chance for would-be spooks to pit their wits against some of the nation’s cleverest cryptologists whose work you’ll never have heard of.

This year the puzzle is aimed at those with a secondary school education, in the hope of fostering an interest in maths and science in younger people. It’s a series of puzzles of ascending difficulty, but don’t be lulled into a false sense of security by the earlier ones being easy, to complete the set will still require some brain power.

We’re guessing that as in previous years, this puzzle will garner a significant quantity of entries. It’s a successful public relations exercise from the agency which like all such organisations has felt its fair share of controversy in its time. There may thus be readers who regard it with some suspicion, but it’s fair to say it’s not the only such popular exercise from a govenment agency. If meanwhile you fancy a bit of GCHQ history, we caught their Science Museum exhibition back in 2019.

Anr air quality sensor mounted on a bike's handlebar

Measuring Air Quality Using Mobile Sensors For The Masses

December 13, 2021 by 8 Comments

Poor air quality is a major problem for city dwellers the world over. Dust, smoke, particles and noxious gases from vehicles, industry and agriculture makes many megacities downright hazardous to live in. Pinpointing the source of pollution and developing strategies for mitigation requires accurate data on pollutant levels, but obtaining these numbers is not always easy.

Enter CanAirIO, a citizen science project that aims to gather air quality data from around the world by putting sensors into the hands of as many people as possible. Its team has developed two different sensor nodes for this purpose: an indoor one that can measure CO2, and a mobile one that can measure particulate matter (PM) levels. Both versions are powered by an ESP32 microcontroller that reads out the air quality sensors and connects to the Internet using WiFi or BlueTooth. The data can then be shared online to create detailed maps showing local variations in air quality.

The design of the sensor nodes is fully open-source, allowing anyone with basic electronic skills to build them. The sensors are a Sensirion SCD30 for CO2 measurement and an SPS30 for PM levels. The mobile version comes with a neat 3D-printed enclosure that can be mounted on a bike’s handlebar, enabling the user to quickly gather data around their neighbourhood. A mobile app simplifies setting up the sensors and sharing the data.

The project has already been successful in gathering detailed data in the city of Bogotá, Colombia, and will no doubt prove useful in many other pollution hotspots around the world. We’ve seen similar community efforts to monitor air pollution and even radiation in various places, both showing how relatively simple devices can help to make a difference in people’s wellbeing. Continue reading “Measuring Air Quality Using Mobile Sensors For The Masses” →