Converting On-Grid Electronics To Off-Grid

Husband and wife team [Jason & Kara] hail from Canada, and in 2018, after building their own camper, sold up their remaining earthly goods and headed south. If you’re not aware of them, they documented their journey on their YouTube channel, showing many interesting skills and hacks along the way. The video we’re highlighting today shows a myriad of ways to power all the DC-consuming gadgets this they lug along with them.

LiFePO4 batteries are far superior to lead acid for mobile solar installations.

Their heavily modded F-550 truck houses 12kWh of LiFePO4 batteries and a 1.5kW retractable solar array, with a hefty inverter generating the needed AC power. They weren’t too happy with the conversion losses from piles of wall warts that all drained a little power, knowing that the inverter that fed them was also not 100% efficient. For example, a typical laptop power brick gets really hot in a short time, and that heat is waste. They decided to run as much as possible direct from the battery bank, through different DC-DC converter modules in an attempt to streamline the losses a little. Obviously, these are also not 100%

Home, sorry, truck automation system

efficient, but keeping the load off the inverter (and thus reducing dependency upon it, in the event of another failure) should help stem the losses a little. After all as [Jason] says, Watts saved are Watts earned, and all the little lossy loads add up to a considerable parasitic drain.

One illustration of this is their Starlink satellite internet system consumes about 60W when running from the inverter, but only 28W when running direct from DC. Over the course of 24 hours, that’s not far off 1kWh of savings, and if the sun isn’t shining, then that 12kWh battery isn’t going to stretch as far.

There are far too many hacks, tips, and illustrations of neat space and power-saving solutions everywhere, to write here. Those interested in self-build campers or hacking a commercial unit may pick up a trick or two.

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Hackaday Links: March 26, 2023

Sad news in the tech world this week as Intel co-founder Gordon Moore passed away in Hawaii at the age of 94. Along with Robert Noyce in 1968, Moore founded NM Electronics, the company that would later go on to become Intel Corporation and give the world the first commercially available microprocessor, the 4004, in 1971. The four-bit microprocessor would be joined a few years later by the 8008 and 8080, chips that paved the way for the PC revolution to come. Surprisingly, Moore was not an electrical engineer but a chemist, earning his Ph.D. from the California Institute of Technology in 1954 before his postdoctoral research at the prestigious Applied Physics Lab at Johns Hopkins. He briefly worked alongside Nobel laureate and transistor co-inventor William Shockley before jumping ship with Noyce and others to found Fairchild Semiconductor, which is where he made the observation that integrated circuit component density doubled roughly every two years. This calculation would go on to be known as “Moore’s Law.”

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Citizen-Driven Network Monitors Public Service Radio For Natural Disaster Alerts

Time is of the essence in almost every emergency situation, especially when it comes to wildfires. A wind-driven fire can roar across a fuel-rich landscape like a freight train, except one that can turn on a dime or jump a mile-wide gap in a matter of seconds. Usually, the only realistic defense against fires like these is to get the hell out of their way as soon as possible and make room for the professionals to do what they can to stop the flames.

Unfortunately, most people living in areas under threat of wildfires and other natural disasters are often operating in an information vacuum. Official channels take time to distribute evacuation orders, and when seconds count, such delays can cost lives. That’s the hole that Watch Duty seeks to fill.

Watch Duty is a non-profit wildfire alerting, mapping, and tracking service that provides near-real-time information to those living in wildfire country. Their intelligence is generated by a network of experienced fire reporters, who live in wildfire-prone areas and monitor public service radio transmissions and other sources to get a picture of what’s going on in their specific area. When the data indicate an incident is occurring, maps are updated and alerts go out via a smartphone app. Reporters have to abide by a strict code of conduct designed to ensure the privacy of citizens and the safety of first responders.

While Watch Duty’s network covers a substantial area of California — the only state covered so far — there were still a significant number of dead zones, mostly in the more remote areas of the Sierra Nevada Mountains and in the northern coastal regions. To fill these gaps, Watch Duty recently launched Watch Duty Echo, which consists of a network of remote listening posts.

Each station is packed with RTL-SDR receivers that cover a huge swath of spectrum used by the local fire, law enforcement, EMS agencies — any organization likely to be called to respond to an incident. In addition, each station has an SDR dedicated to monitoring ADS-B transponders and air band frequencies, to get a heads-up on incidents requiring aerial support. The listening posts have wideband discone antennas and a dedicated 1090-MHz ADS-B antenna, with either a cellular modem or a Starlink terminal to tie into the Watch Duty network.

Hats off to the folks at Watch Duty for putting considerable effort into a system like this and operating it for the public benefit. Those who choose to live close to nature do so at their own risk, of course, but a citizen-driven network that leverages technology can make that risk just a little more manageable.

When [Elon] Says No, Just Reverse Engineer The Starlink Signal

We all know that it’s sometimes better to beg forgiveness than ask permission to do something, and we’ll venture a guess that more than a few of us have taken that advice to heart on occasion. But [Todd Humphreys] got the order of operations a bit mixed up with his attempt to leverage the Starlink network as a backup to the Global Positioning System, and ended up doing some interesting reverse engineering work as a result.

The story goes that [Todd] and his team at the University of Texas Austin’s Radionavigation Lab, on behalf of their sponsors in the US Army, approached Starlink about cooperating on a project to make their low-Earth orbit constellation provide position, navigation, and timing capabilities. Although initially interested in the project, Starlink honcho [Elon Musk] put the brakes on things, leaving [Todd]’s team high and dry. Not to be dissuaded, they bought a Starlink user terminal, built what amounts to a small radiotelescope — although we’ve seen something similar done with just an RTL-SDR — and proceeded to reverse-engineer the structure of Starlink’s Ku-band downlink signal. The paper (PDF link) on their findings is densely packed with details, such as the fact that Starlink uses an orthogonal frequency-division multiplexing (OFDM) scheme.

It’s important to note that their goal was not to break encryption or sniff in on user data; rather, they wanted access to the synchronization and timing signals embedded in the Starlink data structures. By using this data along with the publically available ephemera for each satellite, it’s possible to quickly calculate the exact distance to multiple satellites and determine the receiver’s location to within 30 meters. It’s not as good as some GPS-Starlink hacks we’ve seen, but it’s still pretty good in a pinch. Besides, the reverse engineering work here is well worth a read.

Thanks to [Adrian] for the tip!

Snooping On Starlink With An RTL-SDR

With an ever-growing constellation of Starlink satellites whizzing around over our heads, you might be getting the urge to start experimenting with the high-speed internet service. But at $100 or more a month plus hardware, the barrier to entry is just a little daunting for a lot of us. No worries, though — if all you’re interested in is tracking [Elon]’s birds, it’s actually a pretty simple job.

Now, we’re not claiming that you’ll be able to connect to Starlink and get internet service with this setup, of course, and neither is the delightfully named [saveitforparts]. Instead, his setup just receives the beacon signals from Starlink satellites, which is pretty interesting all by itself. The hardware consists of his “Picorder” mobile device, which sports a Raspberry Pi, a small LCD screen, and a host of sensors, including an RTL-SDR dongle. To pick up the satellite beacons, he used a dirt-cheap universal Ku-band LNB, or low-noise block downconverter. They’re normally found at the focal point of a satellite TV dish, but in this case no dish is needed — just power it up with a power injector and point it to the sky. The signals show up on the Picorder’s display in waterfall mode; curiously, the waterfall traces look quite similar to the patterns the satellites make in the night sky, much to the consternation of astronomers.

Of course, you don’t have to have a Picorder to snoop in on Starlink — any laptop and SDR should work, despite [saveitforparts]’ trouble in doing so. You shouldn’t have much trouble replicating the results by following the video below, which also has a few tips on powering an LNB for portable operations.

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Starlink Ground Stations Successfully Hacked

Belgian security researcher [Lennert Wouters] has gotten his own code running on the Starlink “Dishy McFlatface” satellite terminals, and you can too! The hack in question is a “modchip” with an RP2040 and a MOSFET that crowbars the power rails, browning out the main CPU exactly when it’s verifying the firmware’s validity and bypassing that protection entirely. [Lennert] had previously figured out how to dump the Starlink firmware straight from the eMMC, and with the ability to upload it back, the circle of pwnership is closed. This was a talk at DEFCON, and you can check out the slides here. (PDF)

The mod chip itself was a sweet piece of work, being tailored to fit into the Starlink’s motherboard just so, and taking good advantage of the RP2040’s PIOs, which are probably the microcontroller’s superpower.

[Lennert] says he submitted his glitch attack to Starlink and they took some precautions to make the glitching harder. In particular, [Lennert] was triggering his timing off of the USART port coming up on the Starlink unit, so Starlink just shut that down. But it’s not like he couldn’t trigger on some other timing-relevant digital signal, so he chose the eMMC’s D0 data line: they’re not going to be able to boot up without it, so this hack is probably final. No shade against Starlink here. It’s almost impossible to shield a device against an attacker who has it on their bench, and [Lennert] concludes that he found no low-hanging fruit and was impressed that he had to work so hard to get root.

What can you do with this? Not much, yet. But in principle, it could be used to explore the security of the rest of the Starlink network. As reported in Wired, Starlink says that they’ve got a defence-in-depth system and that just getting into the network doesn’t really get you very far. We’ll see!

Thanks [jef] for the tip!

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Hackaday Links: July 3, 2022

Looks like we might have been a bit premature in our dismissal last week of the Sun’s potential for throwing a temper tantrum, as that’s exactly what happened when a G1 geomagnetic storm hit the planet early last week. To be fair, the storm was very minor — aurora visible down to the latitude of Calgary isn’t terribly unusual — but the odd thing about this storm was that it sort of snuck up on us. Solar scientists first thought it was a coronal mass ejection (CME), possibly related to the “monster sunspot” that had rapidly tripled in size and was being hyped up as some kind of planet killer. But it appears this sneak attack came from another, less-studied phenomenon, a co-rotating interaction region, or CIR. These sound a bit like eddy currents in the solar wind, which can bunch up plasma that can suddenly burst forth from the sun, all without showing the usually telltale sunspots.

Then again, even people who study the Sun for a living don’t always seem to agree on what’s going on up there. Back at the beginning of Solar Cycle 25, NASA and NOAA, the National Oceanic and Atmospheric Administration, were calling for a relatively weak showing during our star’s eleven-year cycle, as recorded by the number of sunspots observed. But another model, developed by heliophysicists at the U.S. National Center for Atmospheric Research, predicted that Solar Cycle 25 could be among the strongest ever recorded. And so far, it looks like the latter group might be right. Where the NASA/NOAA model called for 37 sunspots in May of 2022, for example, the Sun actually threw up 97 — much more in line with what the NCAR model predicted. If the trend holds, the peak of the eleven-year cycle in April of 2025 might see over 200 sunspots a month.

So, good news and bad news from the cryptocurrency world lately. The bad news is that cryptocurrency markets are crashing, with the flagship Bitcoin falling from its high of around $67,000 down to $20,000 or so, and looking like it might fall even further. But the good news is that’s put a bit of a crimp in the demand for NVIDIA graphics cards, as the economics of turning electricity into hashes starts to look a little less attractive. So if you’re trying to upgrade your gaming rig, that means there’ll soon be a glut of GPUs, right? Not so fast, maybe: at least one analyst has a different view, based mainly on the distribution of AMD and NVIDIA GPU chips in the market as well as how much revenue they each draw from crypto rather than from traditional uses of the chips. It’s important mainly for investors, so it doesn’t really matter to you if you’re just looking for a graphics card on the cheap.

Speaking of businesses, things are not looking too good for MakerGear. According to a banner announcement on their website, the supplier of 3D printers, parts, and accessories is scaling back operations, to the point where everything is being sold on an “as-is” basis with no returns. In a long post on “The Future of MakerGear,” founder and CEO Rick Pollack says the problem basically boils down to supply chain and COVID issues — they can’t get the parts they need to make printers. And so the company is looking for a buyer. We find this sad but understandable, and wish Rick and everyone at MakerGear the best of luck as they try to keep the lights on.

And finally, if there’s one thing Elon Musk is good at, it’s keeping his many businesses in the public eye. And so it is this week with SpaceX, which is recruiting Starlink customers to write nasty-grams to the Federal Communications Commission regarding Dish Network’s plan to gobble up a bunch of spectrum in the 12-GHz band for their 5G expansion plans. The 3,000 or so newly minted experts on spectrum allocation wrote to tell FCC commissioners how much Dish sucks, and how much they love and depend on Starlink. It looks like they may have a point — Starlink uses the lowest part of the Ku band (12 GHz – 18 GHz) for data downlinks to user terminals, along with big chunks of about half a dozen other bands. It’ll be interesting to watch this one play out.