Interposer Helps GPS Receiver Overcome Its Age

March 4, 2025 by 5 Comments

We return to [Tom Verbeure] hacking on Symmetricom GPS receivers. This time, the problem’s more complicated, but the solution remains the same – hardware hacking. If you recall, the previous frontier was active antenna voltage compatibility – now, it’s rollover. See, the GPS receiver chip has its internal rollover date set to 18th of September 2022. We’ve passed this date a while back, but the receiver’s firmware isn’t new enough to know how to handle this. What to do? Build an interposer, of course.

You can bring the module up to date by sending some extra init commands to the GPS chipset during bootup, and, firmware hacking just wasn’t the route. An RP2040 board, a custom PCB, a few semi-bespoke connectors, and a few zero-ohm resistors was all it took to make this work. From there, a MITM firmware wakes up, sends the extra commands during power-on, and passes all the other traffic right through – the system suspects nothing.

Everything is open-source, as we could expect. The problem’s been solved, and, as a bonus, this implant gives a workaround path for any future bugs we might encounter as far as GPS chipset-to-receiver comms are concerned. Now, the revived S200 serves [Tom] in his hacking journeys, and we’re reminded that interposers remain a viable way to work around firmware bugs. Also, if the firmware (or the CPU) is way too old to work with, an interposer is a great first step to removing it out of the equation completely.

Antique-Style GPS Looks Like Steampunky Fun

February 1, 2025 by 14 Comments

These days, turn-by-turn GPS navigation isn’t considered special anymore. It’s in every smartphone and most cheap rental cars, and thus everybody expects you to figure out where you’re going. If you want a simpler and less robust navigation experience, you might like to try the rather fancy RadioScout.

The RadioScout is a build from [hardlyhumanfx]—a group of engineers and artists that collaborate on fun and whimsical projects. It looks like some kind of steampunk compass, and it kind of is—but at heart, it’s powered by GPS.

You program the RadioScout using the buttons on the front panel and a rotary phone dial to enter the latitude and longitude of your destination. It then uses an internal GPS receiver to compare that with your current location, and calculates a direct bearing to where you want to go. This bearing is displayed with a large compass-like needle run by a stepper motor, and you you can use it to guide yourself onwards.

It’s an attractive build that uses lots of neat parts. The team interfaced a microcontroller with a GPS receiver, a rotary dial, and 7-segment LEDs for the latitude and longitude display. The very real bell is neat, too. The whole thing is wrapped up in a brass and wooden case that would make you a star at just about any sci-fi convention. The build video is a little vague on the finer details, but experienced makers will be able to figure out how it all works.

You can actually buy a RadioScout if it’s something you must have, but one suspects the Hackaday set would probably prefer the homebrew route.

Continue reading “Antique-Style GPS Looks Like Steampunky Fun” →

Before GPS There Was LORAN

January 6, 2025 by 38 Comments

We found it nostalgic to watch [ve3iku] fire up an old Loran-A receiver and, as you can see in the video below, he got it working. If you aren’t familiar with LORAN, it was a common radio navigation technique before GPS took over everything.

LORAN — an acronym for Long Range Navigation — was a US byproduct of World War II and was similar in many ways to Britain’s Gee system. However, LORAN operated at lower frequencies to improve its range. It was instrumental in helping convoys cross the Atlantic and also found use in the Pacific theater.

Continue reading “Before GPS There Was LORAN” →

An homemade automated air freshener dispenser

GPS Enabled Pumpkin Spice Sprayer Knows When It’s PSL Season

November 29, 2024 by 9 Comments

Pumpkin spice, also known as allspice with better marketing, has found its way into a seemingly endless amount of products over the years. It goes beyond the obvious foodstuffs of pies and cakes; because there are plenty of candles, deodorants, and air fresheners ready to add a little more spice to your world. One such autumnal smell enthusiast, YouTube user [J-Knows], sought to automate the delivery mechanism with his 3D printed pumpkin spice aerosol sprayer.

The sprayer device uses an Arduino to rotate a small 3D printed arm that depresses the button on an air freshener cap. This design came as a result of multiple attempts to create a clip that would securely attach to a standard canister. When problems arose with the clip slipping out of place after the motor rotated, a pinch of sticky tack ended up being just the solution. With the proper amount of adhesion, the automated sprayer could now “pollute” any space it is in, as [J-Knows] described.

What took this project to another level is the addition of an Adafruit GPS module. It was coded to respond when it was within one mile of a Starbucks — arguably the organization responsible for the pumpkin spice craze. For some the company’s pumpkin spice latte (PSL) is synonymous with all things fall, and marks the beginning of the season when it is brought back to the coffee menu. Though not being a regular coffee drinker himself, [J-Knows] fully committed to the bit by taking his creation on a test trip to his local Starbucks for a PSL. Judging by the amount of pumpkin spice aerosol solution that ended up on his car dash, he is going to be smelling it into the next year.

Continue reading “GPS Enabled Pumpkin Spice Sprayer Knows When It’s PSL Season” →

Tiny LoRa GPS Node Relies On ESP32

October 17, 2024 by 10 Comments

Sometimes you need to create a satellite navigation tracking device that communicates via a low-power mesh network. [Powerfeatherdev] was in just that situation, and they whipped up a particularly compact solution to do the job.

As you might have guessed based on the name of its creator, this build is based around the ESP32-S3 PowerFeather board. The PowerFeather has the benefit of robust power management features, which makes it perfect for a power-sipping project that’s intended to run for a long time. It can even run on solar power and manage battery levels if so desired. The GPS and LoRa gear is all mounted on a secondary “wing” PCB that slots directly on to the PowerFeather like a Arduino shield or Raspberry Pi HAT. The whole assembly is barely larger than a AA battery.

It’s basically a super-small GPS tracker that transmits over LoRa, while being optimized for maximum run time on limited power from a small lithium-ion cell. If you’re needing to do some long-duration, low-power tracking task for a project, this might be right up your alley.

LoRa is a useful technology for radio communications, as we’ve been saying for some time. Meanwhile, if you’ve got your own nifty radio comms build, or anything in that general milleu, don’t hesitate to drop us a line!

GPS Tracking In The Trackless Land

October 7, 2024 by 17 Comments

Need a weekend project? [Cepa] wanted a GPS tracker that would send data out via LTE or the Iridium network. Ok, maybe that’s one for a very long weekend. However, the project was a success and saw service crossing the Barents Sea in the Arctic. Not bad.

Apparently, [Cepa] is very involved in sharing tracks to odd and remote places. While you may not have cell service in the middle of the Barents Sea, you can always see Iridium. The device does make some sacrifices to the expense of satellite communications. On LTE, the system pings your location every ten seconds. Without it, it dials up the sat connection once an hour. However, it does store data on a SD card, so — presumably — you get caught up when you have a connection.

Continue reading “GPS Tracking In The Trackless Land” →

Misleading GPS, Philosophy Of Maps, And You

September 10, 2024 by 19 Comments

The oft-quoted saying “all models are wrong, but some are useful” is a tounge-in-cheek way of saying that at some level, tools we use to predict how the world behaves will differ from reality in some measurable way. This goes well beyond the statistics classroom it is most often quoted in, too, and is especially apparent to anyone who has used a GPS mapping device of any sort. While we might think that our technological age can save us from the approximations of maps and models, there are a number of limitations with this technology that appear in sometimes surprising ways. [Kyle] has an interesting writeup about how maps can be wrong yet still be incredibly useful especially in the modern GPS-enabled world. Continue reading “Misleading GPS, Philosophy Of Maps, And You” →