In May of 2000, then-President Bill Clinton signed a directive that would improve the accuracy of GPS for anyone. Before this switch was flipped, this ability was only available to the military. What followed was an onslaught of GPS devices most noticeable in everyday navigation systems. The large amount of new devices on the market also drove the price down to the point where almost anyone can build their own GPS tracking device from scratch.
The GPS tracker that [Vadim] created makes use not just of GPS, but of the GSM network as well. He uses a Neoway M590 GSM module for access to the cellular network and a NEO-6 GPS module. The cell network is used to send SMS messages that detail the location of the unit itself. Everything is controlled with an ATmega328P, and a lithium-ion battery and some capacitors round out the fully integrated build.
[Vadim] goes into great detail about how all of the modules operate, and has step-by-step instructions on their use that go beyond what one would typically find in a mundane datasheet. The pairing of the GSM and GPS modules seems to go match up well together, much like we have seen GPS and APRS pair for a similar purpose: tracking weather balloons.
Add a flux capacitor and a Mr. Fusion to a DeLorean and it becomes a time machine. But without those, a DeLorean is just a car. A 35-year old car at that, and thus lacking even the most basic modern amenities. No GPS, no Bluetooth — not even remote locks for the gullwing doors!
To fix that, [TheKingofDub] decided to deck his DeLorean out with an iPad dash computer that upgrades the cockpit experience, and we have to say we’re impressed by the results. Luckily, the space occupied by the original stereo and dash vents in the center console is the perfect size for an iPad mini, even with the Lightning cable and audio extension cable attached. A Bluetooth relay module is used to interface to the doors, windows, trunk, garage door remote, and outdoor temperature sensor. A WiFi backup camera frames the rear license plate. Custom software ties everything together with OEM-looking icons and a big GPS speedometer. The build looks great, adds functionality, and should make road trips a little easier.
When [TheKingofDub] finally gets sick of people complaining about where the BTTF guts are, maybe he can add a flux capacitor and time circuits.
To build any sort of autonomous vehicle, you need a controller. This has to handle all sorts of jobs – reading sensor outputs, controlling motors and actuators, managing power sources – controlling a vehicle of even moderate complexity requires significant resources. Modern cars are a great example of this – even non-autonomous vehicles can have separate computers to control the engine, interior electronics, and safety systems. In this vein, [E.N. Hering] is developing a modular autonomous vehicle controller, known as YAUVC.
The acronym stands for Yet Another Unmanned Vehicle Controller, though its former name – Fly Hard With A Vengeance – was not without its charms. The project is built around the concept of modularity and redundancy. The controller, designed primarily for flying vehicles, has an ATMega328P as its primary processor, into which various modules can be plugged in to handle different tasks.
This design choice has several benefits – having separate processors to handle individual jobs can make sense in real-time systems. You’d hardly want your quadcopter to crash because the battery management routines were stealing CPU time from the flight dynamics calculations. Instead, by offloading tasks to individual modules, each can run without interfering with the others. Modularity does come with drawbacks however — the problem of maintaining efficient communication between modules is one of them. [Hering] also plans to make sure the system can be set up to use multiples of the same module for redundancy – similar to modern flight systems in passenger aircraft that weigh the results of several computers to make decisions.
Much work has already been done – with the YAUVC platform already fleshed out with a backbone design as well as modules for WiFi, accelerometers and GPS navigation. We look forward to seeing YAUVC reaching flight-ready status soon!
[Paul] has put together an insanely small yet powerful tracker for monitoring all the things. The USB TinyTracker is a device that packages a 48MHz processor, 2G modem, GPS receiver, 9DOF motion sensor, barometer, microphone, and micro-SD slot for data storage. He managed to get it all to fit into a USB thumb drive enclosure, meaning that you can program it however you want in the Arduino IDE, then plug it into any USB port and let it run. This enables things like remote monitoring, asset tracking, and all kinds of spy-like activity.
One of the most unusual aspects of his project, though, is this line: “Everything came together very nicely and the height of parts and PCBs is exactly as I planned.” [Paul] had picked out an enclosure that was only supposed to fit a single PCB, but with some careful calculations, and picky component selection, he managed to fit everything onto two 2-layer boards that snap together with a connector and fit inside the enclosure.
We’ve followed [Paul’s] progress on this project with an earlier iteration of his GSM GPS Tracker, which used a Teensy and fit snugly into a handlebar, but this one is much more versatile.
The usual way of adding GPS capabilities to a project is grabbing an off-the-shelf GPS module, plugging it into a UART, and reading the stream of NMEA sentences coming out of a serial port. Depending on how much you spend on a GPS module, this is fine: the best modules out there start up quickly, and a lot of them recognize the logical AND in ITAR regulations.
For [Mike], grabbing an off-the-shelf module is out of the question. He’s building his own GPS receiver from the ground up using a bit of hardware and FPGA hacking. Already he’s getting good results, and he doesn’t have to futz around with those messy, ‘don’t build ballistic missiles’ laws.
The hardware for this build includes a Kiwi SDR ‘cape’ for the BeagleBone and a Digilent Nexus-2 FPGA board. The SDR board captures raw 1-bit samples taken at 16.268 MHz, and requires a full minute’s worth of data to be captured. That’s at least 120 Megabytes of data for the FPGA to sort through.
The software for this project first acquires the GPS signal by finding the approximate frequency and phase. The software then locks on to the carrier, figures out the phase, and receives the 50bps ‘NAV’ message that’s required to find a position solution for the antenna’s location. The first version of this software was exceptionally slow, taking over 6 hours to process 200 seconds of data. Now, [Mike] has improved the channel tracking code and made it 300 times faster. That’s real-time processing of GPS data, using commodity off-the-shelf hardware. All the software is available on the Gits, making this a project that can very easily be replicated by anyone. We would expect the US State Department or DOD to pay [Mike] a visit shortly.
Of course, this isn’t the first time someone has built a GPS receiver from scratch. A few years ago, less than 1-meter accuracy was possible with an FPGA and a homebrew RF board.
WiFi and Bluetooth have their use cases, but both have certain demands on things like battery life and authentication that make them unsuitable for a lot of low-power use cases. They’re also quite limited in range. There are other standards out there more suitable for low-power and wide area work, and thankfully, LoRa is one of them. Having created some LoRa pagers, [Moser] decided to head out and test their range.
Now, we’ve done range tests before. Often this involves sending one party out with a radio while the other hangs back at base. Cellphones serve as a communications link while the two parties go back and forth, endlessly asking “Is it working now? Hang on, I’ll take a few steps back — what about now?”
It’s a painful way to do a range test. [Moser]’s method is much simpler; set a cellphone to log GPS position, and have the pager attempt to send the same data back to the base station. Then, go out for a drive, and compare the two traces. This method doesn’t just report straight range, either — it can be used to find good and bad spots for radio reception. It’s great when you live in an area full of radio obstructions where simple distance isn’t the only thing affecting your link.
Build details on the pagers are available, and you can learn more about LoRa here. While you’re at it, check out the LoRa tag for more cool builds and hacks.
Put a message in a bottle and toss it in the ocean, and if you’re very lucky, years later you might get a response. Drop a floating Arduino-fied buoy into the ocean and if you’ve engineered it well, it may send data back to you for even longer.
At least that’s what [Wayne] has learned since his MDBuoyProject went live with the launching of a DIY drift buoy last year. The BOM for the buoy reads like a page from the Adafruit website: Arduino Trinket, an RTC, GPS module, Iridium satellite modem, sensors, and a solar panel. Everything lives in a clear plastic dry box along with a can of desiccant and a LiPo battery.
The solar panel has a view through the case lid, and the buoy is kept upright by a long PVC boom on the bottom of the case. Two versions have been built and launched so far; alas, the Pacific buoy was lost shortly after it was launched. But the Atlantic buoy picked up the Gulf Stream and has been drifting slowly toward Europe since last summer, sending back telemetry. A future version aims to incorporate an Automatic Identification System (AIS) receiver, presumably to report the signals of AIS transponders on nearby ships as they pass.
We like the attention to detail as well as the low cost of this build. It’s a project that’s well within reach of a STEM program, akin to the many high-altitude DIY balloon projects we’ve featured before.
Continue reading “Low-cost Drift Buoy Plies the Atlantic for Nearly a Year”