Giving Your Pets A Digital Squeak

December 15, 2022 by Matthew Carlson 4 Comments

A pet tracker has a particularly grueling set of requirements: small, light, rugged, incredibly long battery life, safe for the pet, and cheap. [Mihai Cuciuc] was looking at the options and wasn’t thrilled with any of them. So as any hacker would, he rolled his own, dubbed Squeak.

It uses an RN2483 module as it is a LoRAWAN module with publically available firmware from Microchip itself. This means [Mihai] could add his code and keep the modem code without having to reverse engineer everything or add a second microcontroller. In addition to the modem, there’s a GPS unit connected via UART. The clever part is the dual voltage regulators — the one powering the GPS is enabled or disabled by the RN2483. In addition, the RAM V_BACKUP line is always powered, which means the RN2483 can power up the GPS and let it get a quick fix (thanks to the RAM backup line).

To maximize the chances of a packet making it through, he made them only have the bare essentials. There are return packets to change the tracker’s mode (such as uplink interval or how often to capture GPS). With some cloud support, [Mihai] created infrastructure to capture the packets and relay them to Telegram. He can request the last location, receive updates, and change modes.

We’ve got you covered if you’re interested in tracking some of your dog’s other habits.

Garmin HUD Got Discontinued, But Not Trashed

October 30, 2022 by Donald Papp 8 Comments

The Garmin HUD+ was a small Bluetooth device intended for the dashboard of a car, meant to be used as a GPS heads-up display for data from Garmin smartphone apps. It used a bright VFD (vacuum fluorescent display) which was viewed through a clear reflector, and displayed GPS information and directions. It was discontinued in 2015, but [Doz] was fond of his and used it happily until a phone upgrade meant it no longer worked. Was it destined for a landfill? Not if he had anything to say about it!

The first thing [Doz] tried was using an alternate Android app, but since it also didn’t work, it was time to sit back and reflect on the scope of the issue. In [Doz]’s case, he really only wanted some basic meaningful data displayed, and decided he could do away with the phone altogether if he had the right hardware. Continue reading “Garmin HUD Got Discontinued, But Not Trashed” →

A bike computer sits on a wooden background. The back of the bike computer has a 3D printed attachment with two white translucent zip ties running through the back.

Repairing A Bike GPS With 3D Printing

October 7, 2022 by Navarre Bartz 10 Comments

We love hacks that keep gadgets out of the trash heap, and [Brieuc du Maugouër] has us covered with this 3D printable replacement mount he designed for his bike GPS.

One of the most frustrating ways a gadget can fail is when a small, but critical part of the device fails. [du Maugouër] combined a 3D printed back and four M2x6mm screws to make a robust new mount to replace the broken OEM mount on his handlebar-mounted GPS. Slots for zip tie mounting are included in case the replacement mount breaks before yet another replacement can be printed. Apparently [du Maugouër] agrees with Chief O’Brien that “in a crunch, I wouldn’t like to be caught without a second backup.” [Youtube]

It’s exciting that we’re finally in a time when 3D printed replacement parts are living up to their potential. This would be a lot easier if more manufacturers posted 3D printed design files instead of getting them pulled from 3D file platforms, but makers will find a way regardless of OEM approval.

We’ve covered a lot of bike hacks over the years including DIY Bike Computers and GPS Trackers. Do you have a project that keeps something from becoming trash or might save the world another way? There’s still time to enter the Save the World Wildcard round of the Hackaday Prize (closes October 16th).

TickTag, a tiny GPS logger with 3d printed case, LiPo battery and a 1 Euro coin for size reference

Tiny GPS Logger For The Internet Of Animals

September 18, 2022 by Abe Connelly 35 Comments

[Trichl] has created a tiny GPS logger, called ‘TickTag’, designed as an inexpensive location tracking option for animal studies. The low cost, tiny form factor, and large power density of the LiPo battery give it the ability to track large populations of small animals, including dogs and bats.

The TickTag is capable of getting 10,000 GPS fixes from its 30 mAh cell. Each unit is equipped with an L70B-M39 GPS module controlled by an Atmel ATtiny1626 microcontroller and sports a tiny AXE610124 10-pin connection header for programming and communication. GPS data is stored on a 128 kB EEPROM chip with each GPS location fix using 25 bits for latitude, 26 bits for longitude, and 29 bits for a timestamp. Add it all up and you get 10 bytes per GPS data point (25+26+29=80), giving the 10k GPS fix upper bound.

To record higher quality data and extend battery life, the TickTag can be programmed to record GPS location data using variable frequency intervals or when geofencing bounds have been crossed.

Continue reading “Tiny GPS Logger For The Internet Of Animals” →

A RPI HAT For Synchronized Measurements

September 15, 2022 by Dave Rowntree 17 Comments

A team from the Institute for Automation of Complex Power System (ACS) at RWTH Aachen University have been working for a while on the analysis of widely distributed power systems. In a drive to move away from highly specialised (and expensive) electronics platforms, they have produced some instrumentation designed to operate with the Raspberry Pi platform, and an open source software stack. They call the platform the SMU (Synchronised Measurement Unit.) The SMU consists of a HAT sitting on an RPi3, inside a 3D printed box that is intended to attach to a DIN rail. After all, this is supposed to be an industrial platform.

Hardware wise, the star of the show is the Texas Instruments ADS8588S which is a 16-bit 8-channel simultaneous sampling ADC. This is quite a nice device, with 200 kSPS throughput and a per-channel programmable front end, packaged in a hacker-friendly 64-pin QFP. What makes this project interesting however, is how they solved the problem of controlling the sampled data acquisition and synchronisation.

1-PPS and BUSY edges converted to levels, then OR’d to trigger the DMA

By programming the ADC into byte-parallel mode, then using the BCM2837 Secondary Memory Interface (SMI) block together with the DMA, samples are transferred into memory with minimal CPU overhead. An onboard U-Blox Max-M8 GNSS module provides a 1PPS (top of second pulse) signal, which is combined with the ADC busy signal in a very simple manner, enabling both sample rate control as well as synchronisation between multiple units spread out in an installation. They reckon they can get synchronisation to within 180 ns of top-of-second, which for measuring relatively slow-changing power systems, should be enough. The HAT PCB was created in KiCAD and can be found in the SMU GitHub hardware section, making it easy to modify to your needs, or at least adjust the design to match the parts you can actually get your hands on.

Continue reading “A RPI HAT For Synchronized Measurements” →

Lawnmower Doesn’t Need A Base Station

August 5, 2022 by Al Williams 21 Comments

A recent tour of an old WWII-era aircraft carrier reminded us how hard navigation was before the advent of GPS. It used to be the work of skilled people to sight the sun or the stars and use giant books to figure out a vessel’s position. Now you just ask your phone to listen to some GPS satellites and you have precision undreamed of with other systems. But GPS sometimes isn’t enough. Just using conventional GPS, you can locate yourself to a couple of meters. The new L5 band, which isn’t on all satellites yet, can get you to about 30cm. But if you need better — up to around 1 or 2 cm — you need to use special techniques lumped together as GNSS enhancements. [Viktor] wanted to have an Arudino -based lawnmower, but wanted to use more conventional GPS techniques along with ultrawideband (UWB) ranging tags.

Given that the ranging anchors are in the mowing area, we aren’t sure why the mower even has GPS other than to geofence so you can’t start autonomous operations until you are in range of the tags. The three anchors are placed in a triangle, so if the robot knows the distance to each tag it can use some math to locate itself inside the area quite precisely.

Continue reading “Lawnmower Doesn’t Need A Base Station” →

Around GPS In 100 Videos

June 23, 2022 by Al Williams 9 Comments

Do you know what the IODC word in GPS data means? If so, great! If not, head over to see the 32nd of [Michel van Biezen’s] 100-part video series on GPS. You probably want to watch the other 31 videos before he gets too much further ahead of you, too. [Michel] reminds you of that professor you had in college who knows a whole lot about something. In fact, scanning his YouTube channel, he knows a lot about many topics ranging from optics, chemistry, kalman filters, and lots of electronics.

There is a dedicated playlist for the GPS videos dating back to 2016. So 32 videos in about six years. So you might have a little time to catch up. While the first video is pretty introductory as you might expect, by the time you get to video 7 the topics switch to things like the C/A code, BPSK, and gory details of all the frame data, including the IODC word.

Continue reading “Around GPS In 100 Videos” →