The rise of smartphone and smartwatch fitness tracking has been an absolute boon for anyone interested in tracking their runs. However, it all falls short when you need a custom feature and start getting into serious long distance running, as most smartphone batteries simply won’t last. While there are devices out there for the ultra-running enthusiast, [Ivor Hewitt] decided he wasn’t willing to pay a monthly subscription for the pricy trackers or deal with the hassle of the generic cheap versions, and decided to roll his own.
The key pieces of this project are the A9G GPS module and the RDA8955 GRS/GPRS module. They’re both incredibly small and power efficient, perfect for a project that needs to be worn on your person with a long battery life. As an added bonus, the RDA8955 also includes a SoC that’s user-programmable. After battling the lackluster documentation and tooling, [Ivor] managed to get some software running on his new system. A power bug on the A9G GPS module was potentially show stopping, but thanks to some help by folks in the community, it was diagnosed and solved.
Further additions included adding a proper charging circuit (TP4056) and a beefy 2600 mAh battery scavenged from a Sony smartphone, giving the compact system around 38 hours of active battery life. An OLED screen was added to show upcoming aid stations and overall system status, driven by a custom display library. A snazzy translucent case makes the whole device slim and easy to carry. Now at the end of a long race or training session, [Ivor] has a wealth of tracked points that has already been uploaded to his own tracking website and a fully charged phone.
Next time you’re looking for a small compact GPS tracker or cellular logger take a look at this project’s code on GitHub or the A9G and RDA8955 modules.
Thanks [Ivor] for sending this one in!
If I were doing something like this I’d try repurposing a Vaisalla RS4X radiosonde. Already has the MCU, serial port and GPS module, and runs on 3V. The 400-ish mhz Tx is a bonus and could be used to ring door bells on 433 or set off cafe “order is ready” buzzers as you go jogging.
I didn’t see if it was explained on his blog somewhere, but I do think it’s ironic that his solution to a cell phone battery not lasting long enough was to build his own tracker powered by… an old cell phone battery. Makes you wonder how it compares to simply bringing an external battery pack.
That’s easy to answer. Weight. When doing distance running the weight of what you have to carry is a major factor. Running ultras requires you to bring a lot with you (food, possibly a light jacket or another pair of shoes, enough water to get you to the next aid station, etc.). Even a older smart phone may be too heavy. A heavy external battery pack? Absolutely. This looks like a nice idea. Have to give it a more than cursory glance to make certain, but, from looking at it, I’d give it a try.
Hey,
almost completely selfishlyI want to point out one of my projects which might be helpful for other with the same/similar idear as Ivor. I buidl a Bluetooth GPS module which streams NMEA codes to a receiver. Maybe the schematic can be adopted to suit someones needs.
Project: https://hackaday.io/project/173514-bluetooth-gnss-module-with-u-blox-neo-m8n
regards.
love your project by the way ! Kudos for running ultra marathon, I myself only manage half-marathons at the moment.