According to Dave Akerman, “One of the nice things about LoRa vs. traditional radio modulation techniques used by high-altitude balloons, is that LoRa chips include decoders.” This means that the receivers can be quite small and inexpensive. While he’s made trackers using Raspberry Pi and Arduino hardware to help him chase down balloons on foot, he's dreamed of having something wrist-mounted to do this job for quite some time.
This kind of lofty goal would normally mean a custom PCB and extensive hardware hacking. As it just so happens, however, he found a rather thick smartwatch that comes with LoRa functionality and GPS built-in. Not only that, but the LLilyGo TTGO-T-Watch features an ESP32 module and an STM32 processor which can both be programmed using the Arduino IDE.
Connecting to the ESP32 for programming is a matter of plugging in a USB-C connector, as well as bit of software configuration, while the STM32 does require an inexpensive ST-Link USB programmer and a custom cable. Still, considering the possibilities, the amount of hardware hacking involved here is quite minimal.
Akerman's new wearable device is able to receive GPS data, along with balloon telemetry, and shows the direction of the HAB (or presumably anything else) using calculations based on this data. Lots more info is also available via several custom screens. Code for this tracking watch setup can be found on GitHub, and perhaps we’ll see more hacks based around this exciting hardware in the future!