Meshtastic is an open source software for microcomputers that allows you to share location information and send and receive messages with GPS assistance for about $30 even when your smartphone is out of reach during outdoor activities such as hiking or skiing.
Meshtastic expands GPS wireless communication technology without a mobile line used in smartphones, enabling location information sharing and message transmission and reception within a range of several kilometers. It can also be used for outdoor sports or finding lost children.
With Mesh Tastic, you can mark the location of other microcontrollers with arrows or send preset messages. Support devices are available for $30 in both the TTGO T-Beam and LoRa 32.
In addition, if you connect your smartphone and device using Bluetooth, you can create a group to share location information using the Android app or set a message in advance. The app is publicly available on GitHub and can be pre-registered on the Google Play Store. Meshtastic is currently in an alpha version, but it is expected to improve battery life and UI for Android apps in the future. Related information can be found here .