https://www.meshtastic.org/ https://news.ycombinator.com/item?id=22540066 An opensource hiking, pilot, skiing, Signal-App-extending GPS mesh communicator Meshtastic is a project that lets you use inexpensive ($30 ish) GPS radios as an extensible, super long battery life mesh GPS communicator. These radios are great for hiking, skiing, paragliding - essentially any hobby where you don’t have reliable internet access. Each member of your private mesh can always see the location and distance of all other members and any text messages sent to your group chat. https://github.com/iliasam/OpenTOFLidar Open Hardware scanning laser rangefinder based on Time-of-Flight principle. No standalone laser rangefinder modules were used in this LIDAR, so its schematic and firmware are fully open. https://www.vusec.net/projects/trrespass/