A new project recently shared on Hackaday outlines the creation of a device to help search and rescue operations find lost people in the wilderness. Eric Wiiliam mentions the build was inspired by the television show “North Woods Law,” where many of the lost people have working cell phones on them but no reception to get help. Taking advantage of this fact, the aptly named ResQ works by recording beacons sent out from a phone’s WiFi along with the GPS coordinates when the beacon is received.
Two variations were made of the project. One is a handheld gadget with a directional Yagi antenna attached to it, while the second one is a smaller variation with a stub antenna that is meant to be mounted on drones or radio-controlled aircraft. Both units will detect and record all beacons and associated MAC addresses on nearby phones. In addition, the GPS coordinates, as well as the time, will be recorded when the beacon is detected. This information is then saved to an SD card every time this event happens.
Both builds use a Wemos D1 mini Pro, which features the popular ESP8266 along with 16MB of flash. The system was prototyped and tested out on a breadboard before 3D printing a case to house the electronic guts of the system. Furthermore, a custom PCB was developed to act as a shield for the Wemos. The rest of ResQ's components consist of an SPI SD card reader and card, a small OLED display, a 2.4GHz Yagi antenna, BN220 GPS, SMA adapter, 3D-printed enclosures, and the Nano Talon Aircraft used for flight testing.
More recent updates to the project include laser-cut wood and acrylic cases, which can be provided as part of a kit for people looking to make their own. In fact, Wiiliam has made all the info needed to assemble one readily available — the code, schematics, bill of materials, and laser-enclsoure files.