Hardware

Robotics
Internet of Things
Electronics - For electronic engineers and hobbyists.
Bluetooth Beacons
Electric Guitar Specifications - Checklist for building your own electric guitar.
Plotters - Computer-controlled drawing machines and other visual art robots.
Robotic Tooling - Free and open tools for professional robotic development.
LIDAR - Sensor for measuring distances by illuminating the target with laser light.
Open Hardware - Open-source hardware projects.
ADS-B - Technology broadcasting aircraft's identity, position, and data periodically.
Flying FPV - Open hardware and software related to drones / UAVs.