PNJdrone is a free Android app developed by SteveChan that lets you control your 4-axis aircraft using your smartphone through WiFi. With this app, you can easily take real-time videos and photos from your aircraft, save them on your phone and share them with your friends.

The app has a user-friendly interface that allows you to control the aircraft's altitude, direction, and speed with ease. It also has a feature that helps you track your aircraft's location, making it easier for you to recover it in case it gets lost. PNJdrone is a great app for anyone who loves flying 4-axis aircraft and wants to take stunning aerial photos and videos.