A free app for Android, by Chrono Connect.
Chrono Connect Mobile is a tool to measure the power of your airguns. It works as a real chronograph, measuring the speed of the pellets leaving the gun and displaying the results in a range of power values.
The app works by reading the force of the pellets and the distance they travel. All of this information is displayed on the screen.
The app can measure the speed of the pellets in feet per second and the power in units of kilojoules and millijoules. It is very easy to use and set up.
The app can be used as a standalone tool or as a companion to a real chronograph.