In the study of collisions between two carts, it is desirable to collect position data for both carts. This can be done with a pair of Voyagers, each connected to separate devices running the PocketLab app. Starting data collection on both Voyagers by simultaneously clicking data recording on both PocketLab apps is difficult. One cannot view the data on a single device in real time, and analysis of data requires combining data from two separate devices.
It would be nice if one could connect two (or more!) Voyagers to the same device—say to an Android device or an iOS device running an app that could display concurrent data collection from both Voyagers. Such a capability is possible by the use of Phyphox (physical phone experiments), an app developed at the 2nd Institute of Physics of the RWTH Aachen University in Germany. The author of this lesson has been working with a pre-release Android version of this app that supports BLE (Bluetooth Low Energy) technology to transfer data from multiple Voyagers to the Phyphox app. Since that time, a public Android version of the Phyphox app has been released. The file Two Car Study 2.phyphox, accompnaying this lesson, can then be loaded into the Phyphox app.