There exists a cool interface between ROS and Android. As you know, Android is one of most popular operating systems in mobile devices. Just imagine: if we can access all features of a mobile devices on the ROS network, we can build robots using it, right? We can build Android apps with ROS capabilities and can make any kind of robot using it, its scope is unlimited.
The following shows how the communication between android device and ROS robot is happening. The figure shows an example Android-ROS application which can teleoperate robot from an android device. Each android application should inherit from RosActivity which is getting from Android-ROS interface, then only we can access ROS API's in our application. We can see more about the API's after this section.
The core backend of the Android ROS library is RosJava (http://wiki.ros.org/rosjava), which is an implementation of ROS in Java. There is also Android core libraries (http://wiki.ros.org/android_core) which are built using RosJava API's. Using Android-ROS APIs we can create ROS nodes and ROS master, but compared to actual ROS API's in C++/Python, the Android-ROS features are less.
So what is the importance of Android-ROS interface? The main reason is, an Android device is like a mini computer, which is having all the sensors and other peripherals. We may can use an android device itself as a robot too. So if there is a ROS interface, we may can expand its capabilities by performing high level functionalities like navigation, mapping and localization. Nowadays, android devices are having high quality cameras, so we can even do image processing application via ROS interface.
Smartphone based robots are already in the market, we can also expand existing robots features by using ROS interface.
In the next section, we are going to see how to set up the ROS-Android interface on your PC and generate the Android Package Kit (APK) file, which can be directly installed on Android devices. Let's start setting up the ROS-Android interface on Ubuntu.
Before setting up Android, there is a long list of prerequisites that have to be satisfied for compiling and building it. Let's see what they are.