Considered as a location-aware game that takes place in cities and towns is the Urban Defender. It is situated inside the real world with its ball as the main interface of the game as shown in the below image. The game is based upon elements that are fundamental to people in urban situations such as districts and their habitants. The main action of the game is by throwing the ball against the wall where the containing quarter gets owned by the player. The ball encourages the player to continue the game, to grow his territory, to own the city as it becomes an artifact that embodies the power and strength of the player.

During the preparation, creating a shape with the GPS devices on the map is the first thing to be done. The shape desired looked like the one on the right side of the image below. The thinking-feeling location involves 3 recipes including moving through the urban space, engaging in social interaction, and physical interaction with the surroundings. Serial communication has been employed to get used to the Beagle Board and the Arduino Nano. The result can be seen in the video below.

The players are encouraged to discover the different ways of interaction for them. Since the location-awareness implies a high degree of moving and dynamic elements, a ball-shaped toy was made based on the starting point. Any interaction with a ball can be done like balancing, bouncing, kicking, throwing, and so on. The concept of the interaction can be seen below.

A huge amount of possible games is offered by this concept which was about claiming streets or buildings that is played outside in the real world. The video below shows the gameplay of Urban Defender.

The built-in hardware is protected by the two balls shown below that provide skin which includes Arduino Nano, Accelerometer, LEDs, Xbee, vibration motor, and the wires. The flight phase, bounce, and rebound are recorded by the first prototype as it gives feedback through the 4 LEDs outside. By pitching the ball very hard, some insulate contacts were registered during the test.

Some foamed material provides protection for the [arts inside the case since the core is now a cube with a strong case. A stable, serial radio communication Xbee in the images below was used to read the sensor inside the ball and to upload the code to the Arduino Nano.

The bounce is the main attribute from a ball and a very flexible foamed material, shown below, was used to ensure the bounciness

An external power port was installed in order to load the internal 9V battery. Another power port to run all the parts from an external power source was added while the ball was being charged as shown below.

A gym ball out of industrial rubber was the next skin. The ball was very bouncy because of the robustness and its very thick and stable rubber as shown below. The whole electronic and technology is inside the ball. The startup of the brain is shown in the below video. Other images show the construction of the ball.