The position could refer to screen position, or physical position in the real world. The smartphone has been used for Kitchen Knife Holder Factory positioning tasks in a variety of ways: such as· Continuousin direct translation with a track pad. Remote Commander enables individuals touse the touch screen on a PDA as a trackpad to control the relative position ofa cursor on a remote display.· Continuousindirect translation with velocity-controlled joystick. A return-to-zerojoystick controls the velocity of a continuously repositioned object. Zerodisplacement of the joystick corresponds to zero velocity. Silfverberg et al. has done an in-depth study of isometricjoysticks on handheld devices to control the cursor on a public display.

Many of todays mobile phones are shipping with binary resolution, 4 to 8 direction,return-to-zero joysticks.· Continuousindirect translation with accelerometers. Accelerometers are beginning toemerge in handheld devices such as Samsungs SCH-S310 mobile phone with anintegrated 3-D accelerometer. Rock n Scroll allows users to scroll (e.g.through an electronic photo album) by tilting the handheld device. Althoughthis technique was used to interact with an application directly on the device,it could clearly be extended to positioning tasks in ubiquitous computingenvironments.· Continuousindirect translation with directional step keys. The location of an object iscontrolled by using up, down, left, right step keys for 2-D applications, plusin and out for 3-D. In the Blinkenlights project, users played the arcadeclassic Pong using the side of a building as a large public display.

Eachwindow equalled one pixel on the 18x8 pixel display. Players connected to thedisplay by making a standard call to a phone number. Pressing the number 5 onthe phone keypad moves the paddle up, and the number 8 moves it down.· Continuousdirect translation with camera tracking. Madhavapeddy et al. presentscamera-based interactions involving tagging interactive GUI elements such assliders and dials. In manipulating the position and orientation of the phonecamera, the user can position a graphical slider, or orient a graphical dial.An analogy can be drawn to the classic light pen with a tracking cross. As thelight pen moves to a new position, the cross follows the motions of the pen.