Dual touch and gesture recognition in 4-wire resistive touchscreens

Enhanced user interface environments is a hot topic in industry. Multi-touch technologies based on projected capacitance are preferred in the consumer market as they provide a more friendly interaction with the user. Also, these technologies allow the tracking of an infinite number of fingers on the touch screen. However, resistive technologies cover applications gaps such as medical, automotive, or environments where wearing gloves is required. Additionally, resistive panels allow the use of basic stylus or pens which is essential for character recognition in Asian languages. Traditionally, resistive technologies have been used to detect the position of a single touch on the screen. The paper will describe how to detect the most common two finger gestures (zooms, pinches, and rotations) using inexpensive 4-wire resistive touch screens and how to detect the true location of dual touch with some modeling and calibration of the screen.