Researchers develop disposable paper-based touch pads

Via Phys Org

-----

A paper-based touch pad on an alarmed cardboard box detects the change in capacitance associated with the touch of a finger to one of its buttons.

The keypad requires the appropriate sequence of touches to disarm the system. Image credit: Mazzeo, et al.

The touch pads are made of metallized paper, which is paper coated in aluminum and transparent polymer. The paper can function as a capacitor, and a laser can be used to cut several individual capacitors in the paper, each corresponding to a key on the touch pad. When a person touches a key, the key’s capacitance is increased. Once the keys are linked to external circuitry and a power source, the system can detect when a key is touched by detecting the increased capacitance.

According to lead researcher Aaron Mazzeo of Harvard University, the next steps will be finding a power source and electronics that are cheap, flexible, and disposable.

Among the applications, inexpensive touch pads could be used for security purposes. The researchers have already developed a box with an alarm and keypad that requires a code to allow authorized access. Disposable touch pads could also be useful in sterile or contaminated medical environments.