ShiftTouch: Extending Touchscreens with Passive Interfaces using Small Occluded Area for Discrete Touch Input

We present ShiftTouch, an attachment-type passive interface that provides multiple inputs for capacitive touchscreens with minimal screen occlusion. ShiftTouch utilizes multiple linear electrodes to control the fine displacement of the touch position. The touch input is activated under the electrodes when several adjacent electrodes are grounded simultaneously. Each input area shares several electrodes with neighboring input areas, and the touchscreen identifies each one by detecting the fine displacement of the touch position. ShiftTouch can effectively reduce the occlusion area while inheriting the advantages of existing touch extension interfaces, which are battery-free, freely detachable, and easy to construct. Depending on the number of inputs to implement, ShiftTouch can alleviate screen occlusion by up to 80.5% compared to existing approaches using finger-sized electrodes.