Abstract: Techniques for rejecting apparent (but false) touches caused by objects such as water droplets located in areas with parasitic capacitive paths to ground are disclosed. To minimize these false touches, one or more guard conductors can be located in proximity to the housing and driven with a stimulation signal to shield objects from being capacitively coupled to ground through the housing. In some examples images of touch can be obtained from a non-bootstrapped or bootstrapped scan and also an extended bootstrapped scan wherein the guard conductor is driven with a stimulation signal that has the same characteristics as the stimulation signal being applied to the sensed touch nodes. In some examples, the results of the extended bootstrapped scan can be subtracted from the non-bootstrapped or bootstrapped scan to identify and reject apparent touches resulting from capacitive coupling to ground.

Abstract: Techniques for rejecting apparent (but false) touches caused by objects such as water droplets located in areas with parasitic capacitive paths to ground are disclosed. To minimize these false touches, one or more guard conductors can be located in proximity to the housing and driven with a stimulation signal to shield objects from being capacitively coupled to ground through the housing. In some examples images of touch can be obtained from a non-bootstrapped or bootstrapped scan and also an extended bootstrapped scan wherein the guard conductor is driven with a stimulation signal that has the same characteristics as the stimulation signal being applied to the sensed touch nodes. In some examples, the results of the extended bootstrapped scan can be subtracted from the non-bootstrapped or bootstrapped scan to identify and reject apparent touches resulting from capacitive coupling to ground.

Abstract: A touch sensitivity of a touch-sensitive surface can be adjusted based on a state of a device including the touch-sensitive surface. The state of the device can be a first state or a second state. In the first state, for example, the touch sensing system of the device can be programmed to recognize and process a wide range of touch signals including relatively weak touch signals, which may correspond to water, liquid or other unintentional touches. In the second state, for example, the touch detection threshold can be adjusted to better reject water or unintended touches. In some examples, a ratio of measurements captured using the different types of scans of a selected touch node can be used to determine the state of the device.

Abstract: A touch sensitivity of a touch-sensitive surface can be adjusted based on a state of a device including the touch-sensitive surface. The state of the device can be a first state (e.g., a grounding condition unknown or inferred to be poorly-grounded) or a second state (e.g., grounding condition inferred to be well-grounded). In the first state, for example, the touch sensing system of the device can be programmed to recognize and process a wide range of touch signals including relatively weak touch signals, which may correspond to water, liquid or other unintentional touches. In the second state, for example, the touch detection threshold can be adjusted to better reject water or unintended touches in the second state. In some examples, a ratio of measurements captured using the different types of scans of a selected touch node can be used to determine the state of the device.