Operation of the capacitive touchscreen in heavy rain or snow
13 Nov 2014
A capacitive touchscreen can distinguish the conductivity of small water droplets from a fingertip or capacitive / active (charged) stylus, but it becomes more difficult as more water accumulates on the display. The touchscreen is continuously re-calibrating to adjust for any conductivity changes (such as new standing water droplets). Though as water droplets begin to gather, merge, and pool together, the touchscreen's ability to determine intentional user input becomes less accurate.
Limiting the amount of water that you allow to accumulate on the display or under the surrounding bezel can help. Operating the unit at an angle or vertically rather than horizontally can prevent or at least limit accumulation. Applying a hydrophobic coating (such as Rain-X) to the display may also be beneficial in such conditions. Simply flicking and / or wiping off moisture occasionally may also help.
A "Water" profile under the Start > Settings > System > Touch control panel applet is available (in OS release 1.4.4 or higher). Loading this profile tones down the sensitivity of the touchscreen to better ignore less conductive objects such as rain water droplets and only watch for more highly conductive objects such as a finger.
If using a capacitive stylus, it is recommended to tap with holding the stylus as perpendicular to the display as possible, rather than at an angle. Also, more conductive styli / gloves or even active (charged) styli may be available to improve the touchscreen's ability to distinguish intentional input. See the following web page for additional information.
As much as possible, try to limit software navigation and data entry to the hardware numpad or keyboard while operating in such conditions. If needed, key combinations and hot keys are available for movement and other additional input. During periods of inactivity (or when more exclusively operating using the hardware keys), the touchscreen can be temporarily disabled. See the product user guide (manual) for more specific information.
For some additional technical details, as previously mentioned the touch controller automatically calibrates to water (this can be good or bad depending on the size of water drops or accumulation). It will auto-calibrate 1.5 seconds after the last touch and every 1.5 seconds after that for up to 7 seconds of inactivity before it then goes to sleep. In OS release 1.4.1 and higher, the red cross hairs disappear roughly 1 second after each touch. If the touch controller is not behaving properly (such as due to excessive accumulated water on the display), then you could touch the screen in a non-active area, observe to make sure the red cross-hairs stay there after lifting the finger or stylus, then wait for 5 – 7 seconds before touching the screen again. This may correct erroneous input.
This is not as recommended, but if water is accumulating under the bezel around the display (possibly causing inaccurate or false input), and you are unable to readily drain, remove, or otherwise prevent such accumulation, a wax or other less conductive substance could be applied to fill the gap between the glass and bezel.