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The operating principle of the capacitive keyboard is based on the electrical variation that occurs
when the user approaches the finger to the glass. With just approaching the finger there is already an
electrical variation detected by the system. However, for the selection of the function to be effective,
it is necessary to press on the key covering with the finger its maximum surface, thus creating the
effect of pulsation.
The software is responsible for immunizing the keyboard from the effects of water that may remain
on it. For this the system performs a series of individualized readings of each key obtaining a refe-
rence value for each one of them in the environmental conditions (humidity, more or less water on
the keyboard, but without the finger). When you press the key with your finger, this reference value
assigned to the key is far exceeded and the function is pressed and started.
If we move the finger little by little to the key, it will not cause the key to be pressed, because the
device assimilates it to a variation of the environment. Also, until we remove the finger for a few
seconds, the key will not respond adequately to a new press.
The slow increases in capacity are considered variations of the environment and the rapid ones that
are considered user pulsations. Thus, the approach of the finger to the key must be fast, the energe
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tic pulsation and covering the entire surface of the key.
When several keys are pressed at the same time, the device decides the one that was most pressed
or the one that was previously pressed, since by reliability several pulses are not allowed at the same
time.
When one or several keys are pressed (or excess water) more than 25 seconds, the logo flashes red
indicating an anomaly that the keyboard has something on it (a wet towel for example) that must be
removed or cleaned.
If water is poured on the keyboard and it remains stagnant, several keys may be pressed. To elimina-
te this effect, it is enough to remove the water.
There are factors that modify the sensitivity of the keyboard:
- The more finger surface touches the crystal, the greater the capacity variation.
- If the keyboard has a thin layer of water it will be less sensitive since this water film increases the
reference value.
- A layer of water can cause a different key to be pressed than the user wishes since the water being
conveyed transmits the variation of capacity to all the keys it covers.
- The fact that the user is inside the bathtub filled with water can increase the responsiveness of the
keyboard.
