S-TouchTM Capacitive Touch Controller PCB Layout Guide 4

Figure 5 Touch Button Shape

Touch buttons can be designed in various shapes, such as square, round, triangular, or other forms. If the PCB size is limited, the designed button shape should maximize space utilization to achieve optimal sensitivity.

For applications with a 2-3 millimeter acrylic plastic-coated shell, it is recommended to use square sensing electrodes with a minimum size of 10 x 10 millimeters. The maximum size should not exceed 15 x 15 millimeters. Exceeding this size will not improve sensitivity but will also increase susceptibility to noise.  diode

Touch the slider

The basic function of the touch slider is to detect the sliding position of a finger in a one-dimensional direction.

One typical application of the touch slider is for volume control. There are two methods to implement the touch slider: the touch state slider and the proportional meter slider.

By arranging the square touch buttons in close succession in order, a touch-state slider can be designed.diode

Figure 6: Implementation of the Touch State Slider

Position Sensor ON

Table 1 Design of the Touch State Slider

When a sensing channel is detected in an active state, the position of the finger on the slider can be determined. In the example above, five sensing channels are used to detect nine positions. If both S1 and S2 channels are active simultaneously, it indicates that the finger's position is at position 2.

For applications with a 2-3 mm acrylic plastic-coated housing, it is recommended to use sensing electrodes with a minimum size of 10 x 10 mm. The gap between sliding bar sensors is advised to be 0.75 mm. The gap between two adjacent sensing electrodes should not exceed 1 mm to ensure that both sensor channels can be activated simultaneously when a finger is precisely positioned within the gap.