Push-button and touch controls

In modern electronic systems, push-button switches are widely used to control, allowing for complex switching of electrical circuits using the most quickly and easily performed control movements — pressing a finger with your hand. Pushbutton switches, grouped together, are called keypads or keyboards.

As switching nodes in low-power low-frequency circuits, standard microswitches are used. Button heads may have a square, rectangular or round shape, and for frequently used buttons round shape is not recommended. For reliable installation of a finger, the working surface of the buttons should have a slight concavity.

To reduce fatigue with frequent switching, the push force of the button should be less than 0.5 N; however, small efforts and a small working stroke do not allow using a kinesthetic analyzer and clearly indicating the fact of switching. In the most common buttons under the index finger, the pressure is 1 ... 2 N, and the working stroke is 2 ... 3 mm.

In the non-latching buttons, the switching is determined by the ascending force of the pressing finger and a slight click, determined by ear. Comfortable backlit buttons.

Along with the mechanically switchable buttons, the so-called touch control is widely used, using the effect of changing the capacitance of the electronic circuit to switch when the operator's finger is applied to a designated place. Due to the lack of mechanical movements, a visual indication of the state of the touch switch with the help of the PIO is required for fixing the switchings.

Tumblers Switches of this type are used in cases that require two or three discrete switch states that are clearly controlled visually or by touch. When converting toggle switches from one position to another, there should be a difference in the values ​​of elastic resistance, and when switching, a characteristic click. In the case of wide application tumblers, the length of the drive element is 10 ... 25 mm with a diameter of 3 ... 8 mm.

If there are a large number of toggle switches on the panel, they must be encoded with the shape of the drive element, dimensions and color.

Rotary switches. The controls of this type are designed for multi-position sequential switching of circuits or stepwise regulation of the parameters of radio electronic means.

To ensure a good grip with the hand, large teeth and cavities, evenly distributed around the circumference, are placed on the OS. As the resistance to movement on the switch axis increases, the diameter and height of the handles increase so as to ensure acceptable operator effort (1 ... 2 N). For these purposes, use the rotary switches "beak".

The main disadvantage of the rotary switches is the need to consistently perform all intermediate switchings, which, with a large difference in the initial and final positions (up to 20), requires a large number of additional control actions. This increases the control time and accelerates the wear of the switching node, all contacts of which work during any switching.

In modern electronic systems, rotary switches successfully push out the push-button control, free from the deficiencies noted.