What Is a Foot Switch?
A foot switch is a switch operated with the foot.
The foot action can be used to turn power or electrical signals on or off, or to switch electrical circuits. By operating switches with the feet, the work being done by hand can be continued without interruption, leading to improved work efficiency.
It may also be used to share the operation between the hands and feet. It is also useful in places where switches cannot be handled by hand for hygienic reasons (operating rooms in hospitals, and food processing plants).
Uses of Foot Switches
Foot switches are used in a variety of fields, including measuring instruments, medical equipment, amusement equipment including music players, nursing care and welfare equipment, industrial machineries such as machine tools and presses, and digital equipment input.
Typical functions are switches that are turned on and off by foot movement, but there are many different types of switches in terms of shape and function depending on the industry in which they are used and the specifications required. For example, in applications where signals are input as external input devices for digital equipment, specific keys on a keyboard may be assigned to footswitches using dedicated software.
The purpose of this is to improve the efficiency of input operations by sharing the input operations using the hands by performing certain key operations that are pressed frequently with footsteps.
Principle of Foot Switches
The typical construction of a foot switch is a microswitch built into an enclosure that supports a foot pedal. The microswitch is pressed by stepping on the pedal.
The pedal and housing are made of aluminum alloy or ABS resin. Since the pedal is stepped on with the foot, it must be strong.
There are also foot switches that do not use a pedal, but have a structure in which a foot presses a pushbutton switch large enough that the foot can be stepped on without error.
Types of Foot Switches
1. Momentary Type and Alternate Type
The momentary type and the alternate type are classified according to the difference in the change of the electrical connection state due to the stepping motion.
Momentary Type
As the name implies, it means “momentary. It operates by turning on only while the switch is stepped on.
Alternate Type
As the name implies, it means “alternating. When you step on the switch, it switches on and remains on even when you take your foot off.
Then, when you step on the switch again, it switches off and remains off when you take your foot off. Each time you step on the switch, it alternates between on and off.
2. Latch Type and Unlatch Type
There are type and unlatch-type footswitches with different mechanical actions.
Latch Type
When the switch is turned on by stepping on it, it is held in the depressed position. Then, when you step on it again, the switch returns to its original position and turns off.
Unlatch Type
The switch returns to its original position once you step on it, whether it is turned on or off.
How to Select Foot Switches
1. Conditions and Environment of Use
First, as an electrical component, it is necessary to confirm that the voltage (AC or DC) and current ratings to be operated conform to the conditions of use.
Also, select a type that matches the operating environment, such as a type with a dust-proof cover or a rain-proof type.
2. Shape
The pedal type is the most common, but there are also round types that can be stepped on from either side in 360°, which should be selected according to the application.
3. Method of Operation
Select the type of operation (momentary/alternating, latching/unlatching) that best suits the intended use. However, there are some applications where virtually only one way of operation exists.
For example, a pedal switch for music performance that controls the extension of the sound while playing an electronic piano. It is advisable to check that the pedal force required for the operation is not too large or too small and that the latch has an appropriate feel.
4. Polarity
Electric switches that switch the signal current have polarity (which side of the signal wire plug is + and which side is -), and it is necessary to check that the polarity is in the intended direction.
For example, footswitches for musical performance may have different polarity depending on the manufacturer of the instrument. If a footswitch with opposite polarity is used, the operation of the switch will be reversed.