Mechanical switches experience “bounce,” which is a brief separation of contacts when the switch is closed. This results in the contacts making contact, bouncing away, and then making contact again several times within a nanosecond. When microcontrollers operate mechanical switches, the switch operation change is notified to the software, preventing multiple on/off messages from being delivered. As a result, switch bounce must be considered when using mechanical switches with microcontrollers.
FAQ About Switch Bounce
What Is Switch Bounce?
Switch bounce is a term used to describe the phenomenon that occurs when a mechanical switch is closed. In less than a nanosecond, the contacts make contact, bounce away, then make contact again several times. This brief separation of contacts can cause unwanted electrical signals or errors in a system.
Why is Switch Bounce Important?
Switch bounce is important because it can cause a lot of problems in electronic circuits. For example, if you are using a switch to turn on a motor, switch bounce can cause the motor to turn on and off multiple times before settling into a steady state. This can cause the motor to wear out faster than expected or cause other problems in the circuit.
How Is Switch Bounce Solved?
When microcontrollers are used to operate mechanical switches, the hardware alerts the software that the switch operation has changed. The software can then filter out the unwanted bounce signals and ensure that only one signal is delivered. This ensures that the system operates correctly and avoids any unwanted errors.
What Are Some Common Methods to Deal With Switch Bounce?
There are a few common methods used to deal with switch bounce. One method is to use a software-based approach where the microcontroller filters out unwanted signals. Another option is to use hardware debounce circuits that use capacitors or resistors to filter out the unwanted signals.
Switch bounce is an important phenomenon that can cause problems in electronic circuits. By understanding how switch bounce works and using the right methods to mitigate it, engineers can ensure that their systems operate correctly and avoid any unwanted errors. Whether you are designing a simple hobby circuit or a complex industrial system, it is important to keep switch bounce in mind and use the right techniques to deal with it.