How to Cure Switch Bounce to Reading the Key

Thread starter jyothika
Start date May 15, 2008
Tags

Bounce Reading Switch

In summary, switch bounce is a problem that occurs when a mechanical switch is pressed or released, causing multiple, rapid open and close contacts. This can lead to false readings and interfere with accurate data collection or device functioning. Switch bounce can affect key reading by causing multiple, rapid signals to be sent, making it difficult to determine the actual state of the key. Common techniques for reducing switch bounce include using debounce circuitry, adding capacitors or resistors to the circuit, and implementing software algorithms. To test for switch bounce, a multimeter or logic analyzer can be used. While switch bounce cannot be completely eliminated, it can be greatly minimized by implementing proper techniques and using high-quality switches.

May 15, 2008

jyothika

how to cure Switch Bounce? is it a good idea to read the key more than once?

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May 15, 2008

mgb_phys

Science Advisor

Homework Helper

You can do it analogly with a cap and a resistor or you can do it in software by reading the input a few times - it depends on the application.

May 15, 2008

berkeman

Mentor

You can also use cross-coupled NAND gates to debounce a switch, if the switch has two throws per pole.

Related to How to Cure Switch Bounce to Reading the Key

1. What is switch bounce and why is it a problem?

Switch bounce is a phenomenon that occurs when a mechanical switch is pressed or released, causing multiple, rapid open and close contacts. This can create false readings and interfere with accurate data collection or device functioning.

2. How does switch bounce affect key reading?

Switch bounce can cause multiple, rapid signals to be sent to the device, making it difficult to determine the actual state of the key. This can result in incorrect readings or commands being sent to the device.

3. What are some common techniques for reducing switch bounce?

Some common techniques for reducing switch bounce include using debounce circuitry, adding capacitors or resistors to the circuit, and implementing software algorithms to filter out false signals.

4. How can I test for switch bounce?

To test for switch bounce, you can use a multimeter to measure the voltage or resistance across the switch contacts while pressing and releasing the switch. Alternatively, you can use a logic analyzer to capture and analyze the signals sent by the switch.

5. Can switch bounce be completely eliminated?

While switch bounce can be reduced significantly, it cannot be completely eliminated. However, by implementing proper techniques and using high-quality switches, the effects of switch bounce can be greatly minimized.