- #1
Furion
- 3
- 0
Ive been working on a new project for my studies but can't seem to get any info on 'switch bounce'
In summary, Switch bouncing is the electrical noise made by metal coming together to form a circuit. It lasts maybe 40ms depending on the switch. Switch debounce is the process of getting rid of switch bounce.
- #2
Antiphon
- 1,686
- 4
It's the electrical noise made by metal coming together to form a circuit. It lasts maybe 40ms depending on the switch.
Google "switch debouncing circuit" and you'll get lots of examples.
Google "switch debouncing circuit" and you'll get lots of examples.
- #3
dlgoff
Science Advisor
Gold Member
- 4,433
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If you are interested in cleaning up switch bounce (switch debounce), you can do it with a couple of nand gates.
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/setreset.html"
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/setreset.html"
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- #4
Furion
- 3
- 0
Is switch bouncing and de bouncing the same?because I am not sure
- #5
Feldoh
- 1,342
- 3
Switch debounce and switch bounce are two different things.
Switch Bounce happens when you close a mechanical switch. When you close a switch it tends to literally bounce upon the metal contact which connects the circuit.
It's almost like dropping a basketball. The basketball will hit then ground (analogous to a closed switch) then bounce back up (analogous to a open switch) then bounce back down, then up, then down, etc... until it permanently stays on the ground (permanently closed).
Usually switches take a few microseconds to a few milliseconds to completely close. What this means in terms of digital logic is that as the switch physically bounces your logic can switch back and forth low-to-high-to-low-etc... until your switch settles down.
Switch Debounce is the process of getting rid of switch bounce. One solution to get rid of switch bounce is given above by dlgoff
Switch Bounce happens when you close a mechanical switch. When you close a switch it tends to literally bounce upon the metal contact which connects the circuit.
It's almost like dropping a basketball. The basketball will hit then ground (analogous to a closed switch) then bounce back up (analogous to a open switch) then bounce back down, then up, then down, etc... until it permanently stays on the ground (permanently closed).
Usually switches take a few microseconds to a few milliseconds to completely close. What this means in terms of digital logic is that as the switch physically bounces your logic can switch back and forth low-to-high-to-low-etc... until your switch settles down.
Switch Debounce is the process of getting rid of switch bounce. One solution to get rid of switch bounce is given above by dlgoff
- #6
MATLABdude
Science Advisor
- 1,663
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If you are doing microprocessor/controller work (e.g. with an externally-triggered interrupt), it's quite common practice to pause for a period of time (~20 ms or so) upon receiving an input in order to debounce a button / switch / relay.
A friend of mine nearly tore his hair out trying to fix an interrupt service routine where he'd forgotten to do this.
A friend of mine nearly tore his hair out trying to fix an interrupt service routine where he'd forgotten to do this.
- #7
Furion
- 3
- 0
ohh I get it now make a lot sense now thanks guys
FAQ: What is Switch Bounce? | Project Study Info
1. What is switch bounce?
Switch bounce is a phenomenon that occurs when an electrical switch is pressed or released. It causes rapid, multiple changes in the state of the switch, resulting in an unstable or noisy output signal.
2. Why is switch bounce a problem?
Switch bounce can cause errors in electronic circuits, as the multiple changes in the switch's state can be interpreted as multiple presses or releases. This can lead to incorrect signals being sent and received, compromising the functionality of the circuit.
3. How does switch bounce affect electronic devices?
Switch bounce can cause electronic devices to malfunction or not function at all. For example, in a keyboard, switch bounce can result in the wrong characters being typed or keys not registering at all.
4. What are some common methods used to eliminate switch bounce?
There are various methods used to eliminate switch bounce, such as adding a debounce circuit, using software debouncing techniques, or using specialized switches designed to reduce bounce. Mechanical solutions like adding springs or dampening materials to the switch can also help reduce bounce.
5. Are there any potential downsides to eliminating switch bounce?
While eliminating switch bounce can improve the functionality of electronic circuits, it can also increase the complexity and cost of the circuit. Additionally, some methods of debouncing may introduce a delay in the switch response, which may not be desirable in certain applications.