Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [button]

Please do not use this tag. Use a "switch" tag instead

425 questions
35
votes
7 answers

Debouncing buttons

I recently read an article about button debouncing and was wondering if I should keep this in mind when working with, for example, an Arduino (ATMega mC)? I assume it is an issue, especially when working with interrupts. So is it better to detect…
Vincent Van Den Berghe
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31
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7 answers

Smart ways to detect a button (less power consuming)

During a meeting for a particular project I was asked to think about the way to detect a push on a button with a MCU. The detection should consume as little power as possible. At the first glance, I thought the typical circuit with a pull-up or a…
vionyst
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28
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3 answers

Is it possible to use just a capacitor to debounce a button?

I have been wondering: why cannot you just hook up a capacitor to a button to debounce it? I have been figuring out how to reduce the work my microprocessor has to do, but I have very limited space on a PCB I am designing, so I don't want to do a…
Anonymous Penguin
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3 answers

What's the purpose of traces that are later punched out?

I've found this odd feature on an FPC in a Camera than handles button and switch input. You can see there are traces that look like they were once connected and later punched out to be cut. The one on the left once short-cut a button, which would…
iFreilicht
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17
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2 answers

What's the purpose of a tactile switch with GND pin?

Some 5 pin or 3 pin tactile switches have an extra GND pin such as this Omron B3W-1150. What's the purpose of this pin?
HeyYO
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13
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3 answers

Physics behind switch bounce when opening?

I was surprised to learn that a mechanical switch (SPST) bounces when it is opened. What causes the contact to temporarily return to touching? Does this phenomenon only happen with certain types of switches (e.g., with sliding switches but not with…
Richard Hansen
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11
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3 answers

How does the telephone's keypad work?

I disassembled some old telephone and mobile phone. Every keypad is different, and yet, all of them have those "spirals" (see the image below) under the button or something similar. What I don't understand is how those "spirals" can put in contact…
Tripola
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10
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8 answers

Fix remote controller button contacts

On almost every remote controller the buttons stop reacting after a while, and you end up squeezing the remote out of his life while trying to switch the channel... I found some link where it explains how to "refresh" the contact-making surface on…
veljkoz
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2 answers

How do these modern power buttons on devices work

In the older days and still now we have buttons where one way is off and the other way is on, its mechanically built to connect or disconnect an electric path physically. On modern devices like laptops the power buttons work differently. Push once,…
quantum231
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2 answers

What kind of tactile switch is this?

I am trying to find some tactile switches similar (or even better, identical) to the ones shown. They are two stage, multi-way configuration. Depressing one click connects the common pin to pin 1, and depressing further (second click) connects the…
Mickrige McMahon
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8
votes
5 answers

Connecting push button to a controller pin

This problem is decades old but I do not see a direct answer to it on this site. I want the following: This circuit just allows to check the state of the button from inside the micro-controller. Nothing fancy. My questions: Is there anything…
Kirill Kobelev
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8
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2 answers

Button debounce ringing

I have a circuit where I am using a tactile switch to pull 3.3v down to ground and investigating debouncing the button. My relevant part of the circuit is The 100nF cap does work here my signal has ringing that operates in the undefined region…
Glenn Pierce
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4 answers

Does a switch need to be debounced when opened?

Suppose that an input on a microcontroller has a pullup resistor to 5V and a switch to ground (normally open) connected to it. I know that a switch should be debounced (in my case, in software) when closed, but is debouncing when a switch is opened…
Nate
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2 answers

Can multiple Schmitt triggers in series fully debounce a switch?

After dealing with software debouncing for a while, I find it takes a huge toll on the system, so I thought of initially making a hardware debouncer with one Schmitt trigger (74HC14), a capacitor, button and resistor as shown below from…
Mike -- No longer here
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6 answers

Differences between Interrupts and sampling for hardware button?

I have a hardware button I connected to an interrupt, but my problem is it bounces a bit, making the button press unreliable. I think a good deal of these issues would be solved by sampling in the main loop, but that just feels technically…
OneChillDude
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