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Questions tagged [debounce]

When a mechanical switch closes it's contacts typically do not close "cleanly" and tend to bounce or chatter. This rapidly switching signal could be misread in certain situations so it is usual to attempt to reduce this bouncing to ensure a clean switch detection. the danger is that if the switch is not de-bounced you can detect multiple events from one opening or closing. Can be accomplished using analog circuits or digital circuits.

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Issues with switch debouncing

I am having some issues with debouncing a switch with an RC filter and 74HC14 Schmitt-trigger inverter IC. I am using a standard circuit that is linked in the datasheet. The circuit in question here ...
Zackery Fleming's user avatar
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STUSB4500: Contact Ground Issue

I'm working with the STUSB4500 for USB PD Sink. My PD circuit is the same as the Sparkfun Power Delivery USB-C board, and everything works well, except for the fact that the ground is super sensitive ...
Emerson's user avatar
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How do I flash LED with signal from 555 timer ONLY when button is pressed?

I am trying to make a circuit in which an LED is off until a button is pressed, and then it flashes with a 1Hz signal from a 555 timer. Currently, its default state is flashing with 1Hz and when the ...
Chandler Thornton's user avatar
5 votes
3 answers
877 views

How does this debounce circuit (from Arduino Portenta Edge Control) works?

I stumbled upon this part of the schematic (page 2) of the Arduino Portenta Edge Control (shown below), which – in my eyes — seems to be a debounce circuit, but more complex than the one shown in this ...
Jerry Magnin's user avatar
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1 answer
45 views

LS19-S, what to do with unused inputs>

I am using a LS19-s switch debouncing IC, and the datasheet does not specify what to do with unused inputs. I know for CMOS chips it standard to ground unused inputs and for TTL chips the unused ...
Zackery Fleming's user avatar
4 votes
3 answers
2k views

Should I debounce everything?

I am a newbie in electrical engineering and recently learnt about debouncing. While it's obvious why I should debounce a push button that is connected to a microcontroller, I'm wondering why there are ...
Yurii A's user avatar
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107 views

Triggering a signal on the falling edge of an input, and not re-triggering when it stays low

I have a 555 in monostable mode that will generate a signal from the transition to low from one of it's inputs (as they do). The issue I have is that the trigger will out last the signal by an order ...
QueueHammer's user avatar
0 votes
2 answers
78 views

Should I buffer my switch button input?

I have external switch with 24v/open circuit. I think that I only need voltage divider and drive the FPGA input, but something feels weird for me, maybe I need some capacitor for noise? maybe some ...
Knowledge's user avatar
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2 answers
236 views

Is debouncing necessary for a power switch?

A few months ago I asked for help designing a circuit for powering on a microcontroller using a tact switch, and I finally just prototyped the circuit that @Jonathan-S. suggested. It works great. ...
Andrew Mowry's user avatar
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1 answer
30 views

Debounce switches on car stereo bluetooth receiver

I have retrofitted a Bluetooth receiver to an old car stereo, replacing the cassette. Although this generally works fine, there has been some issues with the three play-pause/ff/rw momentary switches ...
Jungle Jim's user avatar
1 vote
2 answers
514 views

Why does my switch debouncing circuit still result in occasional false presses?

I have an issue where my switch debouncing implementation isn't working. I have a custom STM32 board with switches connected to an interrupt pin on the STM32. The pin is configured to be interrupt on ...
ChrisD91's user avatar
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3 votes
1 answer
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How to debounce a normally closed switch?

The 74LS192 IC's up count (pin 5) needs a logic 0 in order to count up. I'm trying to debounce the switch so that it doesn't give multiple inputs to the IC. I've tried this circuit that is used for ...
Justine Ogapong's user avatar
0 votes
2 answers
173 views

Is this a functional debouncing circuit?

Is there anything wrong with this debouncing circuit, aside from the fact that it can be made with a single Schmitt trigger and a capacitor that is charged when the button is not pressed?
Andrealphus's user avatar
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0 answers
83 views

Edge detection circuit causing multiple inputs

I am trying to build a shift register using only 2 inputs - a button to enter high, and a button to enter low. Since I'm not using a separate button for the clock, I need to make an edge detection ...
alejanndro's user avatar
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985 views

How to connect an EC11E rotary encoder to a microcontroller?

I'm connecting a EC11E rotary encoder to a Adafruit Feather 32u4 Bluefruit LE. The EC11 has 5 pins: 2 for the switch, and 2 for the knob. Connecting the encoder itself would be easy, but I'm having a ...
kid's user avatar
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1 answer
722 views

Buttons that do not bounce or scopes that pretend to be 100 MHz but actually aren't?

I have bought single push buttons in India for 1 rupee a piece, that's a penny or so. They are seemingly very basic (you can see them around here other question). I might follow up here with more ...
Gunther Schadow's user avatar
1 vote
1 answer
281 views

STM32 Nucleo board, "crosstalk" between switch buttons

There are 3 switch buttons on a regular solderless breadboard each following this diagram: Upon pressing any of the buttons, I am getting spurious breakpoint hits inside the ISRs for the other two as ...
kellogs's user avatar
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SPDT switch with opposite polarity and bounce eliminator/debouncer with Schmitt Trigger

I had a question in my electronics course homework pertaining to eliminating the bounce from a SPDT switch with a Schmitt trigger. The switch has two inputs with opposite polarity. I've looked online ...
imthegman55's user avatar
0 votes
1 answer
620 views

Syntax error Begin statement HDL 9-806

I have an error in the form of HDL 9-806 on the begin statement. The code below is a button based sequence detector an addition LED flash when sequence is correct with a debouncer to stop multiple ...
S G's user avatar
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0 votes
1 answer
308 views

Debounce and reduce voltage on a 24V switch

I am familiar with the debounce of a switch connected to GND and swinging between the same voltage levels of the logics: simulate this circuit – Schematic created using CircuitLab But I need a ...
Marco's user avatar
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1 vote
2 answers
2k views

How does an SR latch prevent switch bouncing?

I saw this debounce circuit here and they said that when the switche bounces from NC - NO - NC, the output 0 of the NAND gate g1 locks the output of g2 to 1 and the output still stays the same. ...
wd violet's user avatar
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1 vote
2 answers
616 views

Reducing relay contact chatter from bimetallic switch control (AC coil, mains voltage)

I am looking for a few techniques to reduce contact chatter in a relay controlled by a 120 VAC voltage signal. The circuit uses a bimetallic thermal switch to turn a resistive heating element on and ...
higrafey's user avatar
  • 343
5 votes
5 answers
4k views

Does this mechanical switch really have no bounce?

I'm prototyping with a bunch of no name mechanical button mini-switches and SAM D21 microcontroller (Adafruit Feather M0). The switch is connected directly between the ground and the input pin #19 (...
Paul Jurczak's user avatar
2 votes
3 answers
467 views

Does placement of resistor and cap in a button debouncing circuit make any noticeable difference?

I'm making a prototype PCB with an STM32 chip and I want a couple of tactile switches for various reasons. I have followed the button debouncing circuit as done on the dev board: My PCB design is ...
ChrisD91's user avatar
  • 707
2 votes
1 answer
91 views

Simulating realistic button presses

I need to simulate realistic button presses that include bounce patterns..but digitally with something like an FPGA to test my debouncing code. How do I generate those noises?
Baba Yaga's user avatar
2 votes
2 answers
576 views

RC Debounce: Is there a benefit to placing the capacitor in parallel with the switch?

I've always seen RC debounce circuits drawn wire the capacitor tied to the same potential as the switch. E.g. if the switch is high-side, the cap is high-side if the switch is low-side, the cap is ...
Kieran's user avatar
  • 21
2 votes
1 answer
4k views

Help with a simple debounce program on STM32

I'm trying to write a simple debounce program on an STM32F4. Code as follows: Initialization: ...
Joshua John's user avatar
1 vote
1 answer
665 views

MSP430 Prevent Bouncing

I'm currently working on a homework that does: the first press to the button at P1.1 opens the LED at P1.0, the second press to the same button blinks the LED and the third press closes the LED. I ...
Efe's user avatar
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1 vote
3 answers
360 views

How to RC debounce toggle switch?

I'm trying to understand if the following debounce circuit works. I want a logical HIGH when the switch is closed and I want to smooth over bounces by means of a low-pass filter. When the switch is ...
htor's user avatar
  • 200
0 votes
1 answer
453 views

Combining interrupts and debouncing on a keypad

I would like to interrupt a program when a key is pressed on a keypad, and figure out which key has been pressed. I do not care much for ghosting effects, this is supposed to be operated with one ...
user42875's user avatar
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-1 votes
1 answer
3k views

using Schmitt trigger to debounce a switch [closed]

How can a Schmitt trigger be used to debounce a switch? please try to explain it with pictures as well.
NoobCoder's user avatar
3 votes
5 answers
1k views

How can I debounce a switch on both positive and negative-going edges?

I would like to connect a mechanical switch to an interrupt pin on an Arduino Uno processor where the interrupt is configured for CHANGE interrupts (i.e., triggers on either a positive-going or ...
Jim Luby's user avatar
1 vote
2 answers
693 views

Debounce slide switches in verilog?

I just created my first FPGA project. I created a small FPGA PCB with some slide switches to input values to the FPGA. Sadly, I did not debounce them properly with hardware, as you can see in these ...
F_Schmidt's user avatar
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4 votes
3 answers
781 views

Minimizing signal delay when debouncing

I have a mechanical switch that I'd like to use as a signal source for a digital input of a microcontroller. The switch is normally closed, and I'd like to detect the switch being opened as quickly as ...
Florian Ragwitz's user avatar
-1 votes
3 answers
1k views

What's the best way to debounce a slider switch?

I'm really struggling with a VHDL implementation of a debouncing circuit for 2-position slider switches.I had initially planned to use an SR latch to do this but couldn't figure out how to make it ...
MendelumS's user avatar
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0 votes
2 answers
771 views

I need help debouncing a push button

I am trying to debounce a button. Here is my result so far after placing a 1uF ceramic capacitor in parallel with the button: This should work as an input to my Arduino 5V since it has High: U >= ...
Andy's user avatar
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3 votes
1 answer
221 views

Clarifying an article on switch debouncing - something about leakage current causing trouble

I recently read this article on switch debouncing: A Guide to Debouncing - Part 2, or, How to Debounce a Contact in Two Easy Pages, by Jack Ganssle. The article is on choosing the correct resistor and ...
Jithin Vap's user avatar
2 votes
2 answers
2k views

Suitable RC debouncing circuit?

I'm trying to implement an RC debouncing circuit into a design I'm currently working on, and I have been using this PDF as a reference: https://my.eng.utah.edu/%7Ecs5780/debouncing.pdf In the PDF, the ...
transienttoast's user avatar
1 vote
2 answers
1k views

Hardware debouncing using 74LS14 - inverter input does not drop below 800 mV

I just recently started dabbling with electronics, so probably I just made some beginner's mistake. Here's my problem: I want to debounce a switch in hardware. During my internet research, I found ...
pczora's user avatar
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6 votes
3 answers
1k views

Is this an acceptable circuit for debouncing a Raspberrry Pi input pin?

I am trying to design a circuit to debounce an input switch on a Raspberry Pi. The switch is for a doorbell, so it doesn't need to register multiple valid presses that are close together in time. ...
Alex's user avatar
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1 vote
3 answers
666 views

Why have extra resistor in switch debounce circuit

I am using a Laird BL654 module in my project, and using the dev board schematic to help me. On the reset switch they have an external pull-up of 10k (R112) (in addition to the internal one on the ...
bgarrood's user avatar
  • 221
0 votes
1 answer
54 views

Attiny13 odd behaviour sometimes

I'm programming ATTiny13's to use on a custom PCB and have noticed an odd behaviour at times. My ATTiny is connected to an Arduino Nano as per the diagram shown here, so pretty standard. I then use ...
Marcos Placona's user avatar
1 vote
3 answers
5k views

Does EC11 Incremental Encoder need hardware debouncing and VCC for encoder?

I'm implementing an EC11E rotary encoder which has 3 pins + 2 pins for a switch. It seems like most of the projects I've seen online wire A/B and GND to the microcontroller, which to me, makes sense. ...
Felix Jen's user avatar
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-4 votes
4 answers
847 views

Push button de-bouncing, nothing works. [Please, only answer if you have actually done it (recently or often enough) to know for sure!]

I see a lot of text on the internet and here telling us how to de-bounce a switch, in my case a push button. But I have tried all these circuits and I find that nothing other than a 555 monostable ...
Gunther Schadow's user avatar
0 votes
2 answers
1k views

WEMOS D1 R1 Interrupt repeats continuously, when triggered, Is it bouncing? How to fix it?

I am having such a nightmare to make it work, I am using a WEMOS D1R1 to handle the movement of an encoder via external interrupts. Instead if detecting the edge (L to H), it detects the status, so ...
tgtech's user avatar
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1 vote
2 answers
1k views

How would you all implement a simple delay of a signal?

I am a console game developer by profession, and has no formal education on electronics / electrical engineering. In gaming lingo, a 'noob' if you will, at it. And yet I have a new found passion for ...
Jithin Vap's user avatar
8 votes
2 answers
1k views

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 ...
Glenn Pierce's user avatar
2 votes
1 answer
261 views

single stepping TS68000 microprocessor

I recently got TS68000 microprocessor. My final goal is to build a simple computer based on that CPU. For now I am trying to find a way to single step it. I found schematic below by ...
aberforth's user avatar
0 votes
1 answer
371 views

improving this debouncing circuit

I'm using the circuit to debounce a momentary push button switch (and drive a relay). Probably the switch is not that great (it is a stomp switch) so I got a lot of bouncing, and the end result is not ...
Dimitri Petrucci's user avatar
0 votes
1 answer
99 views

Power supply switch-off characteristics

At a previous employer, we had an issue where some of our power supplies would brown-out when turned off, and this destroyed some hardware. By 'brown-out' I mean they acted like there was a capacitor ...
Ethan Reesor's user avatar