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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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 (...
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2 votes
3 answers
154 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 ...
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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?
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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 ...
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Help with a simple debounce program on STM32

I'm trying to write a simple debounce program on an STM32F4. Code as follows: Initialization: ...
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1 answer
166 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 ...
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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 ...
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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 ...
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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.
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388 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 ...
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1 vote
2 answers
283 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 ...
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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 ...
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524 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 ...
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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 >= ...
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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 ...
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2 votes
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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 ...
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1 vote
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382 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 ...
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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. ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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2 votes
1 answer
118 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 ...
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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 ...
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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 ...
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1 vote
1 answer
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Weird RC time constants for possible debouncing

I am modifying a CTK-450 keyboard (manufactured by CASIO) into a MIDI controller. Going over the schematics, I found the way the keyboard CPU reads the keystates, which is rather simple. They are ...
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1 vote
1 answer
335 views

Not debouncing on a MIDI keyboard

I am modifying an old 90s keyboard (CTK-450 by CASIO) to make it a MIDI controller. I'm going for an Arduino that goes over the matrix layout of the keyboard. The issue I have is with debouncing. ...
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74HC14 for debouncing: output is too low with Vcc=3.3V

I'm trying to make a keypad for STM32 MCU using a 74HC14D.653 for debouncing. Datasheet says that it can be fed with 3.3V Vcc so I will not have to make level-shifting between it and MCU. The circuit ...
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Initial pluse from schmitt trigger switch debouncer

I want to use a momentary, normally open, SPST switch to act as a clock pulse on 16x2 character display. Of course, my switch has some bounce so I was looking at debouncing circuits and I always see ...
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Schmitt Trigger Level Translation from Encoder

This is my first time using an encoder as well as a Schmitt trigger. Typically, I would do debouncing in software, but I want a hardware solution for the sake of learning how to do so. The encoder I ...
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I couldnt' prevent button arc

Guys i have a circiut in below. There is a problem: i couldn't fix how to prevent this arc on my button. At 2. & 4. pins of button have 100nF and a resistor 1M to series these 2. and 4. pins. When ...
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Power Off and Capacitor Discharge

Could someone tell me where this diode (highlighted part) would be added and the orientation? https://www.maximintegrated.com/en/app-notes/index.mvp/id/287
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keypad debouncer configuration RC Value

I have keypad with for buttons and common signal connected to ground.. I noticed two configuration for debouncing as shown bellow.. Question: - Will the both configuration work correctly? when ...
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1 vote
1 answer
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Mitigate voltage drops when using a relay

Hi and thank you for reading my question. I have a small experimental solar panel setup which charges a deep-cycle battery using an MPPT converter. I would like to power some garage and garden lights ...
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3 votes
4 answers
547 views

Question about debouncing - delay of state change

I have a very simple project where I needed to debounce a button (in software). Logically, my thought process is: If the state's been stable for a while, and it changes, then immediately signal an ...
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20 votes
5 answers
6k views

Why can't I see bouncing of a switch on an oscilloscope?

I'm trying to view the bouncing of a simple switch on an oscilloscope. I have prepared a simple breadboard circuit (power → switch → resistor → ground). The problem is, it is displayed as a perfect ...
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How to debounce a low pulse switch for automotive lighting

Hoping you guys can give me a hand with some wiring that I can't quite figure out! Background: I'm trying to rewire a set of automotive lights - these are normally controlled by a computer but I'm ...
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1 answer
215 views

Debouncer with LED inside

How It's possible to add a LED to a line that it's debounced (switch) with an RC circuit. If I place 2 LED, one on ground and one on VCC to know button position. Will they remove my charge/discharge ...
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Driving transistors without using MCUs

I'm trying to drive transistors with just a push of a button without using a MCU. The circuit I drawn drives different transistor on every button push and resets back. First part is a debounce circuit ...
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4 answers
2k views

How do you pick component values for a debouncing filter?

I bought an incremental/quadrature rotary encoder for a project I'm working on. The specs: https://www.bourns.com/docs/Product-Datasheets/PEC12R.pdf They provide a diagram of a suggested filter ...
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Really occasional malfunction of the Schmitt-trigger input

I'm using some Schmitt-trigger inputs for debouncing the interrupt problems. Referring to above circuit, the circuit has a RC circuit and the output of the RC circuit goes to the Schmitt-trigger IC(...
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2 answers
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Non-shorting Rotary Switch "dead" Time

Is there a nominal dead time for rotary switches? Obviously all switches are different, so this value will not be precise. For making a reasonable situation, let us assume that a detent style switch ...
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