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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5answers
348 views

MUX input debouncing?

I am using a CP2103 to interface with a simple 74HC4051 MUX. I want to use 3 of the I/O ports on the CP2103 to control the input pins of the MUX. The 4th I/O port is being used for something else. The ...
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1answer
465 views

RC debouncer circuit does not work

I tried two circuits below, none of them seems to be working (I used 74LS04 and 74LS00), the output doesn't change when I press the switch. I found that the voltage at point "A" doesn't drop below 0....
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4answers
869 views

A question about a debouncing circuit

I was reading a tutorial on debouncing the outputs of a rotary-encoder which are read by a micro-controller. Below is the circuit given: The writer of the tutorial claims the following: "In the ...
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1answer
288 views

What is masking-time and chattering in rotary encoders?

In the datasheet of these encoders there is always a chapter mentioning masking-time and chattering. I couldn't find any tutorial on this. What are these definitions about?
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2answers
304 views

Is debounce necessary when detecting voltage on a relay switched lamp?

I'll be using an Arduino to "read" the parking light wire on a car. I was wondering if debounce is necessary here? I want to think that the factory bulb will act as a debounce to smoothen out the ...
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3answers
454 views

Should I consider debouncing my push button?

Considering a +5V battery source, I have a set of input switches. These switches are push buttons which stay closed upon clicking and open upon clicking again. One side of a switch is connected to ...
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1answer
385 views

How long should I drive the coil of a latching relay?

I have inherited a project that uses HFD2/005-S-L1-D single coil latching relays. The datasheet is here. It lists 4 parameters which may be what I want: Operate time: 4.5ms Release time: 3.5ms Set ...
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2answers
1k views

debounce state machine graph

I need to make the graph for a state machine that debounces an input signal, maintaining the current up/low input signal for a certain time, and to calculate this time im using a counter. I am having ...
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1answer
651 views

Need help for a Dflop implementation in LTspice

I'm trying to implement an analog debouncing filter which uses a 555 timer and a D-flop. Here is the recommended circuit. But when I simulate this in LTspice as below, the output is 1V constant: (...
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1answer
2k views

How to add bouncing to a switch in LTspice?

Is it possible to add bouncing for a switch in LTspice? Below is a reed relay simulated in LTspice. I can set the on and off resistances but is there a workaround to create bouncing as well? With no ...
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0answers
535 views

Debouncing and hysteresis questions about a Schmitt trigger circuit

Above is a switching sensor which outputs ON OFF pulses by the 33k pull-down resistor. V2 and R_SW models the switching. The sensor output is needed to be measured between 1Hz upto 150Hz. I'm planning ...
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2answers
1k views

Push button debouncing circuit without extra IC? Possibly RC based?

I have a push button that I would like to debounce. I only care about the first rising edge of the signal which is connected to an Arduino's GPIO. After reading on the web about hardware debouncing, I ...
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1answer
348 views

Can I achieve debounce using a zener diode?

I am interfacing a 4x3 keypad with LPC1778 using GPIO pins. These pins are 5V tolerant. Can I use zener diodes in the debouncing circuit? Can I use zener diodes like this?
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1answer
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debounce - capacitor short circuit

Often debouncing circuits are done like this : simulate this circuit – Schematic created using CircuitLab In this case, when switch is closed, C1 discharges in its internal series resistance, ...
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1answer
1k views

Interfacing 12V logic with 5V circuitry

I'm trying to build a simple circuit to control a church lampadary for an escape room game. I don't know if you've seen these but they're fairly common in catholic churches where I live: You input ...
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2answers
732 views

How does this simple contact debouncing circuit work?

I made a contact debouncing circuit using a capacitor. The main idea was to charge the capacitor, so that the bouncing on the signal would be "smoothed out". It works, but It's been a while since I ...
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3answers
2k views

Switch Debounce Topology for Rotary Encoder [duplicate]

I'm looking to debounce the output of a rotary encoder I'm using as a switch to ground with a pull-up. Looking online I saw the debouncing circuit in Figure 2 and read about it here. However, I also ...
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3answers
2k views

Hardware buttons debouncing crosstalk

I'm using a hardware-based debouncing circuit to trigger an interrupt on a Particle Photon development board. I use a similar circuit with two buttons: Sometimes when a button is pressed, the ...
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1answer
109 views

Automatic and manual clock managing. Errors with ring counter but not with 4-bit counter

I'm building an 8 bit computer and I've just developed the clock. I used a NE555 (datasheet) with some other integrated (74 series) to manage it. The operator could stop signal from 555 (with a ...
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1answer
164 views

Toggle switch as momentary with debounce

I have been trying to do the following: When a toggle switch is flipped down, the pic I'm using (16F1503) sends a pulse and turns on a led, when it is flipped up sends the same pulse and turns off the ...
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4answers
508 views

Button debouncing not working [closed]

I want to toggle a led with a push button and an ATMega16a but for some reason the toggle behavior seems a bit randomly. ...
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2answers
604 views

Resetting a microcontroller with a button connected to Vcc

I would like to have a way to reset my PIC by removing power from the chip. My hacker self thinks that the simplest way would be to add a resistor between the output of my LDO and Vcc on the PIC, and ...
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1answer
192 views

Microswitch debouce circuit plus high impedance points - case study

I have a circuit where 3.3V are used for MCU and other peripherals, but microswitches are running on 12V. In the first version, microswitch was connected to the base via base resistor of a BJT. What I ...
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1answer
860 views

How to write a counter in verilog for debouncing an input?

I am trying to write a module counter to debounce a input coming from mechanical buttons. The module should be controlled by the 4x4 matrix button module when to start or stop debonce. This is my ...
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0answers
442 views

555 to debounce comparator output for PIR circuit

I'm trying to create a circuit that takes an input from a PIR and outputs a high signal when movement is detected. My circuit currently looks like the schematic below (VCC is 5V). The circuit works ...
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2answers
262 views

Debouncing/Stabilizing power supply rocker switch?

I'm having trouble with the power signal out of my Rocker Switch (https://www.sparkfun.com/products/8837 for reference). My PIC18F4550 + 16x2 character LCD screen project was running fine until I ...
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3answers
748 views

Where to place debouncing circuit for remote mounted buttons and rotary encoders

I have an application where a push button and mechanical grey-code rotary encoder(user inputs) need to mounted away from main pcb. 24" - 48" away. This is for space and packaging reasons. Is it OK to ...
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1answer
677 views

Debouncing a TTL Photodiode Detector

I am designing a photodiode sensor that will sit on a computer monitor and will output a +5V TTL signal if the screen is displaying and image and a 0V signal if the screen is not. The prototype ...
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1answer
685 views

RC debounce mosfet gate

I am trying to debounce a switch that controls the gate of a mosfet. Will the circuit below work, or do I need to re-arrange some of the parts? *The circle thing should have been drawn as a mosfet.
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1answer
2k views

How is debounce achieved in (EM) relay?

I was reading theory that: A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-...
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1answer
224 views

USB and button power on solution

I've a circuit that have one input pin that should go LOW if one of two conditions is accomplished: USB is connected; Button OR Switch is pressed/slided; If USB is connected Button or Switch is ...
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1answer
405 views

Timing diagram of circuit involving switch debouncing

I have a push button switch (single-pole double throw) connected to a latch as follows... I was thinking about the timing diagram of the circuit above (above image is the default state of the circuit ...
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1answer
251 views

In RFID, are there tag modules that give the user a choice of different outputs?

I look for an RFID tag that gives you the option to 'choose the output'. For example, you want to choose an RFID-output from a list of X possible outputs using a multi-directional switch with X ...
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4answers
15k views

Understanding interrupts and software button debounce

I'm quite new to AVR programming (avr-gcc). To react on button-press, I am using a PCINT ISR with the internal pull-up resistor enabled like this: ...
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1answer
143 views

Where should I include the instantiation in top module(counter)

I am doing a counter module in Basys-2 board.This is my instantiation of the debouncing circuit ...
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1answer
2k views

debouncing pushbuttons in verilog

I have two circuits which I have designed using verilog.One is Counter circuit and other is the debouncing pushbutton circuit.but I dont now how to instantiate a model so that the pushbutton circuit ...
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1answer
544 views

RC low pass filter PCB layout limitation

I have an RC low pass filter for debouncing a GPIO pin. Do I have to place the resistor and the capacitor close to each other? Currently the capacitor is near the GPIO pin, and the resistor can be ...
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3answers
1k views

Can I debounce after a shift register?

I am rewiring a cheap old organ for digital and want to use shift registers to read all the keys. Is it possible to debounce the keys after the shift registers, or do I need to do it before? Either ...
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1answer
3k views

Contact Bounce - Simple Debounce RC Circuit Question

I got this circuit from an example. simulate this circuit – Schematic created using CircuitLab What kind of circuit is this? I know its an RC circuit and I also know that its designed to be a ...
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2answers
245 views

Non-TTL debouncing

This is probably simple, but I'm not an ee. A closet with 4 doors, each has a normally-closed pushbutton connected to 5V source on one end and (to the same) 5V relay which controls the 220V (AC) of ...
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4answers
3k views

Which diode to use on my RC switch debounce circuit?

I am choosing parts to build an analog RC switch debounce circuit. I plan to implement the circuit described here: http://www.ganssle.com/debouncing-pt2.htm (see "An RC Debouncer"). RC debouncer ...
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1answer
656 views

I am looking to isolate an inverter when power from a generator is applied- debounce relay?

I have tried to find specific info on this scenario with no luck The situation is this; Off grid power system 12v battery store runs 12v lights etc. and an inverter for things difficult to run or ...
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3answers
3k views

Is this a good way to debounce a switch?

There are plenty of debouncing circuits on the internet, but I couldn't really find one that fitted my needs / available parts, so I came up with my own, from what I had. There's nothing special about ...
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2answers
664 views

arduino due build-in interrupt debouncing

According to the SAM3X handbook it can do debouncing of interrupts "automatically", how would I enable that on an arduino due? The doc http://www.atmel.com/Images/doc11057.pdf states something about ...
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499 views

To Remove Debounce from MicroJoystick installed on LogicStart MegaWing (FPGA) and read input correctly

I am working on an FPGA board and coding in Verilog. I am trying to use the MicroJoystick installed on LogicStartMegaWing, the shield with Papilio-One 500k (my FPGA board). I have to do simple tasks ...
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1answer
824 views

RC Schmitt Trigger Debouncing - Cap discharged but there is a voltage across it still

As you can see in the image, I'm running the example given in here where I would debounce the limit switch. I'm running the SN7414 with the given resistors in the diagram. The problem here is that ...
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1answer
1k views

State switches in FSM

I have a simple board with 6 buttons, consisting of 3 columns and 2 rows I would like to detect the pressed button. My code below works with this fsm: ...
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2answers
1k views

Do I have to debounce MCU reset pin?

I have it only tied to switch via a pull-up resistor on a pic. I'd like to not perform any hardware debouncing to save on costs, but I'm wondering if this could lead to a higher fail rate of ...
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2answers
279 views

Xbee-Arduino serial input (outliers problem)

I have an Xbee configured as receiver and Arduino (standalone w/ atmega328p chip) connected together. The RSSI pin of the Xbee is connected to one of the Arduino Board PWM pin. I used the PulseIn to ...
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3answers
702 views

Debouncing by ignoring data?

All of the software debouncing routines I've seen involve waiting until some number of sequential reads of a signal return 0 or 1. That makes sense, of course. But it means there's an inevitable ...