Questions tagged [timer]
Circuit to generate a signal at a specific time after a trigger event. The timing can be defined by an RC time constant, or by clock pulses from an oscillator.
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555 circuit with high input and pulse adjustable output
I found a 555 timer that works with a pulsed input and gives an adjustable single pulse output. (see below).
I need the same circuit to work with a constant high input.
8ms input high
4ms output high
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Oneshot Circuit Design Improvement
Question is related to my this question here.
I want to trigger a buzzer for 500ms to 1sec whenever a switch is opened, answers on that question didn't produce satisfactory results so I came up with a ...
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One Shot buzzer
I want to drive a buzzer for 500 ms when reed switch opens, in simple schematics, when reed switch is closed it keeps Q1 pulled high (maybe I need a resistor too) but the problem with the design is ...
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STM32F407 ADC with timer trigger not working for some reason
For STM32F407 discovery board, I tried to establish ADC for measuring voltage at a point, using timer to trigger the ADC, every clock cycle.
Somehow I have missed something, because the timer clock is ...
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Delay with timers for a non-blocking delay
I need microsecond/millisecond delay in my project but I don't want to affect the process flow. I am using an STM32G4.
I am using a timer for microseconds delay.
This is the function:
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VGA signal on STM32 blackpill
I am trying to build a simple VGA video card using the STM32F401 Blackpill with max clock frequency of 84Mhz. I am aiming for a resolution of about 640x480 at 60hz. I tried using timers and PWM to ...
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How to boost the output voltage of my 555 timer design?
I'm fairly new to the world of electronic design. I'm building an astable 555 timer with the limitation being I can only drive it with a 3v coin cell battery (design has to be lightweight). I've been ...
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Replacing three-wire timed switch with a microcontroller
The building is surrounded by 6 lights and 4 buttons, 3 of which are illuminated.
Right now the circuit is managed by a Perry 1IT 1051. Here are the official schematics:
While I'm happy with the ...
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Opinion on Solution for minimal CPU use for STM32 based precision external ADC conversion timing
I have been working on a data acquisition system that requires fairly high sample rates given the resolution and dynamic range requirements. The front end performs well, but to avoid wasting large ...
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Is there an extremely simple circuit using 3V to have LED only on for 30 seconds?
Apologies in advance for this probably-grade-school-level question, but, of all the silly things, I want to make a light-up card that turns off after about 30 to 45 seconds. Fading would be a bonus ...
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STM32 timer shared input Pin (Encoder & PWM input modes)
Can I share the pin (PA0) between timers TIM2 & TIM5 (GPTIMs)?
Timers 2 and 5 can both use PA0 as an input, conveniently on ch1.
Is there any issue with configuring both of them to use PA0 as ch1 ...
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Wraping of counter in input capture
I am doing an input capture on STM32F401RE on TIM1 CH1, CH2, CH3, CH4.
On each channel when a capture happens the ccr1, ccr2, ccr3 and ccr4 will store the value according to the CNT register at that ...
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Simple timer circuit for LED
I have a hopefully simple question. I have 4.5 V battery-operated LED decoration that I want to turn on for 5 hours and turn off for 19, give or take an hour or so. Accuracy is not important.
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How to discharge timer capacitor quickly?
I have a simple timer in my circuit and I can't think of any solution to discharge C1 quickly:
simulate this circuit – Schematic created using CircuitLab
How can I discharge C1 in milliseconds ...
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which mode is 555 timer in this case
This particular timer is made to turn off the load, after KEY1 is pressed long enough. I am not sure if it is in astable or monostable mode.
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MSP430 delay using timer with polling condition
Need help with this code, it is not creating any delay.
I tried simulating this code in Proteus.
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Does the ESP32 WROOM-32 have an internal RTC?
I am working on an ESP32 WROOM-32 now. My purpose is to have it read some data every 15 minutes, in between the ESP32 goes to sleep mode.
Does the ESP32 have an internal RTC or timer? I searched on ...
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STM32H750B-DK ADC sample rate calculation
I am making an oscilloscope. I am using ADC with configuration like this:
And I am triggering my ADC with 1 ms (at least I think it is (was always confused on how to calculate its tick, so I just set ...
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STM32, how to create microseconds long custom pulses
In steady state the line (output) is high and we have to create pulses that are microseconds long and are low. It is going to be a custom sequence with different pulse lengths (for example the line ...
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Need 15 minute delay alarm [closed]
I need to use electronics to make a:
12v, ~60db, ~3second intermittent beep, ~15 minute delayed alarm, started by toggle switch, stopped by toggle switch.
Analog or digital, whichever is smaller.
Help ...
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ON few hours OFF few hours timer circuit
I am very new at this, but I am looking for a simple circuit (no microcomputer please) that will turn ON an LED for 4-5 hours, then turn OFF for 20 - 19 hours. Then it will automatically repeat this ...
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How to generate a single pulse circuit without using any MCU? [duplicate]
I have a 5V supply to turn my circuit on, and i need a one pulse circuit. The condition should be look like this;
When the circuit energized with 5 V it should go low after t1 time and it should stay ...
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Turn on LED for fix time when box is closed
I have a box which is used to put PCB in it when we are not using PCB. I want to turn on a UV blue LED for 1 minute when box is closed to cleanout the inside of box. I cant use limit switch as I don't ...
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Blue UV LED Timer Circuit
I have designed a PCB for mouth guard device and also its enclosure is ready in which PCB will be placed when its not in use. I want to use a UV blue light for UV sterilization inside the box. Now the ...
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Can these timer switches (relays) handle DC or will they arc?
I'm looking to add timer functionality to a 12V agricultural project. It's to turn a light and heat mat on and off at the appropriate times.
I was kicking around eBay and found a few timer switch ...
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Help with using monostable one-shot multivibrator for limited time
Trying to develop a circuit that would know how to output a square wave with a duty cycle that would be controllable, and the duration would be between half a second and a second.
Now I manage to make ...
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LMC555 delay off timer, M20 motor drive, updated
The goal is to either just give a signal to the motor with momentary switch, or turn on the toggle switch, let 3.7V motor run for a couple of seconds before 440uF is fully charged, after which voltage ...
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Connecting external clock source in PIC 18F4520
I require a delay of about 30 minutes using timers in PIC 18F4520. Using an internal crystal of 16 MHz, I would not be get desired delay from internal clock source.
I thought of using external crystal ...
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RC Timing Circuit with Power Control for Drone Flight Modes?
Recently, I came across an intriguing circuit design in AOE 3rd edition that inspired me to try it out. The idea is to design a simple circuit that activates an LED for precisely 60 seconds after a ...
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Why is this precharge circuit not functioning?
Although this question sounds basic but, I have been trying to implement this precharge circuit to safely turn on the inverter without overloading the system, however especially when I powered it on, ...
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"Delay Relay" or better "Ignore Relay" advice
I have an inherited project that is baffling me. (I am NOT an EE.)
TL;DR: need to ignore the signal voltage for the first 45 seconds (upon power-up), then allows all signal voltage there after.
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STM32 Timers - how to generate short pulses with long intervals between them?
I have STM32L451 and need to configure TIM3 to generate short pulses (duration is in the range of 1..10 us) and long time intervals (1 second) between the pulses on three PWM channels. The pulses in ...
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How does decreasing the clock speed for the timer (increasing the prescaler) raise the Minimum readable frequency?
Currently trying to get a STM32 F446RE to read frequencies of two signals that can change from 0 to 1kHz with granularity potentially as low as 0.001 Hz (Likely just gonna be 0.1 Hz) in real-time.
I ...
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555 Timer low duty cycle - wrong start point
I've built a low duty cycle 555 timer (astable) on a breadboard and on Multisim (here).
When the switch is closed, the LED turns on for about 1 sec (1.4 secs in Multisim) then turns off for 50 secs (...
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How to calculate system clock for ticks? I need to fire the timer every 60 secs (Attiny 404)
My timer initialisation
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555 Timer: Role of the Discharge Pin in A-Stable Mode
I am trying to build a 555 timer circuit and am stuck on understanding how exactly the discharge pin works. I am going off of these block diagram from the datasheet
RA, RB and C form an RC network in ...
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Why is there a spike in the output of this square wave oscillator I made using a 555 time with 50% duty cycle?
The wave form has a spike, what is causing it?
Would that spike create more harmonics than a waveform without the spike?
Scope shot of waveform:
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I need a recommendation on timer relays [closed]
Mechanical engineer being forced to put on an electrical engineer's hat...
Basically I have 2 proximity switches (https://www.mcmaster.com/7674k27) and I want to wire them in series with a push-button ...
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Need Timer circuit with Multiple Functions
Need a prototype following these requirements:
3 MICRO SWITCHES (Push to close)
1 LED
BUZZER
RESISTORS etc
2 digits 7 SEGMENT DISPLAY
1 DUAL TIMER IC (8 PINS)
25C08 EEPROM
STATES:
MAX TIME 10 SECS
...
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i8253 manual programming by direct signal input
I have a 8253 programmable interval timer and I want it to work in the Rate Generator (MODE 2). How can I achieve this using direct signal inputs to the chip?
I have attempted to write the control ...
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Bypassing a momentary switch
I am working on a project to make my motor starter completely automatic (turns on/off once the water level goes below or above the desired level) and I have gotten to the part where it automatically ...
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Capture/Compare Input Mode is not being triggered by PD12 on STM32F407 Discovery
I am trying to set a pin with capture/compare input mode and I will get the trigger from the PD12 pin which we have a green LED.
When I open the debugging mode, I see no change on the "timestamp&...
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STM32 timers works wrong in pair
A few weeks ago I ran into some strange timer behavior that I couldn't figure out.
Description:
I have a system which count signal from a wheel with tooth (for synchronization), based on input signal ...
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What does this diagram with two opposing arrows depict?
I have an astronomical timer relay that controls lights. Its user manual shows this diagram:
What do the opposing fat arrows (vertically aligned) indicate? How would one read them? Also, it seems ...
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STM32 TIM1 Input Interrupt Setting
I would like to get help with the input interrupt setting at TIM1. The inputs are PWM with different frequency. What I need is to get the rising edges and calculate the frequency of the input signals. ...
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Trigger timer from on and off not just a run on timer [duplicate]
I'm trying to build a small circuit that will run a fan for say 10 minutes, the timer would be triggered from an on / off pull switch.
The switch would trigger the timer to start on a change of state ...
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555 circuit question [closed]
I'm using a 555 IC in a timing circuit. If I tie the trigger low and power up the unit can I get a single 4-5 second pulse from the output? Will the unit reset when power is removed? Is anything ...
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555 IC 1 minute delay timer not working in simulator
I have a problem in Falstad that when making a 555 IC based signal delayer that should delay a power-off of a certain device, that the whole circuit behaves really weird and doesn't work as stated by ...
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Using Timer Interrupts Instead Of Delays in PIC Microcontroller
I have this task where I have to use timer interrupts intead of delays (for efficiency purposes) in this 7 segment display circuit with PIC18F4620.
Here is the circuit:
Display is common anode.
I ...
