Questions tagged [timer]

Circuit to generate a signal 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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32 views

How to run 3 motors of cold room sequetntielly each hour [closed]

I want to sequentially run 3 motors: the first motor run for 1 hour, the second for one hour and the third for 1 hour, again the first motor for one hour and so on. I serched for a time relay (only ...
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1answer
34 views

How does this specific boost converter work?

So I found this Geiger counter at https://mightyohm.com/blog/products/geiger-counter/. You can also find the detailed electronic schematics there. I tried to figure out how this apparatus works, but I'...
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27 views

I have two NE555 timer with an outputs a High PWM and Low PWM. How do i turn on one timer and then the other

I am currently working on a project that requires a low PWM to an esc (electronic speed controller) at the beginning for three second. and then I can change the PWM after that. I have two NE555 timer; ...
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1answer
101 views
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Configuring Atmega32 timer using the oscillator without prescaling gives wrong delay time

I am using AVR atmega32 microcontroller. The code below is supposed to toggle the LED connected to PORTD. The frequency of the oscillator connected to the ...
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2answers
85 views

Super low duty cycle circuit

I am looking for a way to recharge some glow in the dark paint in a way that isn't noticeable to others. My idea is to use a very fast pulse of light from a bunch of UV LEDs every few seconds, but ...
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2answers
61 views

Context Switch in C in 32-Bit MCU

I am trying to understand the concept of 'Context switch' in reference to C-language and 32-bit MCUs. For example if I am programming STM32F407 MCU in C-language using STM32CubeIDE and I want to ...
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1answer
15 views

STM8 alarm firing shortly after resetting time

I'm using an STM8L151F3 with the SPL, compiled with SDCC. I'm trying to generate an alarm interrupt after n seconds, then another after m seconds. To do that, I reset the time to 0, then set the alarm ...
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26 views

Will this “off delay” circuit work if a continuous trigger is applied to pin 2?

This is an off delay circuit using a 555 timer. I want to know if this can be used even if the trigger signal is continuous. If, not what modification is needed?
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55 views

Can't seem to properly generate a delay via timer

So I am trying to create a delay using a timer but doesn't seem like it's working as expected. With a clock of 16MHz and a prescaler of 1, it should take 10us to reach a count of 160 (unless I did ...
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6answers
131 views

Generating a delay on the order of microseconds (timer vs HAL_Delay())

So I am using an nRF24 radio module and I probably need a 10us delay after enabling chip select. But the thing is I can't use HAL_Delay() since the least it ...
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2answers
76 views

DIY Pierce Oscillator not working

I'm building a simple pierce oscillator for fun and trying to read the frequency using an arduino uno and the freqcount.h library (I don't have an oscilloscope). However, I'm consistently getting a ...
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0answers
58 views

STM32 TIM2 changing prescaler in IRQ handler works strangely

I am trying to change a prescaler in the timer interrupt handler, and I expected the new value would become active for the very next timer delay. I mean that after the handler exits, the timer will ...
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1answer
25 views

Advice on setting up sensor switch

Hi I would like to fit a (motion sensor/IR sensor) sensor switch to a machine in my catering van. The machine is a 12v machine. I would like to start the machine using the sensor switch and would like ...
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1answer
36 views

Bug and Best Practices for Interrupt Handling/Organization

I've read a few documents on best practices for interrupt handling and thought I was doing things correctly, ensuring the variable set in the ISR was declared volatile. In my code the interrupt ...
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1answer
59 views

I want to add more time to this relay delay

The maximum is 3 seconds, I want it to be 5 minutes or even 10 minutes if possible. What should I do in terms of changing capacitors or resistors etc? Thamk you. I tried to reverse engineer it,This is ...
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1answer
89 views

Want to replace push-button with IR receiver

In the diagram below I want to replace that push-button switch Sw1 with IR receiver, I tried a lot with different combination with IR receiver and tried with transistor but I failed, so, please how ...
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1answer
66 views

Does dividing a clock increase its jitter?

I want to have my microcontroller and ADC using a clock derived from the same source in an effort to avoid intermodulation effects. All clocks are under 50 MHz. The maximum SNR out of an ADC is ...
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1answer
63 views

Generate a fixed number of pulses on the STM32F4 PWM

I am trying to control a servo motor (link). It is a brushless DC motor with an interface similar to a stepper motor. The motor rotates for a defined distance based on the number of pulses it ...
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1answer
104 views

What type of capacitor do i need for this delay?

I installed a set of LED RGB foot-well lights on my truck. When they turned on, they have a small half second glitch before staying constant. I believe that this is because the LED RGB controller ...
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1answer
34 views

Required timer count for a number of same frequency different duty cycle PWM signal

Ok, it may look a bit confusing. I am specifically talking about STM32 MCUs, or even more specific, STM32F103C8T6. I did some amount of reading, but could not find the answer to this. Let's say I ...
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1answer
53 views

555 timer question

R1=500k variable resistance R2= 10k when the timer's operation time is 5sec, R1 86.7k What is the operation time when 4V is applied to 5(red point)? im student, so I would very appreciate it if you ...
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3answers
77 views

Solar powered mini water pump: how to turn it on/off automatically

I have acquired a mini water pump (5V 1.0A) and several solar panels (each: 5V 200mA). What I try to achieve is to pump water from a container above a vertical hydroponic system and let it flow down ...
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1answer
43 views

PWM Three Phases with PIC

I am trying to program a PIC18F4550 to control a 3 Phase BLDC motor. I have doubts about how to make the program, since I have seen many examples that what they do is use the TIMER to generate the 3 ...
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40 views

wiring for my timer switch

I'm trying to wire as per the following wiring diagram. I completed wiring as below, and timer is switching on, but at the programmed time, light is not switching on, anything wrong with wiring. See ...
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2answers
110 views

Little circuit to turn off start&stop of my car

I bought a new car with s&s and, every time I turn the car on, s&s automatically turns on. There is a button to turn it off manually, but I want it automatically off. I was thinking about ...
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Cadence simulation graph versus time

please do not know if there is a functionality in CADENCE in the graphs show differences in the times between them (make an average of two values). Regarding the delay of two waves [Automatically in ...
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2answers
58 views

small inexpensive battery powerable component for daily timer circuit with LED and button

I want to make a small "visual alarm" device that turns on a LED every day at a time (e.g. 17:00) and turns the LED off on button press or (if no button was pressed) at a later time (e.g. 22:00). I ...
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2answers
97 views

Most efficient delay circuit

I am currently trying to design a basic time delay circuit. The circuit's goal is to switch on a BLE beacon (requires 1.8V-3.6V at 1mA) for 3-5 seconds and then switch it off again. My first option ...
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1answer
33 views

Off-delay timer with only a relay and an on-delay timer

I'm trying to run two fans when there is a call for heat but I want fan 2 to shut off a few minutes later. I don't have an off delay timer however I do have an on-delay timer and a relay. I know it ...
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62 views

simple way to get a single pulse using a cd4060?

Wondering what what be the easiest (least component count/passives only) of getting a single pulse from a CD4060? Looking for a delay of about 10 seconds generating a single pulse of about .25 second ...
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56 views

What is the difference between TIMx_IRQHandler and HAL_TIM_PeriodElapsedCallback function?

I am a beginner, I am using the stm32F103 interrupt function TIM1_IRQHandler function to count, but HAL_TIM_PerodElapsedCallback can also achieve accurate counting, which one should I choose to use? ...
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2answers
257 views

Generation of a shorter pulse based on trigger (similar to 555 as monostable)

I need to create a shorter pulse based on a trigger signal. Trigger signal has a duration between 1 to 10 ms and the desired output should be 0.5 ms. To do the opposite (longer output pulse than ...
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2answers
33 views

SR Latch output pin biases state of the logic gate under special circumstance

I am having a really hard time putting my question in the right words, but I will try my best. So I am working with an MCU (EFM32TG11) that features a bootloader with pin activation. To make the ...
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1answer
72 views

Appliance countdown timer using current transformer and 555 timers

I am trying to design a timer for a 220V AC appliance (a coffee grinder); my goal is to learn about analog circuit design, I know how do this easily with an Arduino or equivalent. I am starting from ...
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30 views

ADC Triggering with TIM3 TRGO running in PWM mode in STM32F446

I have been trying to trigger an ADC using TIM6 with TRGO signal in STM32F446RE board. I am unable to do it. I have used CubeMX initialization and have been trying to use the HAL libraries for ...
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37 views

STM32 timer with DWT problem

I'm using STM32F103.I'm trying to make a code that run every second. here is the code ...
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1answer
54 views

RC Timer Circuit (fundamental) Misunderstanding

I'm working through Electronics for Dummies book and I'm stumped with the RC Timer example. See the diagram below. I believe I understand the idea of it taking a period of time for the capacitor to ...
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1answer
63 views

How to achieve an interrupt frequency of 100 kHz on SAM E70?

Setup: ATMEL Studio 7, ASF3.47.0, SAME70 XPlained eval board. In the minimum working example shown below, I use the onboard LED for visualizing if the timer and interrupt enabling have executed. <...
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41 views

Hardfault or otherwise wonky timer behaviour - STM32 Cortex M7

I am using the line marked by the arrow in the code below as such and it works fine. If I uncomment // HAL_TIM_IRQHandler(&htim2); there is one hit on the ...
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1answer
107 views

How to build a timer/delay relay

I want to build timer or delay relay, so that after I remove 12V DC from it, it keeps pulling for 1 second, and then releases. What are the components that I need to add to a 12VDC relay?
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3answers
143 views

How does one get ticks of a clock from an atomic clock's microwave signal?

I understand that in an atomic clock there is a microwave signal that is locked to the frequency of the atomic rotation. However, if one wants to extract time ticks from the microwave signal (shown ...
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2answers
55 views

Staircase Timer with On/Off switches

I want to build a circuit for my home. The setup is as follows: I've got a circuit in my house, I can turn my lights on and off with switches from different positions. I'd like to have them switched ...
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2answers
36 views

MIC1557 clock frequency constantly increases. Why?

I'm trying to get a 19.2 KHz frequency out of the MIC1557 clock generator. I managed to get close enough (enough for my application) to this frequency with off the shelf components. The shematic is ...
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3answers
105 views

How to generate clock in 7555 timer?

I am trying to simulate ICM7555 timer on proteus schematics. However, after following the datasheet for Astable operation, I don't see any results on the analog analyzer. Can anyone tell me what I am ...
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1answer
42 views

Generating the hardware delays using timers in STM32F2

I am new to this controller STM32F2xx. Here is my code, this code was given by my senior. It is working, but I don't understand how to calculate the prescaler and ARR value for 1ms delay. Can anyone ...
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1answer
38 views

Timer IC that doesn't reset count because of power down and remembers last state [closed]

I'm looking for a timer/RTC that will count how long the system power was up in total and will toggle a pin after a specific time that will be configured in advance. Does a timer that "remembers" ...
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2answers
159 views

What is the function of Zener diodes in an astable multivibrator?

I came across this schematic in my textbook which has back to back Zener diodes connected to the output of an astable multivibrator using op-amp which apparently varies the peak to peak output ...
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42 views

Why can a capacitor connected to ground in a 555 astable circuit change pin 2s output?

beginner here. Basically my question is exactly as it says in the title. I was watching a video ( https://youtu.be/qfWIjb48mjE ) about 555 timers and was wondering how the capacitor can change the ...
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2answers
141 views

Calculate time on power on delay

I am trying to make a time delay circuit (see the image) in which when press a momentary button the relay will stay open for a specific time. I tried my circuit but I cannot calculate the time (I ...
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67 views

STM32F303 timer interrupt randomly caused if started in main loop

I am experiencing a really odd behavior of the STM32s timer interrupt. I have two timers. tim3 runs at a fixed 40 Hz and calls a registered function if updated. tim2 is started after tim3 caused an ...

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