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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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25 views

Measure pulse width with STM32L0

I want to get data from a HC-SR04 sensor with a STM32L0 board. The way to obtain the data is the following: I need to measure the echo pulse width but I do not know where to start. Do HAL libraries ...
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3answers
67 views

Need help understanding RC discharging through a transistor in a timer

Once I push and release a pushbutton I want a LED to light for say 10 seconds. I found a design for this on the web and tried it out: What I observed on the breadboard was that the LED lighted for at ...
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1answer
30 views

Dusk dawn motor driver with polarity reversal

I'm trying to accomplish this. When a dusk dawn switch is on, drive a small DC motor for a few seconds and then stop. when the dusk dawn switch is turned back off, then turn a small DC motor THE ...
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2answers
143 views

Is the circuit in this answer wrong?

In the Q/A link below, the circuit in the answer seems to be wrong to me. Answer to "How to gradually light up an LED?" Circuit: simulate this circuit – Schematic created using CircuitLab In ...
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48 views

Power-On Reset (Once) with a 555 timer

I have a dehumidifier that works with a push button. Unfortunately, where I live we have continuous power cuts. This puts my dehumidifier off, which means if I'm not home the unit is off all day. I ...
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38 views

AVR timer: CTC mode

I am having some trouble understanding Timers in AVR, especially CTC mode In CTC mode when a match occurs I can toggle OC1A or OC1B pins. As per the data sheet In clear timer on compare or CTC ...
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50 views

Low power analog timer circuit

How can I achieve the following: When a switch closes momentarily Hold a mosfet switch closed for about 15s. Then gradually reduce power to zero over about 4s Using little-to-no power when not ...
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1answer
64 views

Six monthly service timer with indicator

I have been requested to look at a project. The first half of the project is complete, but I am struggling with the second half of the requested specification. For the second half of the project, I ...
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1answer
37 views

Why is the potentiometer setup in this configuration in this 555 circuit

I just started learning about chips and signals using the book Make: Electronics, in one of the circuits, used to generate a pulse in Monostable mode a potentiometer is used to vary the pulse length....
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38 views

Timer activated by Reed on AC solenoid

Let me start by saying thank you for taking the time to read this - I really appreciate it! To the point: I am trying to create a 2-digit timer that resets and then starts at the activation of an ...
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49 views

Providing an input event to timer to enter into ISR on Tiva Launchpad TM4C123GH6PM on Code Composer Studio

I am writing a program in CCS to count the time every positive edge from 32-bit wide timer, where the time is updated in the widetimer5's ISR on Code Composer Studio. I read the datasheet, but I am ...
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1answer
15 views

Timer Interrupt Setup in ThreadX

We're trying to set up ThreadX for the first time and we're trying to understand all the timer settings that. Although there are basically two constants that we need to set, they are not really clear ...
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19 views

Can standard 8051 timer 1 and timer 0 be available to programmer when serial mode 1 is used?

The micro is an AT89C4051. It allows two timers and a serial port interrupt. Currently, I set things up so that if any kind of data is received on the serial port, it just is loaded into memory by ...
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1answer
103 views

STM32L0 - Delay in microseconds

I am using a B-L072Z-LRWAN1 board (which has a STM32L072 MCU) and I want to get data from a DHT11 sensor. To achieve this, I need a microseconds delay which I am not able to obtain. The libraries ...
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1answer
39 views

How to turn off 555 Timer for a period of time after Vout signal passes through

I have a single-shot 555 Timer. After triggering, output goes high for a period of time. What I would like to do now: After Vout goes high and then low again, I want to disable the 555 timer for a ...
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1answer
38 views

STM32F030(K6) Systick not triggering (BOOT0 problem)

I'm trying to write a simple program for a STM32F030K6T6 microcontroller. The problem I am facing is the more common "Systick is not working" problem. The code is generated using Cube32MX (Firmware 1....
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1answer
52 views

COMP2 to trigger One-Pulse mode on STM32L1

I am trying to use the output of COMP2 to trigger the One-Pulse mode of a timer (in my example TIM4, but it's quite flexible if it needs to change to another timer) on the STM32L1 series. In the ...
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3answers
1k views

Difference between internal and external oscillator for a microcontroller?

I am a beginner with respect to microcontrollers, so I just want to ask is there two option for choosing the frequency of the microcontroller: to be internal or external? If there is internal ...
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23 views

Heater cooler control

I would like some sign posting to how I can produce a system. The components I have are so far, Fan control PWM based I think as I tried a variable voltage and the fan just didn't last more than 2 ...
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63 views

STM32: RPM calculation with existing timer

I'm beginner and I wrote this code few months ago. It's working quite well. Purpose: I read an encoder value in order to drive a stepper motor (and display some info on a small LCD screen). I just ...
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1answer
44 views

Open and Close Circuit automatically (Automate Push Button)

I have a simple circuit board with a push button on it. I just want to automate the pressing action every 0.2 sec or so. The push button has two terminals underneath and I understand that I should ...
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75 views

strange array values (C, psoc, usbuart)

I am still fairly new to programming, so I'm sorry in advance if my terminology/formatting isn't up to scratch. I am currently working on an element of a musical instrument that will allow me to ...
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2answers
50 views

how do I implement a start timer in a digital circuit

In vhdl, I know how to code a start timer behavorially. However, if I have to implement such a counter to start based on a trigger, how could I implement such a counter? My trigger is another signal ...
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1answer
65 views

555 Timer circuit analysis

I am trying to analyse a 555 based timer circuit: My current understanding of the circuit is that the output is changed by the voltage at pins 2/6 (let's call it V). If V drops below 1/3 Vcc, output ...
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49 views

STM32f103 multiple TIMER IRQ to generate different timebase using SPL

I am trying to control two LEDs with different delays.I used CUBEMX for code generation and used TIM2 and TIM3 to generate different timebase. It worked without any issue. Simply using TIM2_IRQHandler(...
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45 views

Help! NE556 PWM circuit for controlling MC-2100 DC motor driver

I built a 556-powered PWM controller as explained in pg 10 and 11 of this PDF document: https://www.dropbox.com/s/3ous60tvartqibb/Terry%27s%20Dual%20555%20MC-2100%20Driver%20Circuit.pdf?m The ...
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1answer
85 views

Generating 1 second with avr and timer 0 for Atmega32A

dears: we have to Generate 1 second with atmega32A and mikrobasic software. so I have configured timer 0 and avr with this way: ...
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1answer
57 views

How is a long timer implemented?

Given the following constraints: ~20% accuracy or better Vcc=5V Input is the falling edge of a TTL signal Output can be TTL or the input to a Schmitt trigger Time between 1-60min adjustable via pot ...
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74 views

STM8 - Unable to use timer2 with interrupt

I am trying to run timer interrupt in STM8 microcontroller. But I am not able to do so. I tried to read the counter Register and ARRP, but after loading the value as well both registers had the ...
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1answer
76 views

Expected behavior of 555 timer in monostable mode

While assembling the 555 timer based circuit below I noticed that 1) the intended delay on pin 3 only works if the switch on pin 2 is closed before attaching the circuit to the 9V power supply. ...
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2answers
122 views

Using Timer 555 to obtain a frequency multiplier

How can I use a timer 555 IC to obtain a frequency multiplier? I made a frequency divider by using a timer in monostable mode but a multiplier looked difficult. Can somebody tell how can I design a ...
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1answer
43 views

What's the name of a timeout relay which won't re-trigger if it times out?

I would like to replace the relay which triggers a water pump, with a relay which times out after, say, 10 minutes. And if it times out, it stays locked out until reset. Needs to be 230v AC on both ...
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97 views

STM32F407 - how do I run one motor at a time? Why do they ignore delays..?

I'm a newbie. I'm using an STM32F407 discovery board, and I want to control 6 stepper motors using PWM, especially OPM(One Pulse Mode). Till now I've made 3 stepper motors work using Timer 8 (CH1, ...
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1answer
182 views

STM32 Logic level high and low thresholds

I am scratching my head to find what are the minimum voltage for registering a low digital signal and maximum voltage for registering a high digital signal when I configure GPIO pins of STM32 (I am ...
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1answer
91 views

How to avoid this voltage when I turn on the circuit?

What I want to do is an Delay ON, but when I press the switch this voltage pass for a brief moment and turns the led on for a moment. How can I avoid this? Should I put the switch somewhere else? ...
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1answer
107 views

Why can't I route the same signal to multiple pins on an STM32F407?

I have a periodic signal which I want to use as a trigger to two timers - TIM8 and TIM2. When the signal goes high, TIM8 should start running and TIM2 will be clocked once. TIM2 will be configured in ...
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2answers
56 views

Hold Pushbutton for soft latch after X seconds

What I'm trying to achieve is have a momentary push button that must be held for say 5 seconds before latching on permanently. But the button must be held for entire duration or else timer will reset....
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44 views

Suggestions for switching 800VDC converter on/off

I'm stress testing(turning them on-off with load every 300 seconds for 1-2 weeks) the components that we are willing to use. have tested several battery chargers with AC input with using a timer relay ...
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19 views

HM-TRP radio module works at 56K data speed but only in delayed chunks

I created the following setup: I created one circuit in which the PC connects to an HM-TRP radio module via a max232 DIP IC. This circuit for the test is the master to all devices and sends a 16 byte ...
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1answer
62 views

Led as an input photodiode [Arduino AVR]

I’m trying to use a LED as a light sensor(input) connected to a Arduino Nano. I connected the led with the Anode at digital pin 8 (PB0) with a resistance of 56 Ohm and the Cathode at an analog pin A0 (...
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2answers
202 views

TPL5110 doesn't work with NodeMCU

I am using a TPL5110 timer to drive my NodeMCU, in order to keep battery consumption low, but I can't let it work. I have setup the standard circuit for this timer, as below: Whenever I apply power ...
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1answer
322 views

TIM2 DMA configuration for stm32h7

My problem: I can't configure DMA to working properly on Input Capture event. Data doesn't transfered and error occurs. ...
2
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1answer
131 views

Error setting up timer HAL PeriodElapsed Callback STM32F334R8T

I'm trying to create a microsecond delay function using the STMs regular timer. I wanted to set a timer to fire an interrupt every microsecond and then increment a variable in the call back function ...
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1answer
697 views

STM32F4: How to get data from multiple channels sampled from a single ADC?

So I have searched everywhere for a solution to this problem but I can find anything. I have three channels connected to ADC1 of my STM32F446ZE-nucleo and I want to ...
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2answers
142 views

Changing frequency of 555 timer with varicap or capacitor

I have created a 555 oscillator circuit where the output is set to have flashing LED light. Now I have a problem when I change the voltage of the potentiometer, the output frequency does not change. ...
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3answers
86 views

Delayed, active low, short pulse for reset

I am attempting to create a circuit using a TUSB2036 usb hub IC that automatically starts when it is powered on. The datasheet states for the inverted RESET pin RESET is an active low TTL input ...
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37 views

What keeps a delay-off timer energized when you cut off the power?

I've come to understand the function of the delay off timer as follows: When it is energized, it instantly changes its contacts. And when you "de-energize" it, it delays for a preset time and only ...
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51 views

Led on for one minute eve if the switch is pressed for more than one minute? [duplicate]

how to make a circuit that when press the switch the led is gonna stay on for one minute and than off even if the switch is still pressed for more than one minute
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2answers
298 views

Timer1 on stm32f4

Im giving a try to stm32 after a long time programming on avr, and seems like im struggling with timer. I want to use timer for handling freezes: ...
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3answers
105 views

Can I use a mosfet as a switch to power arduino?

I have a project in which I intend to use a NE555 timer to turn the arduino on/off on specific intervals. I don't want to use the ne555 output directly because of the current limitations of the chip. ...