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Questions tagged [timers]

Timers are the hardware in the processor used to count and time events. Use this tag for questions about the hardware timers.

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0answers
27 views

Why does my TFT keep turning white after moments?

Alright, seems there is something wrong I am doing that I don't understand. Before I start explaining, my question is different than this white screen question. First of all my TFT ST7735 is working ...
3
votes
4answers
13k views

How do I count time in seconds?

I have a statement: if(control > 100 && control < 130) { //count time 30 seconds and open pin1 for 3 seconds. } How can I count 30 seconds and open a pin for 3 seconds?
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2answers
45 views

Start / end events using milis

I want to start a relay, have it run for 3 seconds, stop for 10 seconds, repeat. I can't use delay, because I have a motor driver starting / stopping every 100 milis. So I put together this code, ...
1
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0answers
624 views

ATtiny85 Comparator C interrupt on timer 1

I have a program that uses Timer1 comparator A in CTC mode. I realize that I need to set OCR1C for the timer to reset at given value. However there is no such thing as an interrupt generated by timer1 ...
9
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6answers
30k views

Very long delay() possible?

I'm trying to make an opening and closing little door that should open or close every 12 hours. I was wondering if I could just make a small looping script with a delay() for 12 hours, delay(43 200 ...
2
votes
1answer
15k views

Getting BPM from the given code

I have found code that can blink an LED on Arduino according to Heart Beat. I am using AD8232 as a sensor for Heart Rate. Code for it is: // Variables int PulseSensorPurplePin = 0; // Pulse Sensor ...
0
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2answers
37 views

esp8266 deep sleep timer slightly inaccurate?

I'm making a door open timer using a hall sensor and have a wemos d1 mini that uses a deep sleep to sleep for 1 minute after checking the hall sensor state and printing the value on the serial port. I'...
2
votes
0answers
863 views

Timer CTC Set and Clear modes — How to un-Clear and un-Set?

Nick Gammon's cheatsheet for the Ardunino UNO's ATmega328P (below) shows some hints on the Clear Timer on Compare (CTC) modes of AVR chips. Most of the examples for CTC mode I find use the COMxxx ...
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2answers
34 views

How to drive Arduino UNO as a counter triggered by 555 timer's output (astable mode)

I have an Arduino Uno and a 555 timer configured to astable mode. What I'm trying to do is to program my Arduino to increase a "counter" variable (counter++) everytime it gets triggered by 555 timer'...
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0answers
16 views

Moving timer-related code into a separate file causing timing inconsistencies?

I have written the following code, attempting to re-implement the Arduino micros function: main.c #include <avr/interrupt.h> #include <stdbool.h> #define CLOCK_CYCLES_PER_MICROSECOND (...
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1answer
118 views

set arduino own timer about 5 minutes

I want to program arduino uno by using it's own timer , which instructions and codes should be used if i want timer to be set for 5 minuets and then warn me about an event , the problem is that , the ...
1
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1answer
707 views

ATSAMD21 sleep + watchdog?

Has anyone got sleep/standby + watchdog to work together on their Arduino Zero or Sparkfun SAMD mini? I am able to get the WDT to reset the device, and am able to put it to sleep - but can't get the ...
0
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2answers
88 views

How to increase the serial port's data throughput

I have an array of numbers that will be subtracted from the ADC readings of a 50 Hz sine wave. Using Serial.begin(57600);, I can only output 25 samples per sine wave cycle, or about 1,250 samples ...
0
votes
1answer
27 views

Arduino Mega - Enabling CTC mode disables timer

I'm trying to use timer3 on an Arduino Mega 2560 in CTC mode. However, enabling CTC disables the code entirely. Here is the function I call in setup() to setup the times. void SetupInterrerupt() { ...
1
vote
2answers
282 views

Attiny85 Timer 1 comparator B doesn't work properly (while A does)

I'm writing a simple program that is using Timer 1 comparator B to generate a square wave on DEBUG_PIN. So my code at first turns on timer 1 with prescaler 8192 so that one tick is approximately 1ms....
0
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1answer
236 views

generate two phase-shifted PWM pulses triggered by frequency-divided external signal with Arduino uno?

I have a 4kHz pulse as trigger and I need two phase-shifted PWM output with divided frequency from arduino uno. Now I've managed one PWM output using the following code: int cnt = 0; void setup() { ...
0
votes
1answer
40 views

How do I start a task and have it run for a set amount of time?

I have a project where I need to turn a 24V solenoid on for a set amount of time, then have it turn off. I am rather new to Arduino and not certain how to do this or really where to start. Ideally the ...
0
votes
1answer
632 views

Arduino Zero - Stepper control (interrupt)?

I have a stepper controller board that I need to pulse every 40 uS or so. I also have I2C sensors and Serial writes to preform. Currently I run an update call in a tight loop, but the I2C sensors ...
1
vote
1answer
621 views

Timer0 overflow interrupt not working

I try to use the Timer0 of an Arduino Leonardo (ATmega32u) to trigger an interrupt at regular intervals, using plain avr-gcc (not the arduino library). I try to blink the built-in LED as test, but it ...
2
votes
3answers
405 views

Moving wiring.c functions from timer0 to timer1

I am using an Arduino Leonardo (ATmega32U4) and need to use timer0 for PWM. Since by default in the wiring.c file the functions micros() and millis() use timer0, I decided that, since timer1 isn't ...
1
vote
1answer
55 views

Measure cycle count and time of Digital Input

I am currently working on a project which is read a digital input signal from a machine. The machine operation is as below: when the mold close, the machine gives the "HIGH" signal, when mold is open ...
3
votes
1answer
72 views

Why is no PWM signal generated using Timer 2?

I managed to work with timer 0 and 1 but am unable to generate a PWM with timer 2 in my atmega328p. This is the code: #include <avr/io.h> int main(void) { /* PD6 output */ DDRD |= (1 &...
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0answers
34 views

PWM C Code some logical error

I don't know what's wrong with the code I have activated all the bits I need. I want the code to slowly increase the brightness of the bulb and then reset and then the same thing goes on. Please help ...
3
votes
1answer
89 views

Code test the duration press of the button

I wrote code that tracks the duration of a button click. It has bounce protection and frequent clicks. (Freeze) My code: bool freeze_time, btn_read, debounce; unsigned int freeze_timer, btn_timer; #...
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1answer
72 views

Enable and disable individual interrupts

I am working on timer interrupts and external interrupts. for external interrupts I understood the functions like attachInterrupt. detachinterrupt for individual interrupts ,noInterrupts() and ...
1
vote
1answer
48 views

Force TCNT to stay below OCRxA on ATmega328P

I'm using a timer and the TIMERx_COMPA ISR to generate a signal in "the background". This ISR is triggered when the timer reaches a certain value (OCRxA), which in turn can be changed by the user. ...
2
votes
0answers
49 views

What does “Update of OCR1x at” mean in the WGM table of ATMEGA328?

I just finished a reading a couple of online guides on how to use timer registers with pulse width modulation, so I'm still new to its concept. When I looked in the ATMEGA328 specification sheet, I ...
1
vote
0answers
71 views

Millis() is Not Working

I have a sketch that uses two timers using millis() from a library I created to keep time. The timers seem to be working correctly, but when I print the start time of each timer, it is clearly wrong. ...
0
votes
1answer
69 views

timer library on Arduino DUE

I'm trying to call an interrupt routine (let's call it handler() ) every second on my arduino DUE. I thought the simplest way to do this was to use this library but it seems that i don't know how to ...
2
votes
2answers
207 views

Button for Delay Select

My target is to make an Arduino system that is able to change modes with different delays by pushing a button. For example, if I pressed the button, it will go into mode 1 with loop 1 that has a 30s ...
-1
votes
1answer
182 views

Handling overflow in micros() [duplicate]

The documentation for micros() says: Returns the number of microseconds since the Arduino board began running the current program. This number will overflow (go back to zero), after approximately ...
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0answers
23 views

TimerOne and Saving Data to SD Card

I'm using TimerOne.h for collecting sensor (two photocells) data with a frequency of 100 ms and saving the data to a SD card. The file only seems to save data when the computer is connected to the ...
0
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0answers
230 views

timer interrupts on an esp8266

Folks. I'm working on an ESP8266 and keen to switch to using: an object approach -> sorted; physical interrupts on the hardware pins -> sorted; timer interrupts -> driving me crazy! My problems are ...
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votes
2answers
39 views

Can I use a pot to vary duration of timer circuit without writing code for each time interval? [closed]

I would like to be able to use an Arduino as a timer control to switch on/off a 120VAC load. I think I can do that with the Arduino triggering a small relay controlling the 120V contacts. But I need ...
0
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0answers
122 views

ESP32 changing PWM duty in ISR

I'm implementing code for a multiplexed 7-segment display (4 letters), e.g. it has two common cathodes and each pin corresponds to two segments depending on which cathode is grounded. I have written ...
0
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0answers
46 views

How to generate 4 square signals using Arduino Mega 2560 below 30hz using timers

I would like to generate 4 square signals of different frequencies below 30 hz using timers of Arduino Mega. I was able to generate 30.6hz signals but I have no idea how to generate lower frequencies....
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2answers
51 views

Please Correct my Delay Code without using delay();

This is my loop()function: if(Serial.read() == 't') { tarestate = true; } while(tarestate == true) { timeNowTare = mills(); if(mills() - timeNowTare >= 3000) { Serial.println("Tare"); ...
1
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4answers
2k views

Generating a 38 KHz signal without timers

I am currently trying to generate a 38 KHz signal for my TSOP4838 (http://www.vishay.com/docs/82459/tsop48.pdf) with an ATtiny84A. I know the real thing would be to utilize a timer but the ATtiny ...
0
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1answer
97 views

Does enabling the Timer1 CompareA interrupt instantly triggers an interrupt?

I am learning Arduino interruptions and I am unable to explain the behavior of a minimalistic interrupt driven project. The project is the following: an Arduino UNO is connected to two LEDs, on ports ...
0
votes
1answer
159 views

How to find the difference between two timestamps

I'm using this time library to access the properties of unix timestamps like hours / minutes / etc. What I want to do is get the current time, and an estimated arrival time, and find the difference ...
0
votes
2answers
255 views

Inaccurate PWM Signal Frequency and Timing

I have a Teensy 3.2 and I am using the Arduino IDE to program it. I am trying to generate 8 pulses with the frequency of 40 kHz and this needs to be repeated every second. I have written 3 different ...
2
votes
1answer
148 views

Triggering a soft reset (Arduino Leonardo)

I want to trigger a soft reset on my Arduino Leonardo, and after some searching settled on using the watchdog timer, as it seemed to be the easiest and cleanest way to do it. However, I don't think ...
2
votes
1answer
162 views

Trying to run Timer1 in ATmega2560 with assembly

I have a slight problem with Timer1 in arduino (ATmega2560) while coding it in assembly. I try to run the Timer1 in CTC mode - I configure everything well in my opinion, but the TCNT1 just doesn't ...
2
votes
2answers
366 views

How to read a timer's value once stopped?

I've downloaded the Timer1 library but unfortunately it seems that the read() method has been removed from it. I tried also SimpleTimer library from the arduino website but the program didn't compile ...
2
votes
1answer
6k views

Arduino continuously reading ADC value using interrupt

I have a mono jack audio act as analog input for arduino UNO. The microphone outputs voltage that varies in terms of amplitude (volume) and frequency. In order to get the high sampling rate, I use ...
0
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1answer
45 views

How to set time for 15 seconds

When user used one password after close the servo the password will valid for 15 seconds then it will not work. Other 9 will be same process Here is code I need just this to set int locker = 13; ...
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1answer
78 views

Can I use arduino to generate 8mhz frequency ultrasonic pulses in piezo discs?

void setup() { pinMode(freqOutputPin, OUTPUT); Serial.begin(9600); // Set Timer 2 CTC mode with no prescaling. OC2A toggles on compare match // // WGM22:0 = 010: CTC Mode, toggle ...
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1answer
68 views

Using timer classes within classes

I am trying to develop a class for a pump that works on a stepper motor, it should be simple but its not working the way I thought it would. Once I move the timer object into the class the code wont ...
8
votes
4answers
1k views

Turn Arduino on with timer every 24h

I'm currently working on an Arduino project that sends the charge of my car battery once a day via an ESP8266 to me. During the winter I don't drive my car, and I would like to get informed when the ...
0
votes
1answer
61 views

What is the smallest duration that can be measured using micros()? [closed]

What is the least value of time that I could measure(count) using micros()?