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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29 views

How to generate 1min timer interrupt in PIC24F

I m trying to generate a 1 minute interrupt using pic24F seires... To be specific PIC24Fj64GA306 Here is the code snippet ...
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1answer
56 views

555 and transistors: using a transistor to ground the reset pin of a 555 and how to drive a MOSFET with a 555

Parachute Deployment Timer I am busy trying to build a parachute deployment timer for an amateur rocket using 555 ics What have I done thus far I have a switch that closes temporarily while the ...
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1answer
68 views

What type of 555 timer circuit is this [on hold]

Could someone please describe what sort of 555 setup/circuit is in the image and how it operates. This is the webpage on which I found it http://www.thefintels.com/aer/protected/timer.htm Thank you ...
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2answers
280 views

555 timer with output voltage equal to 5V?

I am (still) learning about electronic and want to get a 555 timer. From a datasheet (page 5) it looks like when the input voltage is 5V, then the output voltage is only 3.3V. Is that correct? If ...
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1answer
81 views

Can the STM32 DMA speed be controlled by the timer?

Is it possible to have the DMA controller on an STM32 transfer each packet only when a timer update event occurs or can you only control the start of a whole chunk of DMA? The use case is (on an ...
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1answer
34 views

Generating a clock from timer using PWM

I am using CC2640 from TI in one of my designs. As per the datasheet, I can output a clock of maximum 32KHz to any external circuit/IC. As per my design, I Need to provide 1MHz clock to a sensor. ...
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0answers
54 views

STM32 Encoder mode + Input Capture on the same timer

I want to use CH1 and CH2 in encoder mode and also CH3 in input capture mode, all this using one timer (TIM3). Is it possible? I didn't found any warnings in datasheet. I looked at the block diagrams ...
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2answers
39 views

Generating pulses via timer match output or timer ISR?

I'm using LPC1778 uC for a project and want to know what is the difference between generating pulses via timer match output and via toggling a pin in a timer ISR. What are the pros and cons of both ...
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3answers
132 views

How to implement precise delay function in Keil c51 (for c8051) that waits exact amount of CPU clocks, the number of clocks ranges from 1 to 255

So as the title says, I need exact delays, not too long, ideally in the range of 0 - 350 CPU clocks, but if anything would work in narrower range the absolute minimum range is 20 - 127 CPU clocks. So ...
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1answer
48 views

Large timer interrupt instructions [closed]

Assume that it takes the micro-controller 1 microsecond to execute an instruction and the timer overflow has also been set to 1 microsecond and in the timer interrupt handler we have some instructions ...
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3answers
87 views

Uart Transmit every 1µs Interrupt StM32 NucleoF401-Re

I am using the STM32 Nucleo F401-RE and HAL libraries. I would like to send value through UART to the PC console every 1µs interruption. Actually I want every 1 µs interruption to increment a ...
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1answer
38 views

Why I am seeing a spike of 9V on output and capacitor in 555 timer

I would like to have high voltage at output initially for a period of time, then low and high ... . But in the following circuit, I see spikes on output (green) and capacitor (blue) for a short period ...
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0answers
17 views

Understanding how to use a counter and timer for a fixed number of counts

I'm going to generate pulses indefinitely with a 555 timer and use have a counter such as the below one count from 0 to 64 or another power of two and convert the output into an analog voltage to ...
-2
votes
1answer
64 views

Help choosing component values for a relay delay circuit

I want to build a circuit that controls a relay with the following specifications: the relay should turn on and stay on for ~60 seconds after the button is pushed the relay should stay on as long as ...
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3answers
84 views

Deciding Timer Interrupt time

I have used timer interrupt in my application, mainly for timing reasons like timeout detection for processes,pulse generation etc, every 1 ms. Now i have a doubt. Suppose in main(), if im doing ...
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4answers
78 views

Purpose of Resistor - comparator

I am studying this time delay circuit and am curious to know the purpose of the 4.7kΩ resistor. As I see it, it has no purpose. I've built and tested this circuit with and without it and see no ...
2
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0answers
48 views

Implementing periodic sensor data storage and GPRS transmission

I am using custom hardware driven by a TIVA TM4C (specifically, TM4C123GXL) to control a microgrid with battery energy storage, solar panels, four loads controlled by relay, and a SIM900 GSM GPRS ...
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2answers
70 views

MSP430FR4133 timer interrupt

I am trying to use the timers on the microcontroller in order to count up to 10us then add 1 to the int timer. I intend to use this in a project I am doing where I count the time between pulses from a ...
0
votes
1answer
49 views

Triggering a LED and interrupting it quickly (with a PIR sensor). What do I need for this?

I'm an artist working on a interactive installation. I'm a beginner in electronics and I'm feeling a little bit lost here, can you help me? I have a 5v circuit with a PIR sensor activating a LED and ...
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1answer
53 views

I have this timer circuit. Push and release vs push and hold give me different times

I have a timer circuit which I slightly modified from the one in this link I have an image below of what my circuit looks like. My problem is this: When I push my start button and immediately let ...
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1answer
58 views

555 autostart counting

In a monostable configuration of the 555: http://circuitdigest.com/electronic-circuits/555-timer-monostable-circuit-diagram I have connected pin2 to the ground all the time. My goal is that once the ...
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3answers
92 views

8 bit PICs: timer1 asynchronous vs synchronous operation

The 8-bit PIC family (I'm working with pic18f46k22) offers some timers (timers1/3/5) that can work in both asynchronous and synchronous modes when clocked from an external source. The obvious ...
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3answers
87 views

Servo control using dsPIC33's Output Compare and Timers

I am trying to control a single servo using output compare and a couple of timers. Timer 2 provides the 20ms period and it controls output compare 1 (OC1). OC1 is running in continuous pulse mode, ...
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1answer
24 views

Circuit that randomizes shut off time to LED's from 1 - 3 seconds when switch is thrown

I have been asked to create a circuit that drives a set of LED's that when switched off uses a random timer from ~1 - 3 seconds before the lights go off. This will be used in a light signal box for a ...
0
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1answer
56 views

555 timer digital clock

How would you go about connecting a 555 timer to a circuit with a 16x2 LCD display, which is already connected, to create a digital clock that counts the time? Do you have a sample of how this code ...
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1answer
61 views

ATmega48PA: can not run PWM on OC0A and OC2A pins

I have some troubles trying to run Fast PWM on OC0A and OC2A pins. The code is the following: ...
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1answer
51 views

Setting up a counter on STM32F405xx

How do you correctly setup Timer9 (TIM9)on an STM32F405xx to count pulses on rising edge? Is there a special configuration for the pin to the timer outside of this short example? Here's what I've ...
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1answer
39 views

555 delay circuit is unsatble

Hello I have built the 555 delay power off circuit by using these 2 guides: home.cogeco.ca/~rpaisley4/LM555.html#30 http://www.electroschematics.com/5963/adjustable-timer-1-10-minute/ I using a ...
2
votes
1answer
64 views

AVR PWM output delay before start

I'm using an ATtiny85 to generate a PWM output (using Timer0 in OCR mode), and this PWM output is being switched on and off at regular intervals. I am finding that when switching on the PWM output, ...
0
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3answers
115 views

Is it possible to call Timer ISR when we want it to execute.?

I am using PIC32 and I am doing a timer example. I am using the example of Timer1 provided in microchip documents. My understanding with the timers is when our main program start, timer also start ...
4
votes
6answers
396 views

Calculating Milliseconds using timers in PIC and synchronizing it with DS1307 timing

I have used DS1307 in my project which gives me the values of Hour, Min, Sec but I also need values of Milliseconds. I am ...
0
votes
1answer
96 views

Transistor delay switch equal to a SPDT Relay

I have a circuit I need the functionality of a SPDT switch that is flipped a couple of seconds after power is applied. It is just switching data lines on a USB port so there is no current being ...
0
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1answer
60 views

Timers and counters

I have to build a ladder diagram for a system which sounds the alarm if inside 60 seconds after pressing the start button,10 objects have passed.The alarm goes on until we press stop.In the system we ...
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1answer
100 views

Count pwm pulses on pic

I'm working on PIC18F8722 to generate PWM for 50% duty cycle. I have obtained the PWM and now I need to count the PWM pulse. As per my knowledge we can use timers to generate and count those pulses ...
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2answers
65 views

PIC16 10hz timer with timer1 and 1Mhz clock

I need to increment a stopwatch at 10hz using timer1 on a PIC16F628. The external clock is 1Mhz, supplied by a packaged oscillator (EPSON sg8002db). With no prescaler, the value to set the timer to (I ...
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votes
2answers
102 views

Count external clock pulses for a predefined time interval (PIC16f877a)

I need to count external clock pulses for a predefined time using PIC16f877a. I don't know what to use, whether counter or timer or both. I don't know to use timer and counter modules of PIC16f877a. ...
0
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2answers
124 views

Is it possible to implement a fail-proof watchdog timer in software?

I want to add a piece of code for watchdog timer within my source code so that the board resets automatically when programs hangs. I am using Mediatek Linkit One board.
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0answers
53 views

How to set MSP430 Driver Library timerA configurations

I am using MSP430F5529 and MSP430 Driver Library. As you can see, I set upMode timer configuration, compare mode configuration and enabled the initial interrupts. However, timerA interrupt is not ...
0
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3answers
145 views

Timer sequence with delayed off and long trigger pulse

Attached here below is the input and out put sequence that I am trying to achieve with a timing circuit. This looks like something that might be achieved with a few monostable 555 timers, but I am ...
0
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1answer
82 views

How to calculate the Timer Preload Properly on PIC32MX575F

I am trying to achieve 1 second on a timer in PIC32MX575F but somehow I am not reaching what I want. Some people says I have to look into the the PLLDIV, some other people says I should look into the ...
1
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2answers
147 views

Electric Timer With a Micro-Controller

I am trying to replace some electric timers with some sort of a micro-controller based solution http://www.directindustry.com/industrial-manufacturer/panel-mount-timer-154503.html. I would like to run ...
0
votes
3answers
111 views

One month timer circuit

I need to cut a signal wire after one month from it start working. So I am looking for timer circuit that it work by small battery make a short circuit for my signal wire after around ( few days more ...
0
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1answer
92 views

Timer in ATmega2560

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0
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1answer
87 views

PIC32mx Timer5 not working

I am struggling to put my Timer5 working properly. I think I have enabled all the registers but the interrupt never occurs. I already put a break point inside in the FingerprintRun() in the asm("nop") ...
0
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1answer
183 views

Bit Banging UART PIC32mx

I am trying to bit banging an UART Port using PIC32MX with timer5 (the only available at this time) but I am struggling how to configure the timer for a Baud Rate of 115200bps. I don't want a flow ...
0
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1answer
41 views

Improve a simple “magnetic alarm” with a timer, to extend the ringing time

I've bought this simple "alarm" for a door: Which is internally provided with a reed switch; inspecting the internal circuit using a multimeter, I figured out that when the magnet is placed near to ...
0
votes
0answers
58 views

Proteus and AVR watchdog timer problem in turning off

I created a small avr (ATMega32) controlled circuit that needs to be reset every 1 hour. i used the procedures by atmel that also explained here on SO. The procedure works easily on avr micro, but ...
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2answers
84 views

Complicated photo-motion-timer switch design?

Here's my scenario: I have an array of 120V LED fixtures that need to be turned on for 10 minutes when the following conditions occur: It's dark out AND Someone walks in front of a motion sensor ...
0
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1answer
154 views

Circuit for automatic watch winder

Looking for some advice, completely new to electronics so please bear with me. I am currently working on a project to build an automatic watch winder, I have a 12v 10rpm motor which should be ...
0
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2answers
63 views

Unable to set time for PIC32 timers

I am using PIC32MX795F512L. Using Peripheral library to generate timer interrupt. Following is the code I am using: ...