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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17 views

Variable Timer Circuit w/ Digital Display for Counting Down

I would like to make a timer. The timer will have a digital display and will work with a microcontroller of some sort. I would like to be able to put in a time (e.g. anywhere between 0 - 10 minutes) ...
1
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1answer
39 views

What the output isn't correct when I use a switching power supply?

I have a circuit that it is a STM32F103RET6(Reference Manual) board and one LCD. everything work very well just one thing! PWM! when I use my J-Link debugger to supply the circuit(or USB connector), ...
0
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1answer
11 views

AVR Timer1 OCR1A controls TIMER1_COMPB_vect interrupt!

I was struggling with timer interrupts in my project. I couldn't make it work properly. So I decided writing a simple code and I saw a very interesting case. ...
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1answer
14 views

AVR ATmega644p: can't clear OC0A pin on CTC mode

I made an IR blaster for controlling TV (on and off) based on ATmega644p. I am using Timer0 in CTC mode to generate 38kHz waveform. This is the code: ...
2
votes
1answer
23 views

Understanding PIC32 watchdog timer operation

I'm new to uC development and have been fooling around with the PIC series for about 6 months now. I recently started working with the PIC32 and Microchip's XC32 C++ compiler. I don't know if I have a ...
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1answer
39 views

toggling a pin using the hardware compare feature of timer1 AVR

This link - says: "In CTC mode, you can also trigger interrupts, but it is also possible to not use interrupts and still toggle an output pin. Using it this way, the functionality occurs ...
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1answer
68 views

Extremely small electric shock device - could this work?

My question is this: Is it possible to build a device which could deliver a small electric shock every hour or so, and to fit this into a standard size ring? I am talking about a small electric shock ...
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3answers
64 views

sequential leds using op amp

I am trying to design a circuit that has a timing sequence. The timing sequence will be started by a SPST momentary switch. For the first 2-4 seconds a green led will display. When the first timer has ...
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3answers
189 views

How to calculate the time of one single tick on microcontroller

I have been in Embedded system for 8 months. I have worked application part more compare with low level. I have basic questions on systems ticks, How to calculate the system tick of Timer, if I am ...
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1answer
52 views

TIMER0 in PIC18F4550

I am using PIC18F4550 I am trying to generate an interrupt every 1 sec, and by trial and error(i.e. just writing and simulating on hardware ) I am getting interrupt approx to 1 sec. Code for this ...
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2answers
61 views

Timer for turning LED's on for 4 seconds and then off for about 200 seconds

I want to build a very small, low power timer that will allow several LED's on for 4 seconds and then off for about 200 seconds, then repeat. 4.5VDC. No programming. Help please - thanks.
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1answer
24 views

Using TIMER 1 without enabling interrupt in C on dsPIC33E

I am trying to decipher a C code in which Timer1 is being used for measuring the period of a digital signal, using dsPIC33EP256MC506. The timer interrupt is not ...
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1answer
37 views

Stop timer set new value and start again AVR (Interrupt)

I have AVR MCU. I am playing with timer now. What I need ? I have timer counting up with some frequency. In each interrupt I am incrementing variable, and somewhere I need to check value of this ...
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votes
2answers
89 views

How to make a stopwatch timer [closed]

I want to make a simple stopwatch timer using simple materials such as a breadboard, a couple of IC's (integrated circuits), wires, resistors, capacitors and transistors. Is it possible without doing ...
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0answers
21 views

how to wire a timer without negative using ground [migrated]

I have a switch i would like to replace with a timer like this http://www.amazon.com/forum/-/Tx3DCN3HLSARWFS/ref=ask_dp_dpmw_al_hza?asin=B004SOZHXY i only have a positive wire in my switch box, ...
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0answers
27 views

STM32F205VC - What causes this short impulse in one-pulse mode of TIM1?

Hi! Why am I seeing this short impulse? This is my code: ...
-3
votes
1answer
64 views

AVR 60Hz periodic interrupt [closed]

How can I configure an AVR microcontroller timer to generate periodic interrupt events at 60 Hz rate, using 14.745 MHz system clock?
2
votes
1answer
122 views

STM32: Timer interrupt works immediately

This is code for timer in my project on STM32F429: ...
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3answers
69 views

Delay function using timer/counter 1

i have made a function called _MY_Delay() which use 16bit timer/counter1 in ATMEGA16 , and used this function to blink a LED . the problem is i didn't work and i don't know the reason , here is my ...
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1answer
41 views

Time delay relay

I am having trouble figuring out what kind of time delayed relay I need for this circuit or if anything will work even. It is used to keep a dome light on for a few seconds in a vehicle after the ...
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0answers
38 views

PIC12F simulator: Why isn't the oscillator running?

I have written firmware for a PIC12LF1572 that I am testing in the MPLAB X simulator. The program runs and correctly responds to stimuli, except when it needs to wait for a timer interrupt. After a ...
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1answer
66 views

How do I build a DC time out circuit that stays off until power is toggled?

My girlfriend bought an LED faucet that is actuated when you turn the water on and is powered by a battery pack of 4 AA batteries (2 wire out). However, when the water is turned off, the slope of ...
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0answers
113 views

Using Pic18F timer for external pulse count assembly code

I am new to using a Pic18f2550 micro-controller. I have been searching for examples on how to setup and use the 16 bit timer Tmr1 and Tmr2 to count the number of pulses from an external motor opto. ...
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1answer
38 views

STM32F051R8: PWM timers don't work?

I'm working with MB1034B discovery board and STM32F051R8 microprocessor. I'm trying to output some PWM pulses using hardware timers. I use this tutorial (for STM32F4xx): ...
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1answer
33 views

Measuring time using an STM32F407VGT6 microcontroller

I'm using a custom board for charging and testing batteries. Its 'brain' is an STM32F407VGT6 microcontroller. I'm developing in Ubuntu (14.04.2 LTS), using ChibiStudio (ChibiOS/RT 3.0 development ...
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0answers
18 views

program stops in non maskable interrupt when initializing time interrupt

I am using RX62N microcontroller and am new to it. In this i was trying to blink the led using interrupt(compare match timer) but after the initialization it always goes to the non maskable interrupt ...
1
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1answer
54 views

PIC18f4550 Timer setup for 1sec Interrupt

I want to generate Interrupt(on PIC18f4550 using TIMER0) every 1 sec but by using the following code interrupt is generated after every 6 secs. ...
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2answers
81 views

Turn a METAL HALIDE BULB On/Off in 1 minute Intervals?

OK, let me 1st give you some background information. I need to generate 40,000 lux of light in an indoor environment (in a area of around 5 feet by 3 feet) and I need the ability to turn the light ...
3
votes
3answers
80 views

Help Trobleshooting my first solderless circuit on a breadboard

I'm working on my first project from the book "Electronics All in One for dummies", chapter 6, book 1. I work through all the instruction but I cannot make the LED blinks. The circuit diagram is: ...
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3answers
125 views

How to turn a switch on/off repeatedly in 1 minute intervals?

I have a light bulb plugged into an outlet and I need to be able to turn it on and off again and again in 1 minute intervals for a period of 10 hours per day (a total of around 600 on/off events per ...
2
votes
2answers
54 views

On STM32F4xx: Can I trigger a timer by itself so it goes through a list of periods updated from an array?

I need things to happen at precise (down to the clock, ~5.5ns at 180MHz) periods of time based on a list; let's say 5 periods of 444444, 555555, 666666, 777777 and 888888 timer clocks (obviously a ...
1
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0answers
35 views

program resets after ISR for TIMER 2 on pic24F

I am trying to configure the timer2, but every time that an interrupt occurs, the microcontroller goes to the ISR and then starts the main() function again. This are the functions: ...
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1answer
73 views

PIC18F25K80 4 > 20 returns true. How is this possible?

I'm using such code on PIC18F25K80 compiled with xc8 compiler: ...
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votes
1answer
121 views

flow meter that displays litres per hour [closed]

for the past 2 week iv just started my first ever project to make a c program on the software called mikroc where i would get pulses in from the flow meter and calculate the flow rate of how much ...
4
votes
1answer
116 views

AVR: Timer overflow flag in TIFR [duplicate]

I have a little question about the TOVn flag located in the TIFRn register. The datasheet says, if the ...
0
votes
1answer
39 views

Frequency of the CTC mode in the atmega328

I am trying to understand the expression for the waveform frequency of the CTC mode (p. 99 of the datasheet). Assuming that the prescaler is 1 and that \$OCR0A\$ is a constant value, in ...
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0answers
37 views

Low power, low duty cycle, full speed dc motor timer

I need to drive a 12v dc motor drawing 300ma under load. It only needs to run about 4-5 seconds per min. But the run and idle times need to be adjustable with some degree of accuracy. Once ...
0
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3answers
211 views

Reversing polarity of motor with timer

I have a timer that allows me to preset times and run a motor for a predetermined amount of seconds. I need this to reverse polarity as soon as this predetermined time has expired. The timer is a ...
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votes
2answers
93 views

Using TMR0 to time an event

i'm trying to use TMR0 on a PIC18F2420 to time the opening of a device and display the percentage it is opened. the issue i'm having is that it has frozen up pretty much all other operations. i'm not ...
6
votes
2answers
161 views

Turn a mains light on slowly

I've been looking at creating a simple circuit to slowly turn a halogen daylight bulb on over about 30 minutes as soon as power is supplied to simulate dawn. I've got a 240VAC 42W halogen bulb that ...
0
votes
3answers
128 views

wiring 555 to disconnect itself from electricity

i had idea for a circuit with 555 and here is the IDEA: circuit is stationary somewhere, it is in "passive state" meaning its drawing no current from battery and pin 3 is set low, then someone comes ...
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0answers
38 views

Fan needs full power to spin up; would then like to have to run off a speed control

Fan in question: http://www.amazon.com/Active-Air-inch-In-Line-Fan/dp/B002JQ4N92 Fan speed control: http://www.amazon.com/Lutron-DVWFSQ-FH-WH-Single-Pole-3-Way-Control/dp/B000MAVHTG The lowest ...
2
votes
2answers
100 views

Design of a Five Second Kill Switch

I think I have a challenge for you smart souls on here, who donate your time by answering all of my terrible questions. I have to design a switch that completely shuts off a system when it is ...
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1answer
38 views

Timed Selection Between AC Power Sources

I would like to be able to run a freezer from AC power line A in the daytime and AC power line B at night. Right now, I am manually unplugging the freezer from power line A and plugging it into power ...
1
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1answer
66 views

Switch to power pump with relay [closed]

I couldn't find this question anywhere else. I have a pump, a 12v battery and a switch and can purchase any relays etc that may be required. I want it so that when a switch is triggered and kept on ...
1
vote
3answers
371 views

555 timer one-shot 30 second light LED strip, TOTALLY CONFUSED!

I'm working on a personal project and I am at my absolute whits end here. I have a configurable N.O. or N.C. switch (nteinc Magnetic Alarm Reed Switch) so I'm not too concerned with which way I use ...
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2answers
151 views

Circuit Requirements for a 30 min continuous on off cycle

I would like to build a circuit (preferably using components from old common electronics like a VCR or whatever) that continuously cycles on/off in ~ 30 min intervals. Input voltage is from a 12v ...
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0answers
54 views

RC compare in capture mode - Timers SAM3X

So I am using an Atmel SAM3X8E micro together with a temperature sensor over a one-wire interface. The short version is: I give the chip a sequence of setup and start pulses, and the chip responds. ...
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1answer
72 views

Where do I connect earth wire?

I'm trying to use this delay timer to control an exhaust fan. I have a 3 pin connection (with earthing wire) powering this fan and it works fine. If I have to insert this delay timer module in ...
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0answers
36 views

NTP offset error

we are having problems getting our time synchronized in an embedded processor system using a NTP server and a FPGA based hardware RTC. Our offset calculation says that the time error is 0, but our ...