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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51 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
24 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 ...
1
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0answers
36 views

STM32F4xx WFI unable to sleep due to SysTick Interrupt

I am trying to add some power conservation to our STM32F4xx powered device using its WFI sleep function. However, whenever I call the WFI function, the system is not being put to sleep (or rather, it ...
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2answers
68 views

Can you set up a monostable 555 timer so it reverses the output?

I would like to make an alarm that goes off about 1 minute after it has been triggered. To do this, I want to delay the circuit using a 555 timer in monostable, but I can't do this as they turn it on ...
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2answers
97 views

PIC16F877A Timer0 delay problem?

To get min 5ms square wave. I chosen prescalar as 1:32 (The internal clock given 4Mhz), what will be the TMR0 register value? Is it 0x64 or 0x63 !!
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0answers
39 views

Circuit that takes input signal and controls led

I am trying to design a circuit that compares a recorded signal to a stock signal. If they are not similar it then inputs a signal into a circuit which will change the pulse of the led to stimulate a ...
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1answer
41 views

Timing Delay Error

I am new to embedded system programming. I am working on clock using 8051 timer and interrupt.The delay is perfectly of 1s but when I run my clock with computer clock I loses 3-5s in 10min.I have try ...
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2answers
64 views

555 Timer Monostable Mode Self Triggering

I'm working on a simple project with 555 timer. I'm trying to generate a high-state output for 10s when Vcc is applied to the circuit(It is initially off). However, I have not managed to operate the ...
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2answers
55 views

STM8L Timer 1 unexpectedly low overflow frequency

I'm running the MCU off the high speed (16MHz, confirmed) internal oscillator and I've configured timer 1 to overflow with maximum overflow frequency: ...
0
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1answer
71 views

using one 555 timer to control the pulse of another

tried making something like this Limit Number Of Pulses From 555 Or Similar but it doesn't work. I'm not sure what it needs. I'm trying to make the first timer put out voltage to the second one for ...
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0answers
45 views

555 timing formula when the diode forward voltage drop is not neglected

(Image Sources) In this modified astable multivibrator circuit the forward voltage drop of the diode D1 is always ignored, and the timing formulas are given as $$ t_1 = \ln(2)R_1C_1, \quad t_2 = ...
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0answers
49 views

Light-dependent timer circuit design

I am a relative newbie in electronics and would like to build a circuit that controls a light or small array of lights (2 - 5W LEDs). The system will be powered by a car battery (12V) with a solar ...
0
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1answer
77 views

AVR TIMER0 treating with prescaler and without to blink a led

I am playing with ATMEGA168A's TIMER0. CPU is running at 20MHz and there are two treatments. a) Blink a LED at 20ms frequency by using a 1024 prescaler. In that case i count the the times that an ...
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1answer
43 views

3 second fogger

hello I'm new here and I have a question. I'm no electronics expert but what I'm trying to do I thought would be rather simple but I'm having trouble with one part hopefully somebody can help me. I'm ...
2
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0answers
113 views

STM32 - Multiple channel PWM input

I am using an STM32F405 based board , (OpenPilot revo ) to receive PWM signals from a joystick receiver . i have to xapture 5 PWM signals using only two timers , the timer 8 and the timer 12 . I've ...
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3answers
68 views

Designing a simple pulse generator

I read in many tutorials that the inner clock in a micro controller are less accurate (%10) than the external crystal clock. When I generate variable frequency pulses by using a micro controller does ...
2
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3answers
101 views

How are timers adjusted in a micro-controller?

In a 555 Timer the resistors and capacitors determine the frequency and the duration of the timer pulses. How is this actualized in case of a micro-controller timer?
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0answers
64 views

Power micro LED's from 5 Volt USB

simulate this circuit – Schematic created using CircuitLab I'm working with this set of LED's: Link here: 30 Ft Led wire I measured the draw for the entire string at about 170 ...
8
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4answers
1k views

555 timer: how to set values to take an hour

I'm new (and novice) in electronics. I came to seek your knowledge to see if someone can help me with a very basic circuit. It is a 555 chip, which should light a LED (for about 1/2 second) every ...
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0answers
38 views

Not entering ISR for timer 4 in stm32f4

I have coded for Timer 4 in a STM32f407vg discovery board. But while debugging the control is not entering the ISR. Please find the code below and help: ...
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1answer
195 views

STM32F4 Timer accuracy

I'm working with an STM32F4 Discovery board and I've come across a bit of unusual behavior that I'm hoping someone can explain the cause of to me. My goal is to configure a timer to trigger an ...
2
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0answers
83 views

STM32F103: not working USB when I turn on the timer

In my project the USB works, if do not use the timer 2. As soon as I enable the timer, the USB is not defined on the computer with an error -71. I use libopencm3; debian; gcc arm; what is the ...
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2answers
230 views

555 as a Schmitt Trigger and an ON delay timer?

I've scoured the internet trying to find this out to no avail. I would like to use a 555 timer to produce a Schmitt trigger with an ON delay of 20-30 seconds. Is this possible? Or will I have to use ...
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0answers
76 views

MSP430 PWM Dead-Time

According to the internet, the MSP430 has no hardware implemented to maintain proper PWM dead-time as the PWM duty cycle is modified. Apparently (and also according to the internet) this feature can ...
2
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2answers
201 views

Is there difference between Timer vs Counter in ATmega328P?

Is there difference between Timer vs Counter in ATmega328P? Or is it the same thing?
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1answer
60 views

Clock / timer activated 2 second voltage timer for wiper motor project

Ok, I need a 12 volt voltage timer using clock or timer for a wiper motor. I am working on a project in my garage. Simply put, I am wanting to use a wiper motor that will open and close a spring held ...
2
votes
3answers
89 views

Crystal or Crystal Oscillator for time sensitive device

A device that I'm working on is controlled by ATmega328P microcontroller. This will be some sort of a watch, therefore I want it to be as precise as possible. For instance if left to run for a whole ...
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2answers
102 views

555 timer to work once per day for 30 minutes

I was wondering if I could use a 555 timer to turn on a PI once per day for about 30 minutes. I want to use the 555 because it will take power from a photovoltaic source.
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3answers
369 views

How to make 7-segment display count up ?

I've connect 7447 decoder and 74193 counter as shown in the picture but I have not used 555 timer yet. Is there any way to test the circuit before using 555 ? I've connected the pins (up and down) ...
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1answer
190 views

STM32F1 troubles with a timer

I'm having some troubles with setting up a 1 second timer on STM32F103 mcu. I have set Timer 2 to have a prescaler of 1099 and a period of 65514, so I'm expecting to have a 1 second interrupt rate: ...
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2answers
131 views

Calculating how many times TIMER1 will overflow

I'm trying to understand how to set up an overflow interrupt on ATmega328 TIMER1 to measure a frequency. I'm feeding pin PD4, which is where TIMER1 is externally clocked, with a 503kHz square wave ...
1
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1answer
99 views

Input interrupt pin associated with TIMER1 on ATmega168

A few days ago I came across the source-code for this ATmega168 based Inductance Meter from Dan's Workshop Blog. Below is the code that I believe sets up an ATmega168 interrupt to measure an external ...
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0answers
67 views

Very high speed counter (2GHZ) [duplicate]

I'm trying to build a high speed counter to measure the time delay between two radio waves . I'm thinking of using a MC100EP016A counter which works at a maximum frequency of 1.4 GHz but I cannot find ...
3
votes
1answer
115 views

AVR - ATmega16 - Timer config

Trying to figure out the timer setup in Atmel Studio 6 for an ATmega16 microcontroller. And I just don't get it. I am trying to create a TickCount similar to GetTickCount() Retrieves the number of ...
1
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1answer
48 views

What's the benefit of Upcounting or Downcounting or Center-aligned mode of timer/counter?

I have done several project (3-4 project) via Timers/Counters but I'm curious to know Why do they have three mode for counting? Also I know that in Upcounting mode it count from zero to 0xff... or ...
0
votes
1answer
744 views

How to build a blinking 12V indicator LED light

I attempt to build a blinking circuit using 12V truck light ( like this one: http://www.princessauto.com/pal/en/Tail-Lights/4-in-LED-Stop-Turn-Tail-Light/8126047.p). I have try to build a single LED ...
1
vote
2answers
182 views

Executing code at diferent speeds, using one timer, and no extra RAM

I was wondering, will this actualy work? (when timer / prescaler set) It saves RAM by not using extra variables. Are the better ways of doing this? ...
2
votes
1answer
95 views

DC current stopper [closed]

I don't really know what I am looking to make is called so I am going to try to explain it. I set up a motion activated light in my room. The lowest time interval is 60 seconds and I am okay with ...
-1
votes
1answer
110 views

Improper functioning of Timer1 in pic18

I'm using pic18f controller and i am supposed to get a delay of 1 sec.I'm using an external crystal of 16mhz and this is the configuration bits that i have used in it.I have configured the timer1 and ...
0
votes
1answer
474 views

Can not jump to Timer interrupt function in STM32F4 discoverty

I made a code to call Timer2 interrupt function like this : ...
1
vote
2answers
143 views

Restart timer for a device

I have a device which needs to be manually restarted (switched off and back on) after every 4 hours or so. I was wondering if there is some device which I can buy or make which does this work for me. ...
0
votes
1answer
743 views

stm32f10x: how to redirect timer output to a given GPIO pin

I would like to programmably send pwm signal to one of the 16 output pins. One way to do this is to trigger interrupt on timer reload and on output comare event, and then to update the corresponding ...
2
votes
1answer
100 views

Using both PWM and Timer2 interrupt in PIC18F25k50

Background I'm working on lead-acid battery charger and experimenting with battery desulfation. I want to draw current vs time graph on graphic LCD and see: how high current spikes I have measure ...
1
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0answers
237 views

STM32 Timer Internal Clock Source

As I understand, the internal timer clock source on the STM32(F4) microcontrollers can be either APB1 or APB2. However, I can't find which timers get which clock. I already found ST AN4013, which ...
2
votes
4answers
227 views

Beats per minute calculator

Basically I want to create a BPM calculator on an ATMega1284. So I have a mic hooked to the ADC already (with potentiometer). I can probably calculate the BPM by getting samples for a while and ...
0
votes
1answer
77 views

Automaticaly switch on/off an (APC) UPS

I need to switch on my APC UPS at 2 AM and switch it off at 8 AM every day. Would like to switch on/off the mains power to the UPS too. I am not an electronics guy, but started to learn and have ...
-1
votes
2answers
356 views

Delay on STM32F4 Discovery not working

I am trying to make a 10 seconds delay function using STM32F4 Discovery board. Unfortunately, it is not working and I don't know why. I have been two days on this problem. Can anyone help me please? ...
1
vote
1answer
48 views

Software timers using hardware interrupt

I have to implement a counter for upto 30 minutes on my microcontroller. However the hardware interrupts maximum time is nowhere close to this. So I think I would be using the interrupt and increment ...
0
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1answer
94 views

An adapter for disconnecting the current after a particular period of time

I want to prepare an adapter which will discontinue the power supply after a particular period of time. The time period will be provided manually using a switch. The time periods are: continuous ...
1
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1answer
125 views

Is there a way to avoid an infinite loop and reduce CPU power consumption when using PIC and timer0 interrupt?

I have made a simple program that runs on a P12F629 microcontroller, using MikroC. I need ...