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.

learn more… | top users | synonyms (1)

0
votes
0answers
16 views

Requesting help with periodic sampling of Capture with PIC18 microcontroller

I am using MPlab C18, and PIC18f4520 to make a motor controller with negative feedback. I measure period using CCP2, which I have reconfigured to use the alternate input pin (RB3), and this uses ...
0
votes
0answers
20 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
votes
3answers
50 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 ...
0
votes
2answers
62 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
126 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
118 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 ...
-2
votes
0answers
10 views

Resetting an arduino with a timer or sth similar [migrated]

I want to run an arduino autonomously - but although i apply a watchdog sometimes the systems hangs and can only be restartet by physically interrupting the power-supply (or hitting reset). So i need ...
1
vote
0answers
26 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
85 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 ...
0
votes
1answer
28 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
vote
1answer
56 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
193 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 ...
0
votes
2answers
86 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 ...
1
vote
0answers
21 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. ...
0
votes
1answer
60 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 ...
0
votes
0answers
29 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
vote
0answers
51 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 ...
0
votes
2answers
72 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 ...
0
votes
2answers
119 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 !!
1
vote
0answers
42 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 ...
0
votes
1answer
45 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 ...
0
votes
2answers
94 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 ...
1
vote
2answers
76 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
votes
1answer
90 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 ...
1
vote
0answers
66 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 = ...
0
votes
0answers
55 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
votes
1answer
142 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 ...
0
votes
1answer
49 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
votes
0answers
144 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 ...
0
votes
3answers
88 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
votes
3answers
102 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?
0
votes
0answers
72 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
votes
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 ...
1
vote
0answers
48 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: ...
1
vote
1answer
322 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
votes
0answers
121 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 ...
1
vote
2answers
272 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 ...
0
votes
0answers
90 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
votes
2answers
239 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?
0
votes
1answer
83 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
94 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 ...
1
vote
2answers
111 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.
0
votes
3answers
450 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) ...
1
vote
1answer
264 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: ...
0
votes
2answers
173 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
vote
1answer
117 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 ...
0
votes
0answers
68 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
128 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
vote
1answer
55 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
1k 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 ...