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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61 views

Simple question (I guess): 555 timer

I want to know if it's possible to have a push button so that when it's activated, it turns on my 9 volts circuit for 10 minutes and then turn it off. Also, I don't want this circuit to consume ...
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1answer
51 views

Low power timer circuit for solar tracking

I'm making a solar based device but it needs to be aligned according to sun's position in sky , the whole assembly needs to move around 11 degree/hr. So I was thinking of using a timer circuit (low ...
4
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3answers
171 views

Calculating time spent by a function in Microcontroller Applications

I would like to write a simple profiler for my STM32F100VE microcontroller. I have seen that I can include time.h and based on the c standard functions I can use it, but I was confused about ...
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1answer
61 views

How to measure distance using radio waves? [closed]

Have you seen http://www.youtube.com/watch?v=CvZ4_SIAxDY I need a similar circuit to do the same. There are two module. Module A and B. A sends to B and B returns signal to A. How to find the time ...
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1answer
44 views

555 timer duty cycle

In order to increase the Duty cycle span of a 555 timer above 50% I should connect a diode. the equation of duty cycle without diode is D=(R1+R2)/(R1+2R2) but when I add the diode what is the exact ...
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2answers
96 views

The 555 timer (astable mode)

how can i edit the 555-timer astable mode in order to get a larger span of duty cycles passing by values below 50%? D = tH/T= (R1 + R2)/(R1 + 2R2) this is the equation, by changing the values of R1 ...
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0answers
89 views

Calculating a delay of 1 second with a PIC 16F877A

I got a PIC Micro controller with a 4mhz crystal. I established(hopefully right) that 1 cycle requires 1 micro second to complete. As a result to accomplish a 1 second delay, I need to use 1,000,000 ...
3
votes
3answers
293 views

Software delay vs hardware timers [closed]

Working with a microcontroller, on which exact conditions should we choose between Hardware timers and Software delays on an Embedded Controller? I have seen articles which do emphasize on use of ...
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2answers
58 views

Ideas on building a water sensor power switch

I would like to build a water sensor power switch. A device which completes the circuit of an outlet adapter when the water sensor has detected water. I have a very simple idea about this little ...
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3answers
79 views

How to trigger something once a day [duplicate]

What would be the right thing to use if I want the base of a transistor to be high for 12 hours and low for 12 hours? I ask because I would like to make a circuit that regulates temperature in a ...
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0answers
40 views

Latch Switch with timer relay

So my basic operation of things are: -A button will be pressed -A timer relay will be triggered and will run a high power motor. -The relay would turn off after a predetermined time. -The button will ...
3
votes
3answers
161 views

Using 555 to generate square signal with fixed duty cycle / variable frequency

I am attempting to design a circuit whose output is a square wave with the following properties: Fixed duty cycle, as high as possible (let's say 99%) Variable frequency, between 0.2 - 20 Hz (I'm ...
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1answer
74 views

What is the difference between Timer0 and Timer2 in AVR

I'm using ATmega32. This two timers looks very similar. What is a difference between them? When should I use Timer0, and when Timer2?
1
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1answer
78 views

STM32 Timer to control GPIO

I'm trying to output a slow clock (4kHz) on an I/O from the STM32F0. I'm wondering what the advantage is (if any) of using one of the timer pins to output this clock vs toggling another GPIO on the ...
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votes
2answers
85 views

Toggling on and off 220V power

I have a 9V 555 timer circuit and I want to use it to automatically turn on and off a 220V water pump. What can I use to connect the timer and the pump? Is there like a transformer or something?
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votes
2answers
130 views

How can I wake up an ATtiny84 microcontroller at specific time of the day?

I am trying to create an alarm that wakes up at a certain time and does a series of instructions. To set the times that it wakes up, I am going to use the headphone of an Android device to send ...
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0answers
20 views

556 dual timer to produce a biphasic wave form, and possibly an assymetrical biphasic? for muscle stimulation [duplicate]

I am needing to make a 35Hz biphasic asymmetrical output for a muscle stimulation device. I have a 556 dual timer and am familiar with the 555 timer, but entirely sure how to utilize 556 for biphasic ...
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0answers
55 views

STM32F207 timer2 output toggle

I am trying to get clock signal out of timer 2 channel 1 on my STM32F207ZGT6. I wnat to use the compare match to toggle the pin, but nothing I programm seems to get any kind of signal on that pin ...
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3answers
155 views

Can you make a waveform asymmetrical with the 555 timer?

Using a 555 timer how do we output a biphasic square wave instead of a monophasic? Is there any way to make it asymmetrical? If not are there any other devices or circuits to use to make an asymmetric ...
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2answers
173 views

PIC:how can we get 1 ms interrupt using 16bit timer?

I am using PIC24FJ256GB106 controller.I am setting configuration bit for internal frequency to FNOSC_FRCPLL. I have confusion to this configuration bits that Am i getting 8MHZ or 16MHZ or 32MHZ ? if ...
0
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1answer
68 views

555 timer multivibrator charge and discharge

With this kind of connection I expect 555 to run as a multivibrator. As far as I understand the discharge of the capacitor should be via R2, while charge of the capacitor via R3 and D1. => discharge ...
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1answer
111 views

PIC18 microseconds counter

I want to count microseconds between timer's ON/OFF. My FOSC is 48 MHz. I figured out timer1 would need to be initialized like (I'm programming in mplab): ...
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1answer
86 views

Deferred callback manager / software timer library for PIC32

I'm looking for a software timer library for embedded systems, especially PIC32, free or commercial. I'm NOT looking for a full-blown RTOS with threads, I/O, etc. - just for the software timer ...
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2answers
90 views

How does this synchronizing/edge detector logical diagram work?

This is the logic diagram for a MCU that allows for an external clock option via Tn. This clock can be used as the source for clocking an internal timer register. ...
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2answers
71 views

Prescaled Timers Problem

I'm using a attiny2313a, and I'm having a lot of trouble figuring out what's going on with the timer. It's very simple, yet it simply refuses to work. I have a 16Mhz clock. When I put in a 1024 ...
5
votes
1answer
206 views

is 555 timer good to generate 20MHz clock?

I am looking for a way to generate 10 to 20MHz TTL-compatible clock signal. I used something like microchip unit to produce clock signal before in school but I didn't use any other way to generate ...
4
votes
2answers
198 views

MSP430: how to let the timer ISR interrupt the Serial RX ISR?

I am working on a MSP430 connected to the PC via serial. The MSP430 also communicates with some other boards using a bit-banged serial interface. I'm using the timer peripheral to bit bang the serial, ...
0
votes
1answer
80 views

Holding voltage high, for monostable 555 timer pulse

First I'll mention I am an amatuer in electronics and therefore I ask for easy to implement answers. Thanks. Straight forward to my question: I want to know if there is a simple (and cheap) way to ...
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2answers
406 views

How to understand the functions of a Therm-O-Disc 12S20 H24V?

I am an electrical novice and have a Therm-O-Disc 12S20 H24V (original image) relay that I'm attempting to understand. The only meaningful documentation I've been able to find is this, 12S, 14S, ...
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1answer
91 views

Interrupts and Arduino EthernetShield

I'm in need of a little guidance in a project I'm working on. Basically, I'll be using two arduinos: The first one will have: 1 RF Link Receiver (linke here: ...
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0answers
58 views

Simple doorbell delay (add-on)

We have a new office doorbell with a pushbutton that rings a buzzer for as long as the button is held down (i.e. a simple circuit that is closed by the button). The buzzer sound is really "angry", and ...
0
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2answers
474 views

What is the difference between TCCR1A and TCCR1B [closed]

I had an error in the configuration of PWM for the atmega8 because I didn't set my register properly. But I thought that Timer 1 is timer 1, no matter is TCCR1A or TCCR1B. Why can I set all the timer ...
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2answers
422 views

Toggle OC1A, OC1B and OC1C using timer in CTC mode

For most AVR MCUs for each timer they got 3 dedicated pins (eg. OC1A, OC1B and OC1C) that can be toggled automatically when the counter reaches the so called top value in the corresponding 3 registers ...
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0answers
187 views

PIC:how to blink LED using timer delay in pic24fj16ga002?

I am using pic24fj16ga002 controller.I am calculate delay using timer3.I am choose internal ocs. with PLL enable(FNOSC_FRCPLL) so its 32MHz frequency.I am using Prescale is 8. my function for delay ...
0
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0answers
136 views

AVR High resolution 4 pin synchronised PWM

I am trying to develop a micro stepping stepper motor driver with an ATTiny45 and a L293 H bridge and am currently prototyping the algorithms using an ATMega168 and the L293. For good quality micro ...
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0answers
312 views

555 Temperature Controlled PWM

I am trying to build a temperature controlled 555 circuit to drive a cpu fan (used for cooling my entertainment center) I built this using slightly different diodes and MOSFET, and it works great ...
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2answers
139 views

Does Arduino SPI use up a timer

I plan on using a barebones Atmega168 running an Arduino sketch to drive two stepper motors and a heater. To interface with the steppers and heater I want to use 4 PWM pins. I will also have an SPI ...
0
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1answer
97 views

AVR Timer for PWM and interrupt?

I am developing a system that needs to drive 4 stepper motors through 4 dual H-bridges, for each phase of movement the AVR will receive SPI messages stating how many steps each motor should do and ...
0
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0answers
41 views

What is the alternate for Data Watchpoint and Trace Unit (DWT) in ARM Cortex A9 ?

I understand there is no Data Watchpoint and Trace Unit in an ARM Cortex A9 processor. So what is the substitute in A9? My intention of using it is to know how many cycles a specific function is ...
3
votes
2answers
259 views

How to compute Timer1 period?

I'm trying to configure Timer1 of a pic24h to 1ms per timer tick but don't seem to be able to get the math to match my results. I have a 20MHz external oscillator (with a 1M resistor in parallel for ...
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3answers
131 views

Limit Number Of Pulses From 555 Or Similar

I need as small a circuit as possible that can produce 2 pulses (say maybe 200 milliseconds long and apart) when I press a button. My thought was to use a 555 timer and set it up for my desired pulse ...
3
votes
1answer
799 views

arduino : delaymicroseconds()

How does the delayMicroseconds() function works. From what I understood the prescaler of timer0 is set to 64. For a 16MHz clock gives 4.0uS per count. I am a bit confused on the math to get to 1uS ...
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3answers
131 views

555 Timer Triggering Too Easily

I've got a 555 timer being powered by a 5v rail that is isolated from the 3v rail running a motor driver, which runs a motor. The 555 is only supposed to fire when it gets the signal from a 38khz ...
3
votes
1answer
1k views

PIC: how to set timer0 to give an interrupt at every 1 sec?

I am programming a PIC18F67K22 and I've set it to use a 16X4Mhz Internal RC oscillator with PLL enabled. -High level interrupt on TIMER0 overflow -I am using ...
5
votes
3answers
380 views

PIC Microcontrollers, ambiguous quiz questions

I am taking a course in micro-controllers (PIC). I recently took a quiz but i am having hard time convincing my teaching assistant that the quiz he made is ambiguous as hell. What would your choices ...
2
votes
1answer
902 views

16-bit timer of ATMega: How to calculate timer count?

I try to use the 16-bit timer of ATMega on each midi clock tick. A beat has 24 midi clock ticks. So e.g. 60 beats per minute = 1 beat per second = 24 ticks per second. How can I set the timer for x ...
7
votes
1answer
249 views

Simon Says without Microcontroller

I'd like to create the classic game of Simon Says utilising nothing but logic circuits, LEDs and ICs, no Microcontrollers like the Arduino. I would like to use 4 LEDs and 4 Tactile Switches for this ...
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4answers
927 views

Delay function in ARM programming

I have just started programming on ARM, I had some experience on AVR but not that much. The question is probably too trivial but the material about ARM is too little on the net... sorry anyways. I ...
3
votes
2answers
501 views

Time Delay Relay: output = HIGH until triggered, then return HIGH after interval?

My goal is for a button press to temporarily disrupt the input voltage (120VAC) for a specified interval (around 10 seconds). Ideally, I'd like the interruption of voltage to coincide with the ...
8
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1answer
139 views

Missing Q11 output on 4060

Is there any reason why Q11 is left out on 4060 IC? I've read it was done to extend the max pulse time (highest clock divider) but why was it done on Q11? Why not Q12 and therefore have a full 8-bit ...