Questions tagged [timer]

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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54 views

HM-TRP radio module works at 56K data speed but only in delayed chunks

I created the following setup: I created one circuit in which the PC connects to an HM-TRP radio module via a max232 DIP IC. This circuit for the test is the master to all devices and sends a 16 byte ...
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55 views

What keeps a delay-off timer energized when you cut off the power?

I've come to understand the function of the delay off timer as follows: When it is energized, it instantly changes its contacts. And when you "de-energize" it, it delays for a preset time and only ...
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177 views

NE555 Circuit stops working after random time

i finished my NE555 circuit and created some pcbs. After a few attempts i could get the circuit working, and tested it successfully. I placed my circuit between a 12V 1.5Hz square wave signal and a ...
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318 views

555 Timer Circuit Simulation Generates an Error

I simulated the circuit below: The expected output is a 50% duty cycle 40 kHz square wave but the simulator (MultiSim) generates an error and doesn't compile. The error message is as follows: "A ...
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1answer
99 views

Obtaining data from parallel port without the “phantom power” problem

After making failed circuits in the past, I learned that the cause is that the parallel port was producing "phantom power" (aka powering the circuit). This is because I plugged my circuit into the ...
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68 views

Serial baud calculation without using serial interrupt - 8051

Here's the situation. I have a project which utilizes multiple sensors and connects to another unit through standard UART (8N1). Because no data needs to be missed from any device, I made the ...
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963 views

STM32F7 + TI ADS127L01: SPI with DMA circular mode + Timer IC for data ready signal + CRC

I've connected a TI ADS127L01 to the SPI2 of a STM32F746 mcu via SPI2 and Timer 2 Channel 4 input capture for the data ready signal. As soon the data ready signal is captured, the SPI TX DMA (which is ...
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2k views

STM32F7 Timer and DMA

I'm currently trying to adapt the example project TIM_DMA of the F769I_EVAL to the STM32F746G discovery board. I'm quite new to STM32 and this might be an obvious error. The code creates a timer and ...
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41 views

Switching timer delay, non accumulative

I am trying to build a 555-timer that delays the switch of an input signal, both ways. When input goes high there should be a delay before output goes high, when input goes low there should be a delay ...
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1answer
87 views

Adding Transistor to Maintain Voltage Across Proprietary Switch

So, I purchased a camera trigger that moves the camera and then triggers the shutter. I wanted to change when the camera shutter was triggered so I purchased a cheap eBay delay timer relay. I knew the ...
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240 views

Transistor for 38kHz IR pulse amplification

I am trying to build a timer circuit in which I will send a modulated 38kHz (almost) signal to an IR Receiver (TSOP38238 in Arduino Nano) and I want to amplify the square wave to the IR Led to ...
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258 views

Problems with ICP Atmega328p

I am trying to use ICP (Input Capture Pin) functionality of ATMEGA328p (Arduino Uno board) and somehow it does not seem to work. I have connected a switch to ICP pin PB0 in this case, and want to ...
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47 views

Random timer windows on a DC circuit

Are there any components/devices out there (available via RadioShack, or some other vendor) that behave as follows (or similarly): When a signal/voltage is detected, a random (and preferably ...
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59 views

Embedding python interpreter in the TM4c1294XL

I have a python file that I want to run on the board. Hence I want to embed the python interpreter (written in C) in the board. I managed to write separate C project that runs the Python file. It ...
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1answer
651 views

power on power off pulses to two seperate controllers

I would like to request a circuit where a 500 ms pulse is sent to one rail when 12 volt power is supplied and another 500 ms pulse is sent to a different rail when power is turned off. 555 is the way ...
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170 views

Generating a short pulse after a delay on ATmega 328/P

I am trying to use one of the hardware timers on the ATmega 328/p (arduino uno) to generate a short pulse some number of microseconds after receiving a pulse on an input. Currently my code looks like ...
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306 views

How to add Lptmr ISR to Interrupt Vector Table for Freescale K60DN board, ARM Cortex M4 Processor

I am attempting to use the low power timer of the Freescale K60 board. I have an interrupt handler written, and now do not know how to add the address of the handler to the interrupt vector table ...
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272 views

Delay-off circuit for h-bridge motor control

I'm looking for the easiest way to generate a variable PWM signal (set by hardware) without a microcontroller for a set amount of time when a microcontroller is turned off. The H-bridge (image below) ...
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300 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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692 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 ...
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1answer
100 views

Want to replace push-button with IR receiver

In the diagram below I want to replace that push-button switch Sw1 with IR receiver, I tried a lot with different combination with IR receiver and tried with transistor but I failed, so, please how ...
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1answer
247 views

scheduling time in AVR

I have a board that have 3 relay. I have 3 function for Set / Reset / Toggle a relay that get a special relay number and do action on that as below: ...
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1answer
692 views

Timer causes UART problem

I have a problem, found on both ATMEGA1284P and ATMEGA2560. I have set a 16-bit timer in CTC (tried both Timer1 and Timer5) to give an interrupt every 1ms so I can increment a 32-bit volatile time ...
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3answers
303 views

555 timer not switching at threshold voltage

This is a 555 timer circuit which is supposed to generate two short pulses, back to back, at a regular frequency. The top 555 is configured as astable to control the frequency. It feeds the first 555 ...
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1answer
53 views

555 timer question

R1=500k variable resistance R2= 10k when the timer's operation time is 5sec, R1 86.7k What is the operation time when 4V is applied to 5(red point)? im student, so I would very appreciate it if you ...
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350 views

setting timers mode 2 autoreload 8051

I have to create a square wave of 200 micro seconds By using the auto reload timer I have found a3h by doing the following calculation 255 - 92 (decimals) = 0xa3 so i set the timer this way : mov ...
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104 views

What type of capacitor do i need for this delay?

I installed a set of LED RGB foot-well lights on my truck. When they turned on, they have a small half second glitch before staying constant. I believe that this is because the LED RGB controller ...
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1answer
37 views

producing a continuous sound using a timer

I'm looking to produce a pure sound on one frequency to be played via a timer to come on at intervals over a six week period. this is for an undergrad dissertation. would an arduino work and could it ...
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1answer
74 views

Counting slow to fast in a microcontroller.(Ramp)

I want to make an increment(++) to a variable initially slowly then speed up linearly. For example, using a timer interrupt(every 1 sec) in increase the variable x by 1.so at first variable get ...
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1answer
188 views

building a random timer circuit that will delay from 0 to 3 sec after trigger input relay output

need some help to build a random timer circuit that will delay from 0 to 3 sec after trigger input relay output Have looked at a number of 555 circuits but no monostable or astable ic seems capable
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420 views

Constant power supply with countdown timer triggered by a momentary switch

Can I make a 1 or 2 NE555 timer delay switch adjustable module from eBay,or any other simple components ? Momentary switch closes = power ON and start of a countdown timer of 0.3s. Mentary switch ...

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