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.
0
votes
1answer
28 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 ...
0
votes
2answers
51 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, ...
0
votes
1answer
33 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: ...
0
votes
0answers
31 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
votes
2answers
60 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 ...
1
vote
2answers
71 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 ...
0
votes
0answers
58 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
votes
0answers
57 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 ...
0
votes
0answers
84 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 ...
0
votes
2answers
90 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
votes
1answer
48 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
votes
0answers
23 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
135 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 ...
1
vote
3answers
101 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
188 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 ...
1
vote
3answers
90 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
320 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
289 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
275 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
187 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 ...
1
vote
4answers
335 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
235 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 ...
7
votes
1answer
82 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 ...
-2
votes
1answer
106 views
Circuit doesn't behave as it should [closed]
I have the following schematic:
The original one (the second one) may be found here: http://www.zen22142.zen.co.uk/ronj/24h.html. Note that the chip shown is a 4060 14-bit binary counter.
The ...
0
votes
0answers
33 views
Pulse extender device [duplicate]
What should I use to extend a 1/2 second GPI pulse that generates out of a cue trigger port twice an hour by a schedule from a Cisco D9850 receiver, to 5 seconds duration or more?
5
votes
2answers
408 views
Problem with 555 timer and 4017 counter
simulate this circuit – Schematic created using CircuitLab
I'm attempting to make a circuit that flashes each LED sequentially. So far my 555 timer works just fine and gives me a pulse ...
3
votes
4answers
304 views
Is it possible to have multiple ISR routines for a single timer in micro controller?
I have doubt that micro controller will support multiple interrupt routines for a single timer.
For example, single timer which interrupts at 5ms, 10ms, 1s etc. In my design I am using 3 timers: one ...
2
votes
2answers
256 views
Modify circuit to turn motor on/off multiple times per switch press
I purchased a timed air freshener kit which makes the motor spin when the switch (SW1) is pressed. I have created a schematic based on the diagram in the instructions (pdf).
simulate this ...
18
votes
3answers
663 views
How to synchronize two microcontrollers to micro-second accuracy?
I need to synchronize two micro-controllers so that they can measure the speed of propagating waves. The time delay measurements need have microsecond accuracy (error less that 1/2 of a microsecond).
...
0
votes
1answer
420 views
555 Timer 74LS192 IC Circuit
Our instructor gave us the assignment of creating a working schematic using a 555 Timer and a 74LS192 IC using 9 LEDs. The 9 LEDs will blink counting in seconds particularly 9 seconds then it's going ...
1
vote
2answers
734 views
High resolution system timer in STM32
I have some software running on an STM32F103 (I'd also like to be able to use the F4) where I'd like to be able to 'timestamp' events (such as interrupts on external pins) to the nearest microsecond ...
2
votes
1answer
111 views
Accurate Timer, follow up and How to?
In the question: Very accurate time measurement, Rocketmagnet show a circuit that is exactly what I need for a cub scout pinewood derby race track timer. I want to be able to dedicate a timer to each ...
-1
votes
2answers
124 views
Understanding timers
I'm studying timers for use in scheduling and embedded systems but I don't understand the detail, does the time count upwards or downwards? Is the timer like a hardware timer like the ones we learnt ...
0
votes
2answers
48 views
Should I use Counter1 to record time series data?
My Atmega328 will record data from an external sensor at around 100Hz over several minutes. Communication is done through I2C requests to the sensor. I need to store the time of measurement (relative ...
0
votes
1answer
42 views
Implement IR protocol using only one timer
I want to implement the transceiving part of an IR protocol for my Samsung remote on an nRF54822, using an ARM Cortex M0 core. The protocol is very much like the NEC Protocol, and is using a carrier ...
3
votes
1answer
299 views
Calculate exact timer frequency for ATTiny
Trying to wrap my head around these overflow timers for the ATTinyx5 (45 in this particular case). I seemed to have a great handle on it with the ATMega328 but I cannot get it to work the way I want ...
3
votes
1answer
180 views
Using Prescaler above 64 on ATTiny45
I'm trying to setup Timer0 on an ATTiny45 using the arduino-tiny core. TIM0_COMPA_vect works fine for prescalers 1,8 and 64, but 256 and 1024 cause the ISR to not fire. I am running the chip at 1MHz.
...
2
votes
0answers
116 views
ATtiny85, timer 1B does not work if COM1A1|COM1A0==0
I read the datasheet, and checked http://www.avrfreaks.net forum, but I cannot understand why on an ATtiny85:
...
4
votes
2answers
352 views
Building small, low-power pedometer/odometer with memory and time/date log
Background
I'm a researcher looking at the use of personal tracking devices and apps (like Strava app or Fitbit device) for cycling. At the moment I'm designing a simple experiment where I want to ...
0
votes
4answers
229 views
Timer on PIC18 not getting close to desired interrupt period time
I tried to setup Timer0 on a Microchip PIC18F46K22 so that it will trigger an interrupt and toggle an LED. However, it takes at least 42 µs for the LED to toggle.
At an increment rate of Fosc/4 (= 8 ...
2
votes
1answer
94 views
How do I momentarily ground a 3.3V signal (with a pull-up resistor) when power is first applied?
I need to momentarily ground a 3.3V signal that has a pull-up resistor on it when power is first applied.
This is feasible using a microcontroller or a push-button, but is there a "passive" way to ...
24
votes
4answers
1k views
Why would a modern digital clock rely on mains frequency?
I am in the military, stationed in Djibouti, Africa. We generate 240V/50Hz power on base, but some buildings also have 120V outlets, which I assume is transformed somewhere else on base, probably at ...
-6
votes
2answers
959 views
How does the 555 timer IC circuit work?
As a beginner to electronics I'm having a tough time understanding circuits that have a combination of different components, including the following timer circuit. Its based around a LM555 timer IC. I ...
5
votes
3answers
409 views
five month countdown timer circuit?
I'm a beginner in electronics, so I just have an idea in my head and don't know how to actually make it. I want to make a countdown circuit, for an event in next 5 month. The display format is like ...
7
votes
4answers
274 views
Can I achieve a one shot button without a 555?
I have a complex circuit, but my problem only relates to one small part.
I have a relay, which is energised by pulling the low side low using an NPN. I would like a pushbutton to operate the ...
3
votes
1answer
313 views
PIC interrupt based soft UART timing trouble
I've tried to implement a software UART on a PIC18F452 using TIMER0 interrupts and I can't get the timing working.
I'm using MPLAB ASM for compilation and the PICkit2 for programming.
...
3
votes
2answers
346 views
Use PWM and ISR at same time on AVR
Is it possible to use AVR PWM outputs and ISR interrupts at the same time?
I've got a project I'm trying to do on an ATMega328P and I need 3 PWM outputs but ALSO need to be able to use ISR interrupts ...
1
vote
1answer
113 views
Difference between Max Interface Clock and Max Timer Clock?
I am trying to use a timer from STM32F4 with ARM Cortex-M4 chip. I need to get the maximum frequency out of that timer for my ...
0
votes
0answers
420 views
stm32f2xx external clock source for timer
I trying to use a timer with an external clock source on a stm32f207ZE microcontroller.
But it isn't working. Here is my code:
...
4
votes
3answers
86 views
Creating a Sequenced Array of 3 Mosfets with Adjustable Timings
I am comfortable with rudimentary 555 circuits and other basics, but I have something a little bit beyond me now.
I need to have three separate mosfets A, B, and C all turn on and off in sequence. I ...
