Raspberry Pi Stack Exchange
Raspberry Pi Stack Exchange

Questions tagged [real-time]

The actual time during which a process or event occurs: "information updated in real time". This topic covers how to control the Raspberry Pi in real time, how to use software in real time, and any other use of the Raspberry Pi in which real time control is needed. Not to be confused with real-time clock.

Real-time computing describes computer systems (hardware and software) subject to a real-time constraint. It must guarantee a reaction within specified time constraints between event (e.g. an interrupt) to system response.

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Is it possible to run real time software?

I know it runs Linux and there are real time patches available for Linux. Would those patches work? Has anybody tried another real-time-os on the Raspberry Pi? The idea is to use the board for regulation and control jobs that are time critical.
Lars Pötter
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Zero-crossing activated relay

How could I go about programming a switch (based on solid-state relay or a triac) that triggers on zero-crossing power? For these not familiar with the subject: Switch 230V power on, when the sine wave of the power line crosses zero - the result is…
SF.
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Does the Raspberry Pi 3 support RTOS?

I am new to the RTOS world. I am planning to use some RTOS on a Raspberry Pi 3 (may be FreeRTOS). Can anyone suggest which RTOS would be good for the beginners? Since they have not released a datasheet on the BCM2837 yet, is it even possible to load…
sandy
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Raspberry Pi for real time video processing

A project I'm working on involves wireless transmission of images from a camera to a host computer in real time. Can the Raspberry Pi be used as a DSP for the camera for image acquisition and pre-processing?
user5610
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How to precisely capture the arrival time of an input edge?

On the Arduino / ATmega328p, the 16-bit Timer/PWM modules have a input capture unit that allows the precise time of arrival for an input edge to be recorded even if the processor is busy when the input edge arrives. (For details refer to the…
AJMansfield
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Setting the time on the raspberry PI - one day out - what gives?

So I understand that the Raspberry PI works some magic with internet servers and whatnot to get its time and that I need to wave some magic dust over the localtime link and possibly /etc/timezoneinfo to get it to work. The thing is - it seems to be…
kmp
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Arm timer in kernel module with precision less than microsecond

Good evening, i'm asking your help, to understand how to use a timer in kernel module to achieve periodic task with period less than a microsecond. I was searching on the web and i've found that exists a Timer (ARM side) that is capable of such…
Flavio Barisi
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How to disable or shutdown NTP daemon?

I am running PI 3 as a standalone system. Therefore, it won't have internet connection and pi's date and time is manually set and Real Time Clock chip is used to keep the pi's date/time current. It works great. However, after running into unrelated…
ThN
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Interrupts on the Raspberry Pi

What are the sources of interrupts on the Raspberry Pi. I currently have the model B, rev. 2.0. Example itop output: INT NAME RATE MAX 3 [ 8 Timer Tick] 20 Ints/s (max: 20) 32 [g, dwc_otg_pcd,…
TheMeaningfulEngineer
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Saving graphs using Matplotlib is very slow

I am trying to write a python Code snippet which creates 24 figures and 9 subplot and saves them in the directory. Its taking around 197 sec to create all the 24 figures and save them. This is implemented Raspberry Pi 3. How could I optimize the…
code_slack
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PREEMPT_RT and RPi Drivers

I'm planning to do some realtime control loop tasks with the RPi. In this post PREEMPT_RT and Xenomai were proposed. I'm thinking about trying PREEMPT_RT, as I'd like to keep it as simple as possible. In the linked post, @Nakedible opposes that the…
fabb
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Setup microphone stream and turn your raspberry pi into a baby phone

I have a "simple" question. I would like to turn my Pi into an audio streaming device for a game, where I need to hear what is going on in a room. So I connected a USB microphone to the Pi and would like to set up a stream now, that streams the…
SebasZil
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Triggering two USB cameras connected with single Pi at the same time

Is it possible to trigger two Cameras connected by USB to a single RPi at the same time with 1 ms latency?
Chitrang Talaviya
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Default kernel preemption vs real time patch?

Is the default Raspbian shipped with the real time patch? I'm using the .config of the default Raspbian installation as a base for a custom kernel compilation. In the section: >Kernel Features -> Preemption Model ( [=y]) The…
TheMeaningfulEngineer
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Xenomai RTDM Skins for I2C, SPI

In another post I read that Xenomai could be used for real-time tasks like control loops. I'd need to implement a real-time task which also talks to I2C and SPI. In this mailing list message I read that the clean way to implement this in Xenomai…
fabb
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