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.

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RaspberryPi Timer Interrupt with WiringPi

What I'd like to do is to create an interrupt one a timer expires after 1 ms ... 100 ms. It doesn't even have to be very accurate. Working with microcontrollers I'm used to start a timer say in ...
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Is it possible to use GPIO's simultaneously?

I'm interested in using raspberry to control a number of brushless motors. PWM should be executed parallely to work in needed rate. As far as I've heard, RPi provides only consequent requests to ...
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Best approach for real time operating system on Raspberry Pi

I need to use Raspberry Pi with a real time operating system. Of course, I want the best solution. I've searched some options, including custom kernel compilation, ready to install RTOS. So, which ...
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tsl235 and the RPi

I'm trying to get the tsl235 (https://www.sparkfun.com/products/9768) working with the PI and the bcm2835 library (or without it, just using a simpler mmio) and while the operation of the tsl235 ...
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1answer
100 views

DHT22 code not working (datasheet instruction and xenomai)

I'm trying to read temperature form DHT22 using Raspbian patched with xenomai real time system. I'm following steps of datasheet page 4 using gpio4. . the circuit is correctly wired(I can read with ...
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Real-Time Computaion! Processing Speed Problem!

I am pretty new to the c++ and raspberry pi. I am trying to run a real time sensor motor control with the help of Raspberry pi, using cpp. I am sniffing the sensor data through Ethernet and sending ...
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1answer
396 views

Raspbian - Real Time Kernel does not boot

I am trying to make a Raspbian kernel to support real time. To do that I cloned the latest kernel from raspbian github repository and applied the Real Time patch for 3.10.25-rt23 ...
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146 views

Chrony 506 Cannot talk to daemon

I'm having trouble configuring chrony to sync the time between my raspberry pi and a desktop computer in an isolated network. My raspberry pi's chrony.config file looks like this: server master ...
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2answers
186 views

Software PWM as kernelspace module?

Has anyone tried doing a software PWM on the GPIO pins via a custom written module in kernel space? Wouldn't want to reinvent the wheel, so if there where tries, please forward me to them. Will ...
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Default kernel preemption vs real time patch?

Is the default Rasbian shiped with the real time patch? I'm using the .config of the default rasbian instalation as a base for a custom kernel compilation. In the section: >Kernel Features ...
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602 views

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 ...
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1answer
2k views

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] ...
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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 ...
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5answers
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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 ...
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2answers
1k views

Raspberry Pi to iPhone Audio Streaming

I am trying to figure out how to get as close to real time streaming as possible from Raspberry Pi to an iPhone (more particularly just an HTTP stream so iPhone or Android could use it). The Raspberry ...
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3answers
2k views

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 ...
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1answer
880 views

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 ...
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1answer
1k views

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. ...
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181 views

Interfacing external device using accurate high-speed clock signal

I need to interface device using specific synchronous protocol that requires clock signal within 1..2MHz. Period instability shouldn't exceed 10%. Also, in certain condition protocol requres clock ...
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179 views

Should I buy an external device to store data on

I'm planning to use my pie 24/7, but SD cards are not made for this. Because of that I want to reduce the read and write jobs on the card so it will last longer. There are several options to do this; ...
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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 ...