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 ...

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Update time again with terminal or Bash after bootup

I use my Pi as part of a home automation system, logging and carrying out events according to time. It is connected to a working internet connection, but let's say the power temporarily goes out and ...
4
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1answer
630 views

Using GPU to decode QRCODE

I'm using a raspberry pi compute module and my question is : Can we use the GPU to decode QRCODE ? I am using my own function inspired by the one from QRTOOLS and by doing so the timing is divided by ...
4
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2answers
111 views

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?
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0answers
29 views

Raspberry pi execution time calculated is different on the desktop terminal and command line?

Boot to desktop and boot to command line can be chosen using raspi-config. I decided to do a test to see whether my code will execute faster using the command line interface. How come the ...
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0answers
10 views

Real Time project with Raspberry Pi [duplicate]

I see some disadvantages: Current Linux / BSD kernels for the Raspberry Pi do not support real-time Standard Linux or BSD install includes services that generate lots of overhead No real-time clock: ...
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0answers
23 views

How to make servos not jitter without extra hardware [duplicate]

To control a servo, I'm using this. To summarize it: you use code like this: while True: GPIO.output(pin, GPIO.HIGH) time.sleep(0.0015) GPIO.output(pin, GPIO.LOW) time.sleep(0.0185) ...
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2answers
171 views

Can raspberry pi 2 take more than one input

This is basically a followup question to my previous questions (you don't need to read them to answer it). Primary question is, can a Raspberry Pi 2 take more than one inputs from different circuits ...
2
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1answer
343 views

Raspberry Pi (raspbian) tick rate in HZ

How can I find the Linux tick rate of my Raspberry Pi 2. I have a Raspberry Pi 2 with Raspbian OS. Is it 100 or 1000 HZ ? Can I read it from the command line or a C program ? I want to know this ...
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1answer
42 views

Raspberry Pi project with sound concatenation based on date/time and events [closed]

I'm thinking about making my first Raspberry Pi project and have some questions regarding what I will need to be able to complete this project. The end result should be a sound based machine with two ...
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0answers
35 views

Raspberry Pi real time display circuit [duplicate]

I have Raspberry PI (b+ and 2) and I would like to have Multiplexed 7-segment display (homemade - at least 8 digits). Principle: but I want it runs on different realtime circuit. Simply: I will send ...
0
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1answer
131 views

Some error happened when running a python program on raspberry pi

I want to make a program to display the real time input audio signals in the forms of FFT and Amplitute via a USB audio card in raspberry pi. So it supposes to have a user interface to display the ...
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1answer
2k views

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 a 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 ...
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2answers
84 views

Why is Real Time Software an Issue? [closed]

I just bought a Raspberry Pi 2 B to so I can learn more about programming. I noticed that there are a lot of questions about running real time software on the Raspberry Pi, such as this one: Is it ...
0
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1answer
87 views

Let two RPi's communicate over the internet [closed]

I'm working on a little side project for which I would like to let two Raspberry Pi's communicate. The idea is that they are both connected to the internet and have sensors and actuators (LED, motor ...
0
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2answers
156 views

Can the Pi run an embedded RTOS other than Linux?

I have a hobby project that requires a real-time MCU running an embedded RTOS like embox or something comparable. I know that it is typical for the RPi to be ran with a Linux flavor like Raspian, ...
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1answer
3k views

Does Raspberry Pi 2 support RTOS?

did somone have the knowdlege is new Raspberry Pi 2 is compatibile with Xenomai RTOS? In old version (Raspberry 1) that was a path which make berry to work with Xenomai. I was started reading about ...
2
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1answer
262 views

Raspberry Pi as near real time digital signal processor

I have a Pi with Wolfson Audio Card, running Raspbian with low latency kernel. Is it possible and feasible to use such a setup as a near real time digital audio processor, like a reconfigurable ...
1
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1answer
189 views

Update time whenever possible

The Pi running Raspbian does not have a hardware clock or RTC (serial is being used by XBee) and whenever its turned off and restarted again, the time goes out of wack and we need to SSH in to ...
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1answer
1k views

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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0answers
167 views

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 ...
3
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0answers
3k views

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 ...
0
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1answer
478 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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1answer
150 views

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 ...
3
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1answer
681 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 ...
0
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1answer
444 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
420 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 ...
3
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2answers
5k views

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 ...
9
votes
1answer
1k 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 ...
4
votes
1answer
3k 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] ...
5
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2answers
2k views

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 ...
6
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5answers
21k views

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 ...
2
votes
2answers
2k 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 ...
11
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3answers
4k 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 ...
4
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0answers
1k views

Xenomai RTDM Skins for I2C, SPI [closed]

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 ...
5
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1answer
2k 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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0answers
249 views

Interfacing external device using accurate high-speed clock signal [closed]

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 ...
0
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1answer
210 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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8answers
35k views

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 ...