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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.

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insmod with kernel module starting one-shot hrtimer locks up raspberry pi [closed]

I'm doing some early work towards building a kernel module that will be driven from a hrtimer to take telemetry readings. For now I'm just trying to arm a simple one-shot 2-second timer using hrtimer. ...
Denis's user avatar
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0 answers
23 views

Implementing Precise Timing between values with Raspberry Pi and 16-bit DAC using py-spidev

I want to send values from an RPi to a DAC in order to generate an analog signal. The DAC is 16 bits, and I'm using the py-spidev library. Let's say I have a pre-prepared list of 1000 16-bit values ...
Thomas1234's user avatar
0 votes
2 answers
56 views

Have Pico turn lights on at sunset and turn off at 2am next morning

I am still new, but trying to learn. i have been piecing this together, and i'm not getting anywhere. i hope this can be done easier then what i have. the end goal is have the pico get the current ...
AmongTheShadows's user avatar
0 votes
0 answers
27 views

Issue with running multiple processes on a single webcam with Raspberry Pi 4

I have a Python program that utilizes threading to run multiple processes on a single webcam. The code works perfectly fine on my laptop, where it can run different processes simultaneously on one ...
JazzSlign's user avatar
0 votes
1 answer
85 views

Which daemon or process updates /sys/class/thermal/thermal_zone0/temp?

Just curious... been exploring the RPi H/W... can't escape my embedded device-driver "down on the bare metal" past... in that vein I noticed the value in ../thermal_zone0/temp is always ...
Bear Metal's user avatar
0 votes
1 answer
101 views

SOLVED Raspberry Pi 4 missing reverse ticks from AB encoder

I posted this on stack exchange, but it isn't getting much traction so I'm posting here, hopefully someone has run into this before! I am writing a program to control a robot in C using a raspberry pi,...
Zico's user avatar
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3 votes
2 answers
297 views

Raspberry Pi network time, and accurate time for astronomy Data taking needs, at a loss

Does anyone know how to get network time for collecting data using Raspberry pis with no backup battery. Regular googling has gotten me things that do not work. They are Pi 4B with 4GB or 8 GB of RAM ...
strange_octopi's user avatar
1 vote
1 answer
142 views

Measurement in realtime Raspberry Pi 3

I have written a script in python in my Raspberry Pi 3, to get and plot data in real-time from an ADC. The problem is that the data is not time accurate. I want my data to be read once per second or ...
lesandromarteniz's user avatar
0 votes
0 answers
141 views

Logging data from High Precision AD/DA board using Raspberry Pi 3B

I have a High Precision AD/DA board from waveshare with Raspberry Pi 3B (running on Raspbian). With this setup, I get a sampling rate of above 20KPS at my terminal display. However, I can write only ...
Varun Dhankhar's user avatar
-1 votes
2 answers
427 views

How will raspberry PI handle having Daylight savings time locked on

Congress has passed a bill to lock daylight savings time on. How will the PI handle this. What I mean by this is how will the PI know to use the "permanent" daylight savings time?
user2312943's user avatar
1 vote
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379 views

Trying to plot the ADC values from the PICO similar to what an oscilloscope displays. Just scrolls to the left right now. Total Python newbie

#!/usr/bin/python #Python 3.7.3 # Attempting to plot the ADC values coming from the PICO # Program contains only necessary lines of code for testing plot routine # The Raspberry PI Pico is connected ...
R Bowles's user avatar
1 vote
1 answer
378 views

What's the minimum Raspberry Pi that can display the output from the Raspberry Pi camera at 30fps in real time?

Setup: A Raspberry Pi of some kind (TBD depending on answers to this question) A Raspberry Pi camera of some kind (TBD depending on answers to this question) A 1080p television, that will be ...
Mark Raymond's user avatar
0 votes
1 answer
56 views

Process in real time

I am building a Pov Display using Raspberry pi 4 and a code written in Go. The raspberry pi has a sensor (btn) to know when it displays the code. The problem is my raspberry won't execute the code at ...
0ussama's user avatar
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1 vote
1 answer
555 views

Duplicating audio in pure ALSA for playback on local device and streaming via trx

I am trying to achieve a multi-room audio setup in my house using Raspberry Pis. How can I get VLC playing simultaneously out the local headphone port while also streaming it to other devices via trx? ...
michaeljtbrooks's user avatar
0 votes
1 answer
124 views

real time faces bluring with pi zero [closed]

I would like to know if the Raspberry Pi Zero is capable of running deep learning facial recognition and blur faces in real time. If not, what kind of portable device is able to do that?
Pi-R's user avatar
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4 answers
596 views

RPI 0w: automatic timezone syncronization

Is there in Raspberry Pi some setting for automatic timezone synchronization? Maybe some application that can set local timezone on Raspberry Pi? Let's say, I send device to client, after he switches ...
Rougher's user avatar
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3 votes
1 answer
3k views

Real time + High frequency ADC data reading with Raspberry Pi 4

I need to acquire a signal at a minimum sample rate of 10 kHz and processing it real-time using a Python code. Since Raspberry Pi only reads digital signals I get an ADC (High Precision AD/DA Board ...
Tagalog's user avatar
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0 votes
1 answer
141 views

Best approach for smooth 1kHz SPI output

I'm building a raspberry pi project that focuses on outputting analog signals through a DAC connected via SPI. For now, I only need the outputs to be updated every millisecond. I'm testing on a pi3 ...
schmop's user avatar
  • 179
2 votes
1 answer
180 views

How to use ntp time as default time while using Raspberry Pi as a gateway?

I am using Raspberry Pi 4 as a gateway to my esp8266 devices. I have connected ethernet to Raspberry Pi for internet connection. It works fine. I want to generate NTP time in my ESP8266 device. When I ...
Pratik's user avatar
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0 answers
125 views

50 ksps ADC for Raspberry Pi 4

I need to capture 4 Analog signals at a sample rate close to 50ksps. From some posts I have read that this would be unfeasible through SPI or I2C. Is there any recommended ADC chip or breakout board ...
Juan David Galvis Sarria's user avatar
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0 answers
488 views

Is Raspberry Pi fast enough for realtime video processing?

I want to use Raspberry Pi 3 B+ on my RC airplane for a realtime image classification task. Airplane will be flying at an altitude ranged between 10-30 meters with a airspeed of 15m/s. What I need is ...
Ahmet Taha's user avatar
2 votes
1 answer
648 views

socket: Address family not supported by protocol error on raspberry pi 3b+ with xenomai

I have been trying to run the xddp-label.c example as given in the xenomai documentation on my raspberry pi model 3b+ with xenomai patched kernel. I can compile the program just fine, but when I try ...
Yousousen's user avatar
0 votes
1 answer
136 views

Does Python Get Interrupted When Running on PI?

I have seen seen in many places that the Raspberry Pi does not really work well with realtime control, but I am wondering if reading from input pins can be interrupted by the operating system. In ...
Startec's user avatar
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1 vote
1 answer
191 views

Is it possible to have a Raspberry Pi work like a much faster arduino

Let's imagine you have a real-time problem that you can solve with the Raspberry Pi hardware but you need something much faster than an Arduino. Is it possible to bypass the OS of a Raspberry Pi to ...
Camion's user avatar
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1 vote
0 answers
77 views

How to make it run without internet connection? - what part of code keeps it from running?

My RBPi zero has a spotty reception close to the door where it keeps monitoring registered phones on bluetooth and trigger the door opener. What are the options to make it work without/irregular wifi ...
Paolo's user avatar
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1 vote
2 answers
68 views

Manual time - no time server on network

I am a high school teacher and I'm trying to set up raspberry pi's for use in lessons. I've had to manually configure them to connect to our enterprise network but I'm informed the network doesn't ...
Kris's user avatar
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0 votes
0 answers
1k views

Raspberry pi ntp client fails to sync on network master clock

I have a pi3B+ with stretch. I am trying to sync its clock using a network master clock (a pc set as ntp server) through direct ethernet connection. I can't see my server synching the pi. I followed ...
livio's user avatar
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0 votes
0 answers
375 views

Lagging/freezing

We are receiving signals from hardware components that we need to measure very precisely down to the millisecond. It is all working very well until a minor freeze occurs roughly about once every 3 to ...
php_nub_qq's user avatar
1 vote
0 answers
1k views

Access Timer Interrupts in Raspian

I want to write a C program that runs some code at a fixed interval (somewhere between 200us and 1ms, TBD). Is it possible to use the hardware timer interrupts to execute code without resorting to ...
newothegreat's user avatar
0 votes
1 answer
222 views

Display most recent image in folder on monitor

I currently have a receiver system that downlinks real-time images of earth from a weather satellite to a Raspberry Pi, where it then stores them as jpgs. What I am looking to do is automatically ...
Damian Hackett's user avatar
0 votes
2 answers
94 views

Why is my code not working between time hours?And what should be done if im using PIR sensor ,what is the change that should be done in this code [closed]

import RPi.GPIO as GPIO import time GPIO.setwarnings(False) GPIO.setmode(GPIO.BOARD) GPIO.setup(3,GPIO.OUT) #Define pin 3 as an output pin while True: if(time.hour(18)&&time.hour(5)) #...
Haerriz's user avatar
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0 votes
1 answer
2k views

How to know the buffer size of a Raspberry Pi 2 b?

I would like to know the size of my I/O buffer (defined as the queue where the packets arrive, e.g. from internet, and wait to be proccessed). How could I find this size? And if the buffer is too ...
user940969's user avatar
2 votes
0 answers
145 views

Is perfectly uninterrupted alsa sound over USB possible?

I am playing a sine wave from a Rpi3 via pure userspace ALSA to the hw device of a USB sound card (using the official PCM example, no sound servers installed). But the wave never stays perfect, after ...
Jakub Fojtik's user avatar
1 vote
0 answers
102 views

Script won't continue after command line

I am very new to Pi, Python, and this kind of programming, as a whole. I am building a data logger. Once completed, it will be deployed in areas with no internet connectivity. So I chose to create ...
skip671's user avatar
  • 11
3 votes
1 answer
159 views

Execution interruption while holding a kernel spin lock

I want to toggle an GPIO pin with a certain accuracy. (i.e. latency about 1 us). I have a Raspberry Pi 3 model. Therefore I wrote a simple test kernel module. The toggling loop does basically this: ...
Rainer Urian's user avatar
0 votes
0 answers
380 views

Raspberry Pi3 should I use multi-threading, interrupts or callbacks?

Project Description I am interfacing industrial PLC's with the Raspberry Pi 3 in order to read the efficiency of the given line, and display live results. In essence I need to do the following things:...
rrz0's user avatar
  • 123
1 vote
0 answers
162 views

Display Real-time processed images in Raspberry Pi

I am working on real time image processing in raspberry Pi. Goal is to fetch and process 64x64 frame with 60 fps. I am using numpy to process these frames. And i want to display these processed images ...
Kushal Madane's user avatar
2 votes
2 answers
1k views

How to synchronize images from two raspberry pis

I have 2 Pi Zero Ws (wifi), each with a Pi camera connected to them. Both Pis/cams are running on battery power and deployed in the desert. There is no network or internet connection. The cams are ...
ThatsRightJack's user avatar
3 votes
1 answer
4k views

HIgh resolution timer?

Is any high resolution timer available on a Raspberry Pi that can be used by an application (for micro-benchmarking, etc.) without having to write a kernel driver? The resolution I'm looking for is ...
hotpaw2's user avatar
  • 271
1 vote
2 answers
10k views

Continuesly monitor GPIO input change/events in Bash

On a Raspberry Pi you can set the GPIO pins as an output or an input. An output or an input can be either high or low. For example, to monitor the input state (high or low) of GPIO pin 26 you can ...
CousinCocaine's user avatar
-1 votes
1 answer
868 views

is rpi suitable for hard real time ECG signal processing? [closed]

I am working on moniroting system for medicacl care and I can't deside what to use , having that the processing includes denoising , segmentation feature extraction and machine learning another ...
Abyr's user avatar
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1 vote
1 answer
2k views

Trying to apply real time patch to kernel 4.9.76

Raspberry Pi 3 model B OS: Raspbian 9.3 stretch Kernel: armv7l Linux 4.9.76-v7+ CPU: ARMv7 rev 4 (v7l) @ 1.2GHz RAM: 1GB I'm trying to apply the real-time patch (it's highly desirable for my ...
shmink's user avatar
  • 137
3 votes
2 answers
185 views

CPU speed changes by a multiply of 2 for short durations

I'm using a raspberry pi and I need really fast performance from my CPU for a certain process. To achieve that, I added isolcpus=3 to my kernel boot parameters, to isolate the core for this process ...
user78252's user avatar
2 votes
0 answers
444 views

Using Hardware pwm as event timer?

in modern PC based Linux Machines it is possible to use hpet and realtime processes to get a reasonable good realtime performance (+-10us response time) While Raspberry Pi Hardware does not have a ...
Sven Geggus's user avatar
1 vote
0 answers
4k views

How to achieve better Jitter for LinuxCNC on Raspberry PI?

Question Is it possible to achieve reasonable real-time with RaspberryPi (ideally jitter < 50us, or in the worse case 150us ) If yes, how to achieve those values, targeting LinuxCNC? After all the ...
Adrian Maire's user avatar
6 votes
1 answer
13k views

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 ...
code_slack's user avatar
1 vote
1 answer
2k views

Fastest wired data transfer protocol between RPi and Android Device

I'm looking to download images that i'm capturing on RPi to my Android Device using USB, or some wired interface that I don't know about. I'm trying to avoid using wifi, ethernet, or bluetooth. I've ...
pudgy's user avatar
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2 votes
0 answers
2k views

raspi+ADC realtime plotting

I recently succeeded in receiving ADC Data from ADS7851 through SPI communication. Now I'm working on plotting those voltage data and also fft of them. I've done some research, and found out that ...
J.Daniel's user avatar
0 votes
1 answer
2k views

code to read live mic input audio frequency

My project is to create a kit to play recorded (music chords) audio file automatically changed with respect to frequency of live microphone input with a certain period.This will help the solo singers ...
dani's user avatar
  • 1
1 vote
0 answers
206 views

Setting maximum process pause time - need to read spi data with less time gaps

I am using a raspberry pi to grab data through a SPI port. Attached to the SPI port is a PIC, programmed so that it samples on an A/D at 12.8kHz, and stores the samples in a 256 long buffer. (to cope ...
J Rodgers's user avatar