Tag: raspberry pi
#Raspberry Pi: Real Time System - Preempt-RT Patching Tutorial for Kernel 4.14.y
Real Time Systems | 8 min | 61987
The Preempt-RT tutorial article is the most visited post on my blog. Therefore, I decided to update the tutorial to make it cleaner, and to introduce some other possible modifications and tips for solving problems.
Preempt-RT is a popular patch for the Linux kernel to transform Linux into such a real-time operating system. There is another option to get this done, and that's Xenomai (tutorial and performance tests here).
Tiejun Chen, the main responsible for the official Raspberry-Pi-RT branch, has published a video about Preempt-RT here. It includes tips, results and tests.
Getting the Sour...
This article extends the node tree of ProjectDiva to include an Arduino Pro Mini.
This article explains how to connect a Arduino Pro Mini to the nRF24Things application (Android Things). The code allows sending and receiving messages between the nodes. It uses the well-known nRF24 libraries to create a sensor mesh, where the node 0 (in this case a Raspberry Pi running the Android Things application) actuates as a "DHCP" server and assigns the node addresses in the mesh.
Preview
Requireme...
Unboxing Google AIY Vision Kit picked up at Target Manhattan Herald Square -New York!- (Target.com) . Also for the fans of Google AIY Voice Kit keep watching! If anyone made the same experience, please advise!
@Target: It will be great to hear from you!
@Google: Congratulations on your choice of business partner!If you are going to buy something in this shop, please double check the package and the contain before you leave the shop!
Update 9.07.2018: I managed to get the money back after a 45-minute chat session. Docker is a technology that emerged for about 5 years and since then it has simplified the packaging, distribution, installation and execution of (complex) applications. Usually applications consist of many components that need to be installed and configured. Installing all needed dependencies and configuring them correctly is usually time consuming and frustrating for users, developers and administrators. Here is where Docker comes to simplify this process allowing developers and users to package these applications into containers.
A container image is lightweight, stand-alone, executable pa...
After the Hannover Fair 2018, I have this weekend some time and I decided to update the #ProjectDIVA to the last version of Android Things. Today the actual version is 0.8.1 DP and the Android Things Setup Utility has the version number 1.0.19.
I have two applications running on Android Things:
- nRF24Things - Related post: here
- SensorTag-Things - Related post: here
In Oct. 2017, I wrote a tutorial for Android Things, but I checked that the tutorial needed an update, and the repositories too. That's why I'm writing this post.
What is Android Things?
This section does not change too much fr...
#Raspberry Pi: The N-queens Problem (benchmark) Preempt-RT vs. Standard Kernel
Real Time Systems | 5 min | 14101
N-Queens Problem: A Benchmarking Solver for Raspberry Pi
The N-Queens Problem/Puzzle is a well-known problem that consists of placing N chess queens on an N × N chessboard so that no two queens attack each other. For example, one possible solution to the N-queens problem for N = 4 is the following:
Fig. 1: N-queens problem example (N = 4).
Source: Google Optimization ToolsAs you can see, there aren't two queens on the same row, column or diagonal. Usually t...
The forked rpi-4.14.y-rt repo by TiejunChina is now a branch under the official Raspberry Pi repo. That means you need to type the following to clone the Preempt-RT patched Kernel
~/rpi-kernel$ git clone https://github.com/raspberrypi/linux.git ~/rpi-kernel$ cd linux ~/rpi-kernel/linux/ git checkout rpi-4.14.y-rt
Then, you can follow the tutorial from here.
The last week I was working on a real-time application (with a 1 ms sample time) that runs on an ARMv8 Cortex-A53 (Raspberry Pi 3 Model B based board) and I was wondering the differences between latencies on the standard and the Real-Time (RT) Linux kernel. I had some problems with the standard kernel version, then I thought I could analyze the latencies of both kernels, and make some conclusions. Many test are available but with older kernel versions. The tests were perfo...
You can still read this article, but a new tutorial is available here: There are a lot of tutorials for Raspberry Pi kernel patching using Preempt-RT, but I needed about 15 hours to get it working! I hate Kernel patching! and I have to say, that's not my first time. I have a system working with Ubuntu, RTAI and an Ethercat master. I patched the system more than once. But it is/was always a new thing! and It costs a lot of tim...
I will be testing the new release on this weekend!
The release notes seem promising!
I have also some new things with Docker and Raspberry Pi!
This article is outdated! I wrote the following new articles:
- #ProjectDIVA: Android Things 0.8.1 getting started!
- #ProjectDIVA: Android Things v1.0!Stay tuned!
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