tutorials

Posted on by Jean-Luc Aufranc (CNXSoft) - 1 Comment on Crowbits Master Kit Tutorial – Part 2: ESP32 intrusion scanner and visual programming

Crowbits Master Kit Tutorial – Part 2: ESP32 intrusion scanner and visual programming

Crowbits Intrusion Scanner

I started Crowbits Master Kit review last month by checking out the content, user manual, and some of the possible projects for the ESP32 educational kit including a 2G phone and a portable game console. For the second part of the review, I’ll go through one of the lessons in detail, namely the intrusion scanner to show the whole process and how well (or not) it works. Let’s go to Lesson 5 directly, although I’d recommend going through the first lessons that provide details about the hardware and visual programming basics using Letscode program, which is basically a custom version of Scratch for Crowbits The user manual introduces the project, explains it is to detect intruders, and lists the learning goals as we’ll learn how to control the servo and play music on the Crowbits kit. Kit Assembly But first, we’ll have some assembly to do, in a similar way […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 6 Comments on Encoding and decoding AVIF pictures with open-source software & libraries

Encoding and decoding AVIF pictures with open-source software & libraries

avif vs png

One of the new features of Android 12 is support for the AVIF file format that provides much smaller files at the same level of quality. Jake Archibald has done a great job comparing AVIF format to JPEG, WebP, and other still picture formats, and the results are really impressive. Besides Android 12, AVIF is already supported in Chrome browser, will be enabled by default in Firefox 86, but here’s we’ll look at some of the open-source programs and libraries that allow you to manipulate AVIF pictures. With libavif library, AOMedia has published a reference implementation in C, together with avifenc and avifdec tools, that rely on various codecs, but it appears rav1e is recommended for encoding AVIF picture, while dav1d is the best choice for AVIF decoding. libavif will not automatically build the codec, and they need to be enabled in CMakeLists.txt

as well as define the path […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 1 Comment on Maker Pi Pico STEM board mini review with CircuitPython

Maker Pi Pico STEM board mini review with CircuitPython

Maker Pi Pico First Boot

In my early list of third-party Raspberry Pi RP2040 boards, I shortly mentioned Cytron Maker Pi Pico baseboard for Raspberry Pi Pico that exposes all pins via female headers, includes LEDs for all GPIOs pin, six Grove connectors, three user push-buttons, one RGB LED, a piezo buzzer, an audio jack, a MicroSD card, and an ESP-01 socket to add WiFi connectivity. The beta version sold for $5, and at the time I missed that included Raspberry Pi Pico board as well, so basically you got a free baseboard. The Malaysian company has now sent me a review sample to play around with, so let’s have a closer at the hardware and code samples for the board. Maker Pi Pico Unboxing and Specifications I received the board in Cytron package together with a pinout diagram for Raspberry Pi Pico, and we can see the latter is already soldered to Maker Pi […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 45 Comments on Getting Started with Raspberry Pi Pico using MicroPython and C

Getting Started with Raspberry Pi Pico using MicroPython and C

Raspberry Pi Pico Blink LED

Raspberry Pi Pico board was just launched last Thursday, but thanks to Cytron I received a sample a few hours after the announcement, and I’ve now had time to play with the board using MicroPython and C programming language. I went to the official documentation to get started, but I had to look around to achieve what I wanted to do, namely blinking some LEDs, so I’ll document my experience with my own getting started guide for Raspberry Pi Pico using a computer running Ubuntu 20.04 operating system. The instructions will be similar for Windows and Mac OS. Preparing the hardware In theory, we could just get started with the board alone, but since I got some headers with my board, I also took the opportunity to try out Pine64 Pinecil soldering iron powered by MINIX NEO P2 USB-C power supply. The soldering iron worked great for about one minute, […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 4 Comments on Reading Vehicle OBD-II data through CAN within a containerized application in Embedded Linux

Reading Vehicle OBD-II data through CAN within a containerized application in Embedded Linux

telematics applications overview-GNSS CAN Cloud embedded Linux

CNXSoft: This is a guest about OBD-II and CAN support in embedded Linux by Andre Márcio de Lima Curvello, Sr. FAE and Technical Evangelist, Toradex A connected world makes it possible to track your online orders being shipped to your home through your smartphone in real-time, and getting information about your vehicle such as tire pressure, outside temperature, and even details like if a lamp is broken – has begun to be possible via smartphones in modern vehicle models. But behind the magic of knowing where the truck carrying your package is at all times and other details of the vehicle, there is a very complex world made of embedded devices ‘talking’ to each other so the information makes its way from the device to you. In this article, you will learn how to create an application to communicate with a vehicle through CAN via the OBD-II standard. We use […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 3 Comments on How to develop Gstreamer-based video conferencing apps for RDK & Linux set-top boxes

How to develop Gstreamer-based video conferencing apps for RDK & Linux set-top boxes

gstreamer zoom video conference

CNXSoft: This is a guest post by Promwad that explains the basic steps to develop a video conferencing app with Gstreamer on TV boxes running Linux. The COVID-19 pandemic has become a catalyst for new online services. For example, Zoom became so successful that it overtook IBM in terms of capitalization this month. The software engineers at Promwad were inspired by this success and decided to go even further: what about implementing video conferencing on Smart TV and STBs? Then the users of such an application will have an opportunity to communicate not only at work but also to enjoy remote meetings with friends, cheer for a soccer team, watch a movie together, or do sports with a coach. For some reason, most digital TV operators do not have such a service, although, from an engineering point of view, all these features can be implemented on set-top boxes based on […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 1 Comment on No password SSH – Login to a SSH server with private/public keys

No password SSH – Login to a SSH server with private/public keys

If you often need to establish SSH connections to a server, entering the password each time may be a hassle or even a non-starter. For example, in our case, we use ssh connections in our nightly build scripts, so obviously entering a password would not be an option here… So it can be useful to configure the server and your client to accept secure ssh connection without the need to enter a password.  What must be done, then, is to generate a public/private key pair, and copy the public part into the appropriate place on the server side. For doing this, on the user’s home directory, on the client machine, type:

-t tells the type of encryption -f tells where to store the public/private key pairs. In this case, the .ssh directory in the home directory is being used A password will be asked;  leave this part blank, just […]

Posted on by Jean-Luc Aufranc (CNXSoft) - 9 Comments on How to Take a Remote Screenshot in Raspberry Pi over SSH

How to Take a Remote Screenshot in Raspberry Pi over SSH

remote screenshot raspberry pi ssh

I recently reviewed a Raspberry Pi 4 laptop with a custom interface that made it impractical to take screenshots directly on the device. So instead I had to take screenshots remotely over SSH. It’s quite easy to do. Most of the steps can be reproduced in other Linux systems, and are not specific to Raspberry Pi. Enable SSH in Raspberry Pi First, enable SSH either with sudo raspi-config in a terminal window and selecting 5. Interface Options, then P2 SSH… If for some reason, you don’t have access to the terminal, take out the MicroSD card from the Raspberry Pi board, and from a computer create a new empty file named “ssh” in the boot partition. Now provided you have the username and password for your board, you can connect to SSH with the IP address from a terminal:

or a program like Putty. Taking a screenshot remotely You’re […]

Exit mobile version