• Raspberry Pi

      Raspberry Pi

      The Raspberry Pi is the most popular ARM Linux hobbyist board. There are plenty of how-to and tutorials on the web. However, not a lot like in this blog. I try to find new limits and functionalities of the board and make projects that includes home-automation, industrial data acquisition, and more.

    • Raspberry Pi
      9 min | 10056

      #Raspberry Pi 4: booting from an SSD with enabled TRIM

      Raspberry Pi | 9 min | 10056


      There are already many tutorials that explain how to boot the Raspberry Pi 4 from an SSD disk without any MicroSD card. This is just another one; but, it includes some tips that I founded on Google, because the other tutorials didn't work, nor did they explain the details.

      Let's start with some technical details. The Raspberry Pi 4 has an SPI-attached EEPROM, which contains code to boot up the system and more. The firmware of this EEPROM can be updated to include more functionalitie...

    • Raspberry Pi
      3 min | 38990

      #Raspberry Pi 4: Hardware accelerated video decoding (GPU) in Chromium

      Raspberry Pi | 3 min | 38990


      Two months ago, I wrote a tutorial that explains how to get DRM support on Chromium on the Raspberry Pi. If you follow the steps of that tutorial:

      you can use the Chromium web browser to play videos from Netflix, Hulu, HBO, Disney+, Amazon Prime, Spotify, Pandora, and many others (see Fig. 1 & 2).

      Supported Browser
      Fig. 1: Playing videos on Amazon Prime
      using Chromium on the Raspberry Pi OS.
      Supported Browser
      Fig. 2: Playing music on Spoti...

  • Product Reviews, Raspberry Pi
    3 min | 791

    #CrowPi2: a Raspberry Pi Notebook for Extended Creativity

    Product Reviews, Raspberry Pi | 3 min | 791


    Last year, Elecrow sent me the CrowPi and I used it in some of my projects, including this video:

    Together with the Corel USB accelerator, I programmed a YOLOv2 object detector, etc.

    The CrowPi kit is magnificent and has everything you need to start playing with the Raspberry Pi. Furthermore, you get everything in a suitcase, that you can close and clean your "mess" in seconds. :)

    Today, Elecrow is announcing a Kickstarter campaign to support the Crowpi2. This time, they integrated the Raspberry Pi in a notebook-like case (see fig. 1), and I think it i...

  • Raspberry Pi
    2 min | 13665

    #Raspberry Pi: Amazon Prime, Netflix, etc. and a DRM solution!

    Raspberry Pi | 2 min | 13665


    It is a rainy day and you have a Raspberry Pi, which is running Raspberry OS (Raspbian), and you think: I can make a media center to watch some movies/series. You configure everything, and then you see something like the next picture, every time that you want to watch Amazon Prime, Netflix, etc. using the Chromium Web Browser:

    Fig. 1: Trying to play Amazon Prime videos on the Raspberry Pi running Raspberry OS.

    You could install Kodi, LibreElec or OSMC, and you'll be able to watch your series or movie without any problem (using some plugins). But, if you still want to use Raspberr...

  • Home Automation, Raspberry Pi
    2 min | 935

    #CC2531 & Raspberry Pi: Philips HUE bridge v1 replacement

    Home Automation, Raspberry Pi | 2 min | 935


    As you may know, the Philips Hue Bridge v1 has support until April 30, 2020. This means, after April 30, 2020, no software updates will be made available and it will not connect to the online services. However, you can still control it locally via the "dedicated Philips Hue Bridge v1 app". Nevertheless, you have a device (connected to your network) that can be a "treasure" for hackers (MITM-Attacks), and the "dedicated Philips Hue Bridge v1 app" will disappear shortly! (...

  • Home Automation, Raspberry Pi
    6 min | 12599

    #Raspberry Pi: Controlling Philips HUE Lights (ZigBee & CC2531)

    Home Automation, Raspberry Pi | 6 min | 12599


    This article extends the tutorial about Hass.io and the Xiaomi Aqara Sensors that I've published months ago. That tutorial is part of the series of articles about Zigbee and the Rasbperry Pi using the CC2531 USB dongle. Here are the links:

  • Raspberry Pi, Single-board Computers
    4 min | 1747

    #Raspberry Pi: Encrypt (and save) Docker credentials

    Raspberry Pi, Single-board Computers | 4 min | 1747


    Usually, I login to different Docker registries (local, Docker Hub, etc.) with a computer running Ubuntu. I execute once docker login, then I enter the username and password, and after restarting the system, the access data is still available. That means, I write the credentials only once. But, on the Raspberry Pi, it was different until today: I needed to write the login credentials every time I booted the board.

    This article helps you to install the needed tools to save Docker login credentials on the Raspberry Pi, but not as plain text, so that the next time that you reboot the Raspberry t...

  • Raspberry Pi
    6 min | 6525

    #Raspberry Pi 4B: Sometimes it's cool to be hot -or warm, to be exact ;)-

    Raspberry Pi | 6 min | 6525


    This article is the last in a series of three articles that evaluates the performance of the Raspberry Pi 4B. This time the performance of Raspbian with standard kernel (4.19.y) will be evaluated with and without active cooling using two types of heatsinks. The other articles in the series are the following:

    1. The first article is about comparing the Raspberry Pi 4B and 3B+ performances:
    2. The second article compares the Raspberry Pi 4B runn...
  • Raspberry Pi, Real Time Systems
    7 min | 33558

    #Raspberry Pi 4B: Real-Time System using Preempt-RT (kernel 4.19.y)

    Raspberry Pi, Real Time Systems | 7 min | 33558


    The Preempt-RT patching article is one of the most visited articles in my blog. However, that article needed a small update: Raspberry Pi 4B is out there and with Raspbian Buster, a new version of kernel is available: 4.19.y.

    I also uploaded the compiled and patched kernel to lemariva/RT-Tools-RPi. You can follow all these steps and compile the kernel by yourself or you can download the files from the repository and deploy the kernel on your Raspberry Pi 4B.

    This tutorial is the second of a...

  • Raspberry Pi
    3 min | 12895

    #Raspberry Pi: Displaying images on an E-Ink screen

    Raspberry Pi | 3 min | 12895


    Last week, I published an article about the Raspberry Pi and an e-ink display:

    This time, this tutorial is about processing and displaying images on the 7.5" e-ink screen as shown in Fig. 1b.

    Waveshare® 7.5" E-ink Screen connected to a Raspberry Pi
    Fig. 1a: E-ink Screen connected to a RPi
    running ePaperWidgets
    Fig. 1b: Banggood's 13th anniversary
    original image here

    Hardware & Software

    You find here a list of hardware and software that you could use for ...

  • Raspberry Pi
    4 min | 9614

    #Raspberry Pi 4B: How much faster is the new CPU?

    Raspberry Pi | 4 min | 9614


    On July 4th, I ordered a Raspberry Pi 4B from Reichelt. On July 17th, I received the board, but it was broken, and a month later, finally I received a new board that seems to work OK :).

    The new Raspberry Pi 4B has a lot of upgrades and one of the most important ones is the RAM: You can choose between three models (1GB, 2GB and 4GB). But, another main change is the CPU and the RAM bus: they changed from a Cortex-A53 64-bit (3B+/3A+) to a Cortex-A72 64-bit, both ARMv8, and from LPDDR2 SDRAM...

  • Raspberry Pi
    7 min | 17170

    #Raspberry Pi: an E-Paper display with Widgets

    Raspberry Pi | 7 min | 17170


    E-paper or e-ink displays are becoming more common in recent days. You can find them e.g. on readers, clocks and sensors. Thus, I looked for an e-ink display for the Raspberry Pi and I found the Waveshare® 7.5" E-ink Screen.

    There are many projects with an e-ink display and the Raspberry Pi, but I first tried with an ESP32 and MicroPython. That solution didn't work (something was not working with the reset voltage - too much signal noise). So, that remains a work in progress and I wi...

  • Home Automation, Raspberry Pi
    3 min | 35963

    #Zigbee: Flashing a CC2531 dongle using a Raspberry Pi

    Home Automation, Raspberry Pi | 3 min | 35963


    Last April, I published a tutorial about connecting the Aqara sensors to a Raspberry Pi without using the Xiaomi Gateway. To make that possible, I needed a CC Debugger to flash the TI CC2531 Zigbee Dongle. This debugger was used only one time, and then the Zigbee-USB dongle worked without any problem.

    In this article, I will cover a way to flash the CC2531 without the CC Debugger. This reduces project costs (about $10 for debugger + cable adapters) and waitin...

  • Raspberry Pi
    2 min | 6179

    #Raspberry Pi 4B: Where were the quality controls?

    Raspberry Pi | 2 min | 6179


    On July 4th, I ordered a Raspberry Pi 4B. To be honest, I really didn't/don't need a new Raspberry Pi, I don't have any specific task for it, but I saw some cool stuff on the Internet, and I said: Ok, I need one! Thus, I bought the 4GB model on Reichelt. The expected delivery date was on July 10th but, I had to wait a little longer and I got it on July 17th! Everything was ok, and I got the following closed and sealed box (see Fig. 1):

    raspberry_pi_box-min.jpg
    Fig. 1: Box of the Raspberry Pi Model 4B (4GB RAM)

    But, as soon as I opened the box, my joy faded! :( With a quick visual control, I checked tha...

  • Home Automation, Product Reviews, Raspberry Pi
    2 min | 8994

    #Zigbee: Reading Xiaomi Sensors with a Raspberry Pi (no Xiaomi gateway needed!)

    Home Automation, Product Reviews, Raspberry Pi | 2 min | 8994


    I've been very busy the last weeks. I moved to a new apartment and I was living between moving boxes. Four days ago, I managed to put my desk together and now I have some time (not a lot) to write a new article.

    Last month I've received from GearBest two Aqara sensors:

    • Aqara Cube - internal motion sensors (gyro + accelerometers)
    • Aqara humidity, temperature and air pressure

    These sensors use Zigbee and I connected them to a Raspberry Pi running Raspbian OS and a dockerized version o...