• 06
      Sep - 2019

      Raspberry Pi, Real Time Systems | 7 min | 5721

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

      Raspberry Pi, Real Time Systems | 7 min | 5721


      performance
      preempt-rt kernel
      raspberry pi 4b
      raspbian buster
      real time system

      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 serie of three that evaluate the performance of the Raspberry Pi 4B. This time the performance of the st...

    • 27
      Aug - 2019

      Deals, Raspberry Pi | 3 min | 8726

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

      Deals, Raspberry Pi | 3 min | 8726


      anniversary
      banggood
      deals
      e-ink display
      python
      raspberry pi

      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 this tutorial:

      E-ink Screen
      • Waveshare®
    • 25
      Aug - 2019

      Raspberry Pi | 4 min | 6164

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

      Raspberry Pi | 4 min | 6164


      benchmark
      buster
      jupyter
      n-queens problem
      performance
      raspberry pi 3 B plus
      raspberry pi 4b
      raspbian

      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 to LPDDR4 SDRAM. Thus, the CPU clock was increased to 1.5GHz (0.1GHz more) and the memory frequency to 2...

    • 21
      Aug - 2019

      Raspberry Pi | 7 min | 8184

      #Raspberry Pi: an E-Paper display with Widgets

      Raspberry Pi | 7 min | 8184


      e-ink display
      google apis
      google calendar
      raspberry pi
      raspberry pi zero
      waveshare

      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 will use this board. But now, in this tutorial, I uploaded a solution for the Raspberry Pi.

       Waveshare® 7.5" E-ink Screen connected to a Raspberry Pi
      Fig. 1: Wa...
    • 13
      Aug - 2019

      Home Automation, Raspberry Pi | 3 min | 6040

      #Zigbee: Flashing a CC2531 dongle using a Raspberry Pi

      Home Automation, Raspberry Pi | 3 min | 6040


      aqara
      aqara sensors
      door sensor
      home assistant
      mqtt
      pir
      raspberry pi
      xiaomi gateway
      xiaomi sensors
      zigbee

      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 waiting time. Usually, you wait 30 days to get a low cost version of the debugger (using the cheapest shipping option). Let's start!

      Hardware

      ...
    • 02
      Aug - 2019

      Raspberry Pi | 2 min | 4817

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

      Raspberry Pi | 2 min | 4817


      board broken
      capacitor broken
      quality control failed
      quality problems
      raspberry pi
      raspberry pi 4b
      tantalum capacitor

      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...

    • 09
      Jul - 2019

      Home Automation, Product Reviews, Raspberry Pi | 2 min | 2602

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

      Home Automation, Product Reviews, Raspberry Pi | 2 min | 2602


      aqara
      docker
      hass.io
      home assistant
      home automation
      product review
      raspberry pi 3 B plus
      xiaomi gateway
      xiaomi sensors

      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:

      1. Aqara Cube
      2. 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 of Home Assistant (DIY tutorial). This connection was made without using any Xiaomi gateway (DIY tutorial).

      Hardware and Software

      ...
    • 16
      Apr - 2019

      Raspberry Pi | 4 min | 3772

      #Edge-TPU: Hands-On with Google's Coral USB accelerator

      Raspberry Pi | 4 min | 3772


      coral
      coral usb accelerator
      docker
      edge-tpu
      google
      machine learning
      raspberry pi
      teachable machine
      tensorflow lite

      Last week, the Coral team released updates to the Coral platform to "address customer feedback and make it easier to use the products and tool-chain". The Python API has now the ability to run multiple models in parallel, using multiple Edge TPUs.

      Thus, due to the multiple changes, I updated the Docker image lemariva/raspbian-edgetpu which includes the Edge-TPU libraries for Raspberry Pi 3 B+, Jupyter Notebooks and some other interesting libraries (check the Dockerfile).

      edge-tpu-coral-usb-accelerator-dockerized-min.png
      Fig 1: Coral USB Accelerator, Jupyter and some training objects

      The base Docker image remained balenalib/ras...

    • 13
      Apr - 2019

      Home Automation, Raspberry Pi | 4 min | 6773

      #Raspberry Pi: Xiaomi Sensors & Home Assistant (Hass.io)

      Home Automation, Raspberry Pi | 4 min | 6773


      docker
      embedded
      hass.io
      home assistant
      home automation
      raspberry pi
      sensors
      xiaomi
      zigbee

      Last week, I published an article about using Xiaomi sensors without a Xiaomi Gateway. The gateway/hub can be replaced with a Raspberry Pi and a USB-ZigBee dongle. You find the instructions here: #ZigBee: Xiaomi Sensors using Raspberry Pi (without Gateway!).

      As you can read in that article, two repositories are available to connect and process the data from the Xiaomi sensors. Additionally, Zigbee2mqtt can be connected to Hass.io. Well, I didn't want to use HassOS (the OS on which hass.io runs), but I wanted to use Hass.io running on Raspbian, otherwise with Home Assistant running as an appli...

    • 06
      Apr - 2019

      Home Automation, Raspberry Pi | 6 min | 28110

      #Zigbee: Xiaomi Sensors using Raspberry Pi (without Gateway!)

      Home Automation, Raspberry Pi | 6 min | 28110


      aqara
      door sensor
      home assistant
      home automation
      mqtt
      pir
      raspberry pi
      xiaomi gateway
      xiaomi sensors
      zigbee

      This tutorial allows you to connect Xiaomi (or Aqara) sensors (e.g. door, pir, temperature, water, switch) to a Raspberry Pi or similar system without using any Xiaomi Gateway.

      This is what I will try to accomplish in this tutorial:

      1. Flash the USB-Zigbee Dongle with the correct FW
      2. Install a broker to connect to the sensors
      3. Configure the sensors using the broker

      Hardware

      Xiaomi sensors use Zigbee for the connection which means we need some extra components to connect to them. This is the list of needed hardware:

      Wireless Zigbee CC2531 x1
      SmartRF04EB (**) x1
      Debugger Ca...