• 16
      Jan - 2020

      11 min | 1761

      #MAixPy: Object detector - MobileNet and YOLOv2 on Sipeed MAix Dock

      MicroPython | 11 min | 1761

      machine learning
      maix dock
      object detection
      tensorflow lite

      This tutorial is about training and deploying a YOLOv2 object detector on a MAix M1w Dock Suit running MicroPython. The MobileNet is used as a pre-trained model for the training.

      Therefore, this tutorial will try to accomplish the following points:

      1. A quick introduction to YOLO(v2)
      2. A quick introduction to MAix KPU
      3. Training, evaluation, and testing of the object detector model (on Jupyter-Notebooks running on Docker)
      4. Flashing the trained model on the MAix M1w Dock Suit running MicroPython (MAixPy)
      5. Detecting a BRIO locomotive using the MAix M1w Dock Suit

      A training example is included, which is...

    • 12
      Jan - 2020

      Embedded Systems, LoRa
      1 min | 103

      #LoRaWAN: Dragino Gateway online in Hanover

      Embedded Systems, LoRa | 1 min | 103

      the things network

      This is a short article to share with you that I've just registered a LoRaWAN gateway and right now I have one of the 10106 online gateways connected (see Fig. 1) to "The Things Network"!

      I got from DigitSpace a Dragino LG02 Gateway (868MHz) and now in Hanover, you can see a gateway running in the List district.

      • LoRa 2-Channel Gateway


      Fig 1: LoRaWAN gateways in Hanover

      I will be making some tests in the coming weeks, and I am planning to redesign the ...

    • 05
      Jan - 2020

      1 min | 667

      #NewDecade2020: Celebrating 2020 with a quick look back at 2019

      General | 1 min | 667

      coral usb accelerator
      diy projects
      happy new year
      orange pi
      raspberry pi

      The following video summarizes the project highlights of 2019! Most of them are implemented using MicroPython on ESP32 and Python on Raspberry/Orange Pi.

      The flying video was recorded with a Nexus 5X mounted on the Zhiyun Smooth 4. In the video-edition process, software stabilization was only used on the vertical axis. The Zhiyun Smooth 4 smoothed the horizontal movements.


      Following components are used in the video. They are listed by order of appearance:

      Zhiyun Smooth 4
      • Zhiyu...
    • 24
      Dec - 2019

      4 min | 1046

      #M5Stack: Christmas Lights using MicroPython & WS2812B Leds

      MicroPython | 4 min | 1046

      esp32 projects
      m5stack fire
      micropython extensions
      ws2812b leds

      Holiday season has begun and Christmas and the New Year 2020 are approaching! This means, time to reflect and to clean up code and, therefore, I am updating some of the GitHub's projects to summarize the year. I started with the Christmas lights project! But, this time, I took the M5Stack Fire and a new LED panel (WS2812b - 16x16 pixel) and with the XMasLight project, these are the results (Fig. 1 & 2):

      xmas_2020-min (1).png
      Fig. 1: M5Stack and a new WS2812b Panel (16x16 pixel).

      Hardware and Software

      The following hardware and software is used in this tutorial:

    • 04
      Dec - 2019

      Home Automation, Raspberry Pi
      6 min | 6351

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

      Home Automation, Raspberry Pi | 6 min | 6351

      home assistant
      home automation
      philips hue

      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:

      Fig. 1: Hass.io: Philips HUE Lightstrip.

      In Zigbee: Xiaomi Sensors using Raspberry Pi (...), I...

    • 01
      Dec - 2019

      Analytics, Cloud Platforms
      4 min | 1063

      #Portainer: Managing Docker Engines remotely over TCP socket (TLS)

      Analytics, Cloud Platforms | 4 min | 1063

      docker engine
      docker enviroments
      docker management
      google cloud platform
      raspberry pi

      This tutorial is about managing a Docker Engine remotely using Portainer connected to the protected Docker daemon socket (TCP port 2376). By default, you can manage Docker locally through a non-networked UNIX socket (option -v /var/run/docker.sock:/var/run/docker.sock while running Portainer). But, if you want the Docker Engine to be reachable through the network in a safe manner, you need to enable TLS by specifying the --tlsverify flag and pointing Docker’s --tlscacert flag to a CA certificate. Then, the daemon only accepts connections from clients that are authenticated by a certificate si...

    • 14
      Nov - 2019

      Raspberry Pi, Single-board Computers
      4 min | 1240

      #Raspberry Pi: Encrypt (and save) Docker credentials

      Raspberry Pi, Single-board Computers | 4 min | 1240

      docker enviroments
      docker hub
      docker registry
      embedded systems
      raspberry pi

      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...

    • 10
      Nov - 2019

      1 min | 540

      #Elfter im Elften: Singles’ Day Deals (11.11 > single)

      Deals | 1 min | 540

      shopping day

      Today is Singles' Day or "Guanggun Jie" in Chinese, which is a popular shopping festival among young Chinese people, who celebrate their pride of being single! Thus, I got some discount codes from Banggood for Today and I'm publishing them here:

      This section is new in LeMaRiva|Tech and I will update it every day with new discount codes! I receive a list every day with new codes and I will use some analytics to select the best offers for you and automatically publish them there. Stay tuned!

      I cannot guarantee that all codes I published on this list work. I analyze the data (p...
    • 10
      Nov - 2019

      Raspberry Pi
      6 min | 5127

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

      Raspberry Pi | 6 min | 5127

      ice tower cooler
      n-queens problem
      raspberry pi 4b
      temperature test

      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 running standard and Preempt-RT kernels.
    • 05
      Nov - 2019

      Product Reviews
      5 min | 3425

      #Xiaomi CMSXJ11A: an IP-Camera with built-in battery

      Product Reviews | 5 min | 3425

      ip camera
      product review
      xiaomi ecosystem

      This article evaluates three low budget Wi-Fi cameras that I buy from e.g. banggood.com and aliexpress.com but I will focus most of the analysis on my last acquisition the XIAOMI Mijia CMSXJ11A.

      All cameras in this review are Xiaomi (not exactly built by Xiaomi) and can be connected to the application Mi Home (apple/android). Moreover, you need to select the region to China (Mainland) in the application, otherwise you are not going to find the devices. This has a main disadvantage: the servers are in China Mainland. The documentation is also still in Chinese, and sometimes the cameras talk to ...

    • 16
      Oct - 2019

      Product Reviews, Single-board Computers
      6 min | 10546

      #Orange Pi Zero LTS: An 'upgraded' alternative to the old Raspberry Pis

      Product Reviews, Single-board Computers | 6 min | 10546

      armbian buster
      development boards
      n-queens problem
      raspberry pi

      The Allwinner H2+, which integrates four ARM-Cortex A7 cores that can clock up to 1.2GHz, is powering the Orange Pi Zero LTS. The tiny board, which measures just 52 x 46 mm, features 802.11 b/g/n Wi-Fi, Ethernet, up to 512 MB of RAM, USB 2.0 Type-A and a microSD card slot. There is also a 26-pin unpopulated GPIO header along with a 13-pin header for a headphone, USB 2.0, TV-out, microphone and IR signals.

      This board is the next generation of the Orange Pi Zero that was first launched in November 2016 for $7 and up. It should solve various issues with the Allwinner XR819 WiFi module that many ...

    • 23
      Sep - 2019

      Product Reviews, Single-board Computers
      6 min | 5164

      #Rock Pi S: a tinier version of the Raspberry Pi with Alexa functionalities

      Product Reviews, Single-board Computers | 6 min | 5164

      Alexa functionalities
      debian stretch
      development boards
      OS image
      Rock Pi S

      Radxy, the company behind the Rock Pi 4 is back! A couple of days ago, I've received the Rock Pi S (see Fig. 1), a miniature developer board that measures just 38 x 38 mm. The board is powered by the Rockchip RK3308 SoC, which integrates four 64-bit ARM Cortex-A35 cores (Ultra-High-Efficiency). Each of the cores reaches up to 1.3 GHz. The SoC also has a built-in voice activity detector (VAD) for use with IoT and smart voice applications.

      Despite its tiny size, the Rock Pi S includes a 26-pin GPIO header along with a 26-pin audio/voice header and a microSD card reader. Additionally, the Rock P...

    • 15
      Sep - 2019

      6 min | 7661

      #MicroPython: Taking photos with an ESP32

      MicroPython | 6 min | 7661

      esp32 projects
      micropython extensions

      Last year, I bought an ESP32-CAM board from Banggood and I wanted to use it with MicroPython. The board has an OV2640 without any chip (buffer) between the ESP32 and the camera. There are many implementation for Arduino or directly using Espressif, but I wanted to use MicroPython. Thus, the only solution was to use the I2S interface, but I didn't have time to write the driver. Thus, I put the project on hold. However, last week I was searching between the ESP32 boards that I have, I found the board again, and I also found that tsaarni has written the driver for MicroPython.

      This tutorial is a...

    • 06
      Sep - 2019

      Raspberry Pi, Real Time Systems
      7 min | 13670

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

      Raspberry Pi, Real Time Systems | 7 min | 13670

      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 series of three that evaluate the performance of the Raspberry Pi 4B. This time the performance of the s...

    • 04
      Sep - 2019

      3 min | 1353

      #Banggood 13th Anniversary: be ready for the BIG Sales!

      Deals | 3 min | 1353

      e-ink display

      Banggood is celebrating its 13th anniversary by launching a grand sales that takes place between the dates August 27th and September 18th (my birthday! :)).

      Fig. 1: Banggood's 13th anniversary image on an E-ink screen (tutorial)

      Banggood, founded in 2006 and located in Guangzhou, is the fourth largest international e-commerce retailer in China. By running its website www.banggood.com and smartphone applications, Banggood sells more than 500,000 types of products to the United States, Great Britain, Germany, France, Spain, Italy, Australia, Russia, Japan and ma...