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...

The new Huami's Amazfit GTR has not only inspired me but also you. Now it has just been introduced, but can now be ordered in the China shops. You get a very good price for $137.99 at Banggood for the bigger 47 mm version in the International Version. This supports English and Chinese language. The price is valid for the 47mm variation (42mm variants are currently not available) and will be adjusted as soon as you put the watch into the shopping cart (see figure at the end).

Get the Amazfit GTR now! (Discount Code: BG11GTR)

	Huami's Amazfit GTR 42 mm	Huami's Amazfit GTR 47 mm

One of the most coveted fitness trackers of 2019 is the new Xiaomi Mi Band 4. Unfortunately, due to its limited availability, Xiaomi does not directly sell the Mi Band 4 in Europe or North America, but it can now be ordered in the China shops. You can get a very good price for:

• $24.79 (+shipping costs ca. $2.30) - Xiaomi Mi Band 4 "International" Version (Discount code: BG26MI4)

Are the Xiaomi Mi Band 4 Chinese Version and NFC version suitable for non-Chinese speaking users?

Yes, they are!... Check these videos here!. You can change the language!

The device features a 0.95 inch AMOLED col...

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:

DISCOUNT CODES

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!

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:
   • Raspberry Pi 4B: How much faster is the new CPU?.
2. The second article compares the Raspberry Pi 4B running standard and Preempt-RT kernels.
   • Raspberry Pi 4B: Real-Time System using Preempt-RT (kernel 4.19.y)
   ...

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 ...

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 ...

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...

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...

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...

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 many other countrie...

The last days, I was looking for an online project management tool with bug tracking system. The best platform that I know is Jira from Atlassian. Jira offers a bug tracking and agile project management, however, it costs between $8.33 and $10 (annual/monthly payment) for the standard version with under 10 accounts. We use Jira in Finealyze and I am very happy with it, but I was looking for a free alternative for myself. Then, I found OpenProject, which describes itself as "the leading open source project management software".

OpenProject is offered in three different ways: Community, Cloud an...

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

• #Raspberry Pi: an E-Paper display with Widgets (see Fig. 1a).

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

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:

Waveshare® ...

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...

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.

Fig. 1: Wa...