Le bûcheron numérique.

capacitive sensor

Since I received my WS2812b led strip I want to use for the shelf, I didn’t stop to play with it.

But when Madame saw the rgb led strip I was testing, priorities changed.

– Let’s use it in the kitchen! And I want to be able to manually light it up.

Alright you know what it means. Let’s go working!

First try : Proximity Sensor for Arduino

I first tried to use the Proximity Sensor I bought with a Sensor Kit for Arduino. I wanted to detect the movement of a hand below the sensor.

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Imagemagick-logo Imagemagick-logo-2 Imagemagick-logo-3

Let’s imagine, for example, that you own a blog and you sometimes write a blog post.

You may need to resize your images or create images thumbnails in batch.

ImageMagick is a program/lib that can create, edit, compose, or convert bitmap images. It provides many usefull scripts that can help you.

Mogrify is one of them. It provide an easy way to processing your images.

Let’s make some thumbsnails:

Once you have all your images in your directory create a thumbs subdirectory:

> ll
total 8,4M
-rw-rw-r-- 1 matthieu matthieu 4,1M avril 30 16:14 led-off.jpg
-rw-rw-r-- 1 matthieu matthieu 4,0M avril 30 16:14 led-on.jpg
-rw-rw-r-- 1 matthieu matthieu 443K avril 30 16:14 ledstrip.jpg

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iot4i first release!
30 April 2017


Last week I told you about my new project, the scotchshelf, a rgb wooden shelf.

I worked on the digital part of the project, and the iot4i project is born!

You can find two projects in the iot4i group on gitlab:

The first milestone had only one business feature : we wanted to set the current color from a web browser, and see that the led strip bright with this color.

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IOT devices inception
25 April 2017


Let’s talk about IOT.

In this post I said I wanted to learn how to use Arduino compatible micro-controllers.

Do you remember the dream layers of the movie Inception? What I discovered is almost as disturbing. There are a ton of available chips, and each chip can be integrated in a ton of module boards, and those module boards can be integrated on other development modules

So to make it clear in my mind, I proceeded by choosing the chip first, then the module, and finally I found what I wanted with a development board.

And that is my feedback.

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spring boot

Yesterday I wanted to test a REST endpoint written in SpringBoot. The particularity of this endpoint is that it return a Chunked Result.

When using SpringBoot, Http tests are really simplified with the usage of MockMvc:

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Gitlab CI and Pages
16 April 2017

Gitlab CI and Gitlab Pages allow you to deploy automatically your static assets on a Gitlab server.

This is how this blog runs :)

So each project you create on Gitlab can have its own pages, deployed depending rules you set in the Continuous Integration file, the .gitlab-ci.yml.

What you can do with Gitlab pages and gitlab-ci:

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The first project I want to share with you is a D.I.Y. wood shelf that contains RGB leds, controlled with either a microcontroller like ESP8266 FR or a Raspberry Pi Zero W from a web control center. Many good Scotch bottles will stand proudly on this creation! The control center: runs on raspberry pi responsive reactive allows me to add an iot item on demand The shelf: can be powered ON and OFF with an interuptor. ... Read More


Back in the club with a quick little feedback on HUGO that is the static website engine that runs this blog.

I started to work on HUGO yesterday, so I can only tell you what I feel after few hours.

Let’s go back few month ago when I had a try with Jekyll for the recalbox.com blog, an other static website engine written in Ruby, but I was not convinced. The thing was too low to compile, and too complex to run, even with Docker. I made a quick homemade blog engine for recalbox.

I think @LionelDulout talked to me about HUGO two months ago, and I told myself I would give it a try for recalbox. But I needed to make my own blog, so here it is :)

So what do I like so far with HUGO :

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15 April 2017

Welcome everyone.

I decided to make this blog to share with anyone who would be interested feedback on :

  • what I do for living : Software Enginner in Scala/Java and everything.
  • what I do for fun : recalbox and D.I.Y. things.

You can follow me here, on twitter/digitalumberjak, on github/digitallumberjack and on gitlab.com/digitallumberjack

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