Posts


  • USB Powersupply ( lang: en )

    More and more devices are powered with an USB plug. They require more and more power but some USB sockets are designed to deliver 500mA or 1A max. It would be danregous to plug such devices to USB HUBs or to computers. I am tired of looking for a matching power supply and to have tons of them. Thus I designed a very simple power supply to plug up to 5 devices, deliver up to 10A and to individually switch them. I’ll connect my light LED panels (10W) on this PSU and my phone.

  • Multiprotocol IoT infrastructure ( lang: en )

    I made my first home automation system 6 years ago, in 2014 and had little choices in terms of hardware and software. Now, things changed and I can redesign it to better suit my needs with about 100 connected sensors and actuators, domoticz as the user interface, MQTT to centralize MySensors and Zwave meshed network events, NodeRED as an MQTT ETL, Redis Streams, Redis Timeseries and Redis PubSub as a storage… Everything on a Raspberry Pi 3. Lets have a look at the prototype.

  • FC007 - Linear bench power supply ( lang: en fr )

    Here is the design, build and test of a simple fanless 30V-3A(100VA) linear bench power supply, based on one LM723, two 2N3055, a chinese multi-meter module and two galvanometers. It will have voltage regulation 0-30V and current limiting 0-3A.

  • Redis 06 - Data scalability and distribution ( lang: en fr )

    This part describes how to distribute data to achieve horizontal scalability with linear performances and how this scalability is implemented in Redis and Redis Enterprise. The query execution distribution will be explained in the next part.

  • FC006 - iRobot Roomba Virtual Wall ( lang: en fr )

    iRobot sells autonomous Vacuum cleaners Roomba. They have IR receiver to detect obstacles and to receive remote control commands. iRobot sells a “virtual wall” 40€ to create a border in order to constraint the robot in a part of the room to clean. Hardware parts cost les than 10€ ! I decided to create my own, based on ATtiny AVR microcontroller.

  • Redis 05 - NoSQL Origins, goals and challenges ( lang: en fr )

    This part will describe some general concepts and challenges in NoSQL : Scalability, High-Availability, Consistency and Performances. It is needed to make the next parts easier to understand.

  • Redis 04 - Redis modules introduction ( lang: en fr )

    I already listed the native Redis data-structures. Redis can dynamically load modules to implement any data-structure or any feature inside its core, leveraging its architecture. Now, I try to give an overview of this infinite extensibility.

  • Redis 03b - Native datastructures (part 2) ( lang: en fr )

    I’ll give a short overview of Redis native datastructures, what can they be used for, what can be stored inside, how to use it. In the previous part, I described the basic native datastructures.

  • Redis 03a - Native datastructures (part 1) ( lang: en fr )

    In this first part, I give a short overview of the most commonly used Redis native datastructures, what can they be used for, what can be stored inside, how to use it. In the next parts, I’ll describe the remaining native datastructures.

  • Redis 02 - a key-structure store ( lang: en fr )

    In this content, I explain the differences between relational schema, a key-value schema and a key-datastructure schema.

  • Redis 01 - Introduction ( lang: en fr )

    I try to present an overview of Redis, its history, what it can do, how it works, in a very short introduction. I present briefly the performances, the optimizations, the savings.

  • RedisLabs Enterprise Cluster Nodes IP management ( lang: en fr )

    RedisLabs Enterprise Cluster (RLEC1) nodes can split network traffic in two categories: internal using one and only one network interface to communicate between nodes for replication and cluster management, and external using one or more interfaces for application connections. Here is how to change these settings after initial setup, using the REST API or the commandline tools.

    1. RLEC, RedisLabs Enterprise Cluster, is now known as Redis^e for Redis Enterprise. 

  • 3D printed wrapping wire dispenser ( lang: en fr )

    I often use wrapping wire for my electronic projects. Either I wrap the wires for quick prototyping, and then I can unwrap them, or I solder them when I want a more long term prototype. Banggood sells 8 colors of wrapping wire in 300m spools, at 8€ each. I bought one of each and needed a convenient storage and dispenser.

  • Iot sensor on ESP8266 sending values to Redis ( lang: en fr )

    Create a light sensor using an ESP8266 and an LDR for 5€, directly send the measures to a Redis database via a Wifi/TCP/IP stack and publish a push notification to notify your frontend user interface (described in a future blog post) that there is a new value to display in realtime. Redis is an in-memory key-value store with persistency to disk, high-availability and clustering. It is so easy to use that a simple micro-controller, such as an Arduino or an ESP8266, with a TCP/IP stack can connect and use it.

  • Playing with Redis and Geo queries ( lang: en fr )

    While I was searching for sample data to play with in Redis, I discovered not only a good sample dataset but also a feature to play with. The dataset contains Lat/Lon/Alt values and Redis has powerful and interesting geo operations. This post describe a way to bulk load data airports, airlines and routes with indexes into Redis^e Pack (Enterprise edition previously known as RLEC) and how to query by distance.

  • Drone safe arming with Taranis (OpenTX) ( lang: en )

    Zero throttle and yaw right is the standard for arming a drone. It is fine, but I wanted to add security with a switch, without wasting an extra channel or introducing a security breach. The idea is to add an easy but improbable step to arm the drone, to change nothing to disarm the drone, and to not add a security issue during flight. When I was young(er), I was told that security needs to ne non-invasive to be efficient… This is my solution, maybe not the best one, but better in my opinion to all that I found on the net.

  • How to configure Amazon's Route53 DNS for RedisLabs Enterprise Cluster ( lang: en fr )

    RedisLabs Enterprise Cluster (RLEC1) needs a proper DNS configuration to achieve high-availability (HA) and fail-over. This post describe how to configure Amazon Web Services’ (AWS) Route53 DNS properly.

    1. RedisLabs Enterprise Cluster 

  • Configure JDBC for Couchbase ( lang: en fr )

    Here, we will see how to download, install, configure and use Simba’s JDBC driver for Couchbase. We will test the connection with SQuirreLSQL and the driver will be configured for any other incomming connection.

  • Introduction to NoSQL reporting ( lang: en fr )

    Whatever the database technology is, there is a business application using it and there is most of the time a reporting need on the business data. I will try to introduce how to design a reporting architecture, the concepts are applicable to relational SQL databases and to non-relational NOSQL databases either. There are two distinct reporting needs : the operational reporting, which applies to live operational data to create operational reports such as invoices, order forms, assets inventories, and so on, and the business intelligence reporting which is higher level reporting to give trends and to help people to take decisions. In this first post, I’ll try to explain the reporting general concepts.

  • Create a D3 chart with CEAN and N1QL on Couchbase ( lang: en fr )

    Couchbase, has a full CEAN stack (Couchbase Express Angular NodeJS) to quickly develop NodeJS application. We will see in this tutorial how to initialize the development of a new NodeJS application using CEAN with Yeoman, create a server-side service, a controller and views for client side graphical and modern representation of data

  • Loading data in Couchbase with RxJava ( lang: en fr )

    This short tutorial explains how to find an interesting data set (quantitatively and qualitatively) and load it into Couchbase in order to play with it. This is a quick and dirty application, it could be largely improved and optimized. I wrote it quickly because I needed something quickly up-and-running to load my data. I decided to write a post on it and I only cleaned the very-dirty things before writing this post. It is clearly not a production-class program ! ;)

  • JDBC connection from JasperReports Server to Couchbase ( lang: en fr )

    Couchbase, a NOSQL BigData database, now offers a new language, N1QL, to write queries. This article will show you how to use the new Couchbase JDBC driver in JasperReports Server (I will use tje JRS acronym from now), in order to execute SQL(92) queries on the Couchbase database.

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