WiFi Temperature Sensor with NodeMCU/ESP8266

With all the buzz around ESP8266 chips, I decided it was time to give it a go. If you are not familiar with ESP8266 chips, they are basically damn cheap (~ 3 €) WiFi chips that can also run your Arduino code. I bought on eBay a NodeMCU and had it up and running in Arduino IDE in no time. The project I’m talking about below is a DS18B20 sensor sending temperature data to a MQTT topic so that my home automation system (Jeedom with the MQTT plugin) can display it. »

Introducing Grapi: Generated REST API

I’m pleased to officially announce Grapi today. Grapi (Generated REST API) is a Java source code generator based on APT (Javac plugin). As explained on GitHub page, Grapi analyzes your JAX-RS source code and generate some code in order to expose your JAX-RS resources through Netty. »

How to connect Adafruit NFC Shield to a Mac, via libnfc

Intro I’ve recently been experimenting with NFC projects. The first test was done using an Adafruit NFC Shield for Arduino. I was able to get my code working with the default setup (that is using the shield with an Arduino). However, as I need to test Peer-to-Peer mode (P2P for short) in NFC, I quickly found out that this is not something easy to do with an Arduino. While the PN532 chip on the shield do have such capability, the Arduino libraries are far from being mature and don’t support this, yet :-( So, I decided, I should first try out libnfc and if it works, I could replace my Arduino with a Raspberry Pi. »

Arduino, BeagleBone and XBees - Oh My!

Sorry, I couldn’t find a better blog post title :-( This blog post is actually something like a mix of my two previous blog posts. I’ve enhanced the previous RGB Led Strip project controlled by an Arduino in order to send temperature readings via XBee to another XBee node. The reason why I want to do this is that I want to control some RGB Led Strips in my home with various intelligent modes (like the example one based on temperature). But as I need some sensors for this intelligence, I thought this was an interesting opportunity for building some Home Automation right there and gather sensors data from those lighting nodes to a gateway one which would keep all the data in a central place and provide a way to interact with all the various nodes. »

RGB Led Strip controlled by an Arduino

I bought a few weeks ago some quite cheap 5 meters RGB LED strips (60 LEDs per meter) on eBay. My intent is to drive them with a custom Arduino receiving commands over some XBees. I was in need of MOSFETs in order to drive the 3 RGB channels, and again found some cheap ones on eBay I received a few days ago. Today was a good opportunity for doing some basic tests. My first step was to control the color of the RGB LED Strip with the help of the MOSFETs and an Arduino. Before your read the rest of this blog post, you should read Adafruit tutorial on RGB LED Strips and Bildr tutorial on MOSFETs. I mostly did what Adafruit tutorial explains, except I added 10kΩ resistors, between each control/gate pins and ground (so 3 resistors for a RGB strip), in order to force the signal to LOW until the Arduino kicks in! »

BeagleBone: Serial Ports and XBees

I bought a few months ago a BeagleBone. I wanted to experiment using it those last days in order to get some XBee data from my previous Stalker project. Having a bit of experience with Arduino and Stalker did not help much. The BeagleBone is a complete embedded Linux system and you can’t expect to use it as easily as an Arduino (although the NodeJS demo is really cool – programming via the web browser instead of uploading programs). Simple things like using the UART (the BeagleBone has 6 UARTs, but only 4 of them available for your programs) did turn out to be a PITA. Hopefully I could find some interesting blog posts explaining how to set them up. So in this blog post, I will try to explain how to set up properly UART1 and UART2, and then how to connect an XBee to UART2 (there is way more information available on the Internet on how to use UART1, hence my choice to illustrate UART2 usage) in order to receive the data sent by my Stalker. »

A few Stalker v2.1 glitches that can easily be solved

I finally received my order at SeeedStudio last Wednesday. It came nicely packaged and until yesterday, I had not a chance to test the Stalker. After a few hours playing with it, I must say that this is a really cool Arduino board from which you can do plenty of stuff. I went through the tutorial for the Stalker v2.1 on the Wiki and experienced a few glitches for which I found solutions that might help some of you :-) The problems I had where mostly related to: compatibility with Arduino 1.0 interrupts »