Initial Configuration of the Ethernet Shield Arduino Uno

Introduction

We continue our course of the IoT and Arduino. In the previous article, found at this link, it has created an application that uses a sensor TMP36 and a display with which we were able to display the current temperature in the place where you were. The final goals of all is to view and change by phone or tablet thresholds of temperature sensors, all using the services of Azure for the IoT. But to interact with the internet, the Arduino Uno is not enough, you need to equip it with other components. What we will add is called an Ethernet shield, or a card connected to the Arduino Uno and the network via Ethernet cable and RJ45 connectors that will allow access to the Internet. We will see in the order:

These are the main features, but for more information, you can see the considerable documentation that already exists here, where we start from the hardware to the final program. The following is the image of the Ethernet Shield. How to connect Ethernet shield on the Arduino Uno To connect the Ethernet card and very simple, as you can see in the following pictures, just overlay the Arduino Uno, being careful not to bend or damage the pins. You will see that you replicate the network adapter, all links of the Arduino Uno, then inputs PWM, Analog inputs, inputs of transmission and reception, the output voltage of 5v and zero volts to power the circuits and external components and finally the reset button that will perform the reset, both of the Ethernet card that the Arduino board as in the following: Arduino Uno Ethernet Shield right and left before being assembled. The two boards after assembly. As you can see, the assembly is simple. As you have seen be careful not to damage the pins of the Ethernet card.

Configuration for Internet access

We are past the assembly stage, it's time to configure the adapter so that it can connect to the internet. First, we must connect the Arduino Uno to a power supply, or with the power supply that provides an output voltage of 5V DC and at least 2 amperes, or attaching it directly to the PC through a USB port, providing a voltage necessary for the operation of the card. We must have an Ethernet cable with an RJ45 connector, to be connected to the router that will be the gateway. Now we start the Arduino IDE and create a new sketch of code called "EthernetTest" as shown and we execute a project save. The new project EthernetTest. Now for the part of the code. The first thing to do after you create and save the file sketch is to include the necessary libraries to use the Ethernet Shield, exactly SPI.h and Ethernet.h.

Find these libraries from the menu Sketch -> Include Library -> Ethernet. You will find that more libraries will be added, but we can have a look at the two mentioned above. Adding libraries SPI and Ethernet.h on the project. Now that the necessary libraries have been added, we can start using them. First, we need to define a Media Access Control (MAC) address. It is a unique address for each device that is usually issued by the manufacturer of the network card necessary to identify the device, in our case the Ethernet Shield case if there were more than one. If you do not have this address, we can safely create one, taking care to enter the letter "x" after the first number, because it is an address in hexadecimal numbers. We will enter the MAC address below.