I'm trying to connect my Arduino Uno with MySQL.

This is my code:

#include <SPI.h>
#include <Ethernet.h>
#include <sha1.h>
#include <mysql.h>

/* Setup for Ethernet Library */
byte mac_addr[] = { 0xC8, 0x0A, 0xA9, 0xAF, 0x83, 0x58 }; 
IPAddress server_addr(192,168,0,102);

/* Setup for the Connector/Arduino */
Connector my_conn; // The Connector/Arduino reference
char user[] = "root";
char password[] = "fifa2005";
char INSERT_SQL[] = "INSERT INTO test_arduino.hello VALUES ('Hello from Arduino!', NULL)";

void setup() {
if (my_conn.mysql_connect(server_addr, 3306, user, password))
Serial.println("Connection failed.");

void loop() {

I have the following database:

mysql> CREATE DATABASE test_arduino;
Query OK, 1 row affected (0.00 sec)
mysql> USE test_arduino;
Database changed
mysql> CREATE TABLE hello (source char(20), event_date timestamp);
Query OK, 0 rows affected (0.01 sec)

This is the output message:

Connecting... Connection failed.

I am not sure this is the right IP address: 192,168,0,102. I tried with the localhost IP address -, but nothing happened.

  • What kind of system is MySQL running on? E.g. Windows, Linux, MacOS? Apr 6, 2015 at 23:37
  • 1
    Is the address of the computer you're trying to connect to, or is that the address of the ethernet shield? I'm confused as to why you would try connecting to localhost...
    – Comintern
    Apr 7, 2015 at 1:31
  • My operating system is windows 7. is ip adress of my laptop. At first I thought that I need to use IP address of the server but then I saw that actually need the IP address of my laptop
    – Supreme
    Apr 7, 2015 at 6:56
  • You need to use the IP address of the server running MySQL. Apr 7, 2015 at 9:15
  • I use Apache to create a Mysql server and corresponding IP is and it doesn't work with it. Ethernet shield and laptop are connected to the router. I think the problem is mac address or ip address which i used. I take the mac address from: cmd -> ipconfig -> Ipv4 address - 192,168,0,102. I take the mac address from : cmd -> getmac -> Physical Address.
    – Supreme
    Apr 7, 2015 at 12:52

2 Answers 2


First you have to grant permission to the user!

Type the query in MySQL like:

GRANT ALL ON test_arduino.* TO root@'' IDENTIFIED BY 'fifa2005';

Can't comment, so I put here. In your Arduino you shall use unique MAC address, that can't be same as in your laptop or any other node in network segment. And it can't be just any number because some bits have different meanings, so to be safe, use MAC from Ethernet shield samples (BTW in production units, MAC addresses have to be purchased, but unfortunately Ethernet shield comes without it). is a "virtual" localhost address (alternative address used to access the services within same host), in your case you shall use MySQL server (your laptop?) host address, so

> server_addr(192,168,0,102);

is right.

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