Arduino - control LED via wifi based on mysql database value [closed] - mysql

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I have:
home server setup with MySQL database and available to network
Arduino with WiFi shield connected to LEDs
Both above are working hunky dory - the Arduino connects to the WiFi and is assigned an IP address.
What I'm now trying to do is write some Arduino code that would read the value stored in the web server database.
If I can work out how to do that, I could take it from there. Could someone provide an example of how to do so?
Extra detail on what I've done so far:
Below code connects to wifi using wifi shield.
Am using Arduino Uno and v 1.05 of IDE
PHP/MYSQL set up on local NAS - ip 192.168.0.102/web/homeserver
So in short, just need to know what's required to query a web server/db from an arduino already connected to the Network.
#include <WiFi.h>
char ssid[] = "SSID_IS_HERE"; // your network SSID (name)
char pass[] = "MY_PASSWORD"; // your network password
int status = WL_IDLE_STATUS; // the Wifi radio's status
void setup() {
// Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
// don't continue:
while(true);
}
// attempt to connect to Wifi network:
while ( status != WL_CONNECTED) {
Serial.print("Attempting to connect to WPA SSID: ");
Serial.println(ssid);
// Connect to WPA/WPA2 network:
status = WiFi.begin(ssid, pass);
// wait 10 seconds for connection:
delay(10000);
}
// you're connected now, so print out the data:
Serial.print("You're connected to the network");
printCurrentNet();
printWifiData();
}
void loop() {
// check the network connection once every 10 seconds:
delay(10000);
printCurrentNet();
}
void printWifiData() {
// print your WiFi shield's IP address:
IPAddress ip = WiFi.localIP();
Serial.print("IP Address: ");
Serial.println(ip);
Serial.println(ip);
// print your MAC address:
byte mac[6];
WiFi.macAddress(mac);
Serial.print("MAC address: ");
Serial.print(mac[5],HEX);
Serial.print(":");
Serial.print(mac[4],HEX);
Serial.print(":");
Serial.print(mac[3],HEX);
Serial.print(":");
Serial.print(mac[2],HEX);
Serial.print(":");
Serial.print(mac[1],HEX);
Serial.print(":");
Serial.println(mac[0],HEX);
}
void printCurrentNet() {
// print the SSID of the network you're attached to:
Serial.print("SSID: ");
Serial.println(WiFi.SSID());
// print the MAC address of the router you're attached to:
byte bssid[6];
WiFi.BSSID(bssid);
Serial.print("BSSID: ");
Serial.print(bssid[5],HEX);
Serial.print(":");
Serial.print(bssid[4],HEX);
Serial.print(":");
Serial.print(bssid[3],HEX);
Serial.print(":");
Serial.print(bssid[2],HEX);
Serial.print(":");
Serial.print(bssid[1],HEX);
Serial.print(":");
Serial.println(bssid[0],HEX);
// print the received signal strength:
long rssi = WiFi.RSSI();
Serial.print("signal strength (RSSI):");
Serial.println(rssi);
// print the encryption type:
byte encryption = WiFi.encryptionType();
Serial.print("Encryption Type:");
Serial.println(encryption,HEX);
Serial.println();
}

Answer 1

first of all depends of your arduino board ,but if you have a shield I assume that you have an arduino uno, for example.
Now you need to write a web service in php for example ,that response the value stored in mysql after a query.
assuming this : Arduino web client
you need to create in you server one file named ledstatus.php so the call is
www.yourwebserver/ledstatus.php?stat=led1
stat is a command to read stat of led
your php file , after mysql query simple response an integer value 0 or 1 with echo ...
now your led is set :
set const int ledPin = 13;
pinMode(ledPin, OUTPUT);
and in this part of code setting web request
client.println("GET /ledstatus.php?stat=led1 HTTP/1.1");
client.println("Host: www.yourwebserver");
client.println("Connection: close");
client.println();
and in this code read a request reponse
void loop()
{
// if there are incoming bytes available
// from the server, read them and print them:
if (client.available()) {
char c = client.read();
Serial.print(c); // to see the value
digitalWrite(ledPin, atoi(c));
// atoi is a function to convert ascii to integer
}
while(true);
}
Hope this help you