connect_error) {
die("Connection failure:" . $conn->connect_error);
}
// This SQL query lists all the sensors in your database. Thus, each time a new sensor is configured, it is automatically added to the dashboard.
$sql = "SELECT DISTINCT Sensor FROM ACTIVITY ORDER BY Sensor ASC";
$result = $conn->query($sql);
//For each result of the query, we display a graphical area containing the key information of this sensor.
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc()) {
$SensorUrl = urlencode($row["Sensor"]);
/*
We will display two important pieces of information on the dashboard for each sensor:
1. The connectivity status "Connected" or "Offline"
To check this, we verify if the last 'reading_time' is less than 61 seconds old.
Normally, 60 seconds would be enough, but we add 1 second to account for the latency delay associated with data recording on the server.
2. The production flow status "Production" or "Stopped"
To determine this, we will compare the last two 'counter' values, ensuring that the counter increments
AND that the most recent recording is less than 61 seconds old (using the same logic as before).
*/
$lastTwoValuesSql = "SELECT counter FROM ACTIVITY WHERE Sensor = '" . $row["Sensor"] . "' ORDER BY reading_time DESC LIMIT 2";
$lastTwoValuesResult = $conn->query($lastTwoValuesSql);
$lastTwoValues = array();
while ($valueRow = $lastTwoValuesResult->fetch_assoc()) {
$lastTwoValues[] = $valueRow["counter"];
}
$lastReadingSql = "SELECT MAX(reading_time) AS last_reading_time FROM ACTIVITY WHERE Sensor = '" . $row["Sensor"] . "'";
$lastReadingResult = $conn->query($lastReadingSql);
$lastReadingRow = $lastReadingResult->fetch_assoc();
$lastReadingTime = strtotime($lastReadingRow["last_reading_time"]);
$currentTime = time();
$timeDifference = $currentTime - $lastReadingTime; // Duration in seconds
if (count($lastTwoValues) === 2 && $lastTwoValues[0] != $lastTwoValues[1] && $timeDifference < 61) {
/* If there are exactly two last values, and they are different, and the time difference is less than 61 seconds, set the status to 'PRODUCTION'
and display a green dot for visual indication.
*/
$prod_or_stop = "PRODUCTION
";
} else {
// Otherwise, set the status to 'STOPPED' and display a red dot as a visual indicator of the stoppage.
$prod_or_stop = "STOPPED
";
}
// Logic for the connectivity status : checks if the time difference is less than 61 seconds.
$connexion = ($timeDifference < 61) ? "CONNECTED
" : "OFFLINE
";
/* Date formatting depending on whether it is today's date.
This line checks if the date of the last reading ($lastReadingTime) is the same as today's date.
If the dates match (meaning the last reading was today), it sets the format to show only the time ("H:i").
If the dates do not match (meaning the last reading was on a different day), it sets the format to show the date and the time ("d/m/Y H:i").
This approach allows a user-friendly date display logic.
If the event occurred today, the user sees only the time of the event, providing immediate context that it was recent.
*/
$dateFormat = (date("Y-m-d", $lastReadingTime) == date("Y-m-d")) ? "H:i" : "d/m/Y H:i";
$formattedDate = date($dateFormat, $lastReadingTime);
$SensorUrl = urlencode($row["Sensor"]);
// Generating a card for each Sensor.
// We provide a direct link to the 'stats.php' page, which allows for viewing information related to this sensor for the current day.
echo '
' . htmlspecialchars($row["Sensor"]) . '
' . $connexion . '
' . $prod_or_stop . '
LAST UPDATE :
' . $formattedDate . '
';
}
} else {
// In case there is no sensor
echo "
No sensor found.
";
}
$conn->close();
?>