<?php 

$mArray = [
    "distance" => "8",
    "humidity" => "58",
    "moisture" => "998",
    "temperature" => "29.00"
];

//$data = { "distance" : "8", "humidity" : "58", "moisture": "998", "temperature": "29.00" };
// JSON encoded

echo $mArray    ;

// curl -X PATCH -d '{}' \
//   'https://smartirrigation-b7476.firebaseio.com/readings.json'

?>