private function prepareData()
{
/*
* Using the onboard temperature sensor and the command 'uptime'
* to pull in information about how hot the Raspberry Pi is and
* how long it's been switched on for.
*/
$output = shell_exec('cat /sys/class/thermal/thermal_zone0/temp');
$temp = round($output / 1000, 1);
$output = shell_exec('echo "$(</proc/uptime awk \'{print $1}\')"');
$time_alive = StringHelpers::secondsToTime(intval($output));
// data object
$data = new \stdClass();
$data->temperature = $temp;
$data->uptime = $time_alive;
return $data;
}