...
$res->{sensorsOutput}
....

my $json_file_path = '/tmp/sensordata.json'; # Ensure this path is correct
open my $fh, '<', $json_file_path or die "Cannot open $json_file_path: $!";
my $json_text = do { local $/; <$fh> };
close $fh;
$res->{sensorsOutput} = $json_text;