Abstract: A sensing apparatus includes two or more sensor arrangements, a housing which is configured to house the two or more sensor arrangements, a first sensor arrangement which is configured to sense a first property, a second sensor arrangement which is configured to sense a second property, and an output arrangement which is configured to provide an output signal from the sensing apparatus in dependence upon an output of the first sensor arrangement and an output of the second sensor arrangement, the first property is different from the second property, and the sensing arrangement is configured to provide a combined signal output by way of the output arrangement.