A sensor includes a rectangular conductive sheet. Electrical connectors are connected at each corner of the sheet. A number of non-conductive features, e.g. apertures, are formed in this sheet. In one embodiment, V-shaped features extend from near the corners of the sheet towards the centre of the sheet and then turn towards an adjacent corner. Smaller V-shaped features reside in the area between the larger features and the closest edge of the sheet. In another embodiment, a spider web formation of conductive tracks or paths is provided. This provides hardware correction of pincushion error. It reduces or eliminates the need for software correction of pincushion error.