摘要 |
A method of operating a contact sensor and a method of calibration of a contact sensor. The contact sensor comprises an array of discrete and spaced apart sensing elements (102, 202) connected to a resistive element (101, 201) with the location or size of a contact being detectable by measurement of one or more electrical parameter(s) relating to impedance steps along the resistive element (101, 201) is described. The method of operating involves determining a length of the sensing element between the contact and the resistive element and using this to compensate for a parasitic resistance present in the measured resistance of the resistive element. The method of calibration comprises applying one or more calibration contact(s) at a plurality of locations across the sensing elements (102, 202) to be calibrated; monitoring changes in at least one electrical parameter during the time that the calibration contact(s) are applied; and recording information relating to variation in the at least one electrical parameter, the information allowing assessment of the variation in each impedance step across the measured sensing elements. This enables the later use of the sensor to take into account any variation in the impedance steps. |