A capacitor sensor array (or grid) over a wireless power transmission coil can include a first set of lines; a second set of lines intersecting the first set of lines; a first multiplexer coupled to provide a charge (e.g. in the form of a DC voltage) from a voltage source to the first set of lines and provide first signals to detect voltages on each line; and a second multiplexer coupled to provide a charge from the voltage source to the second set of lines and provide second signals to detect voltages on each line, wherein an object positioned with respect to the first set of lines and the second set of lines is located. According to some embodiments, a wireless power receive coil and a rectifier circuit can be used in forming a capacitor sensor, to sense the capacitance between the receive and transmit coils for better alignment between the two coils. Other embodiments are also provided.