In one embodiment, a method includes receiving one or more sense signals from a touch sensor of a device, comparing a value associated with the one or more sense signals to a first threshold, and determining, based on comparing the value to the first threshold, whether an object has come within a pre-determined proximity of a first pre-determined location at a surface of the device. The method further includes comparing the value associated with the one or more sense signals to a second threshold and determining, based on comparing the value to the second threshold, whether the object has come within a pre-determined proximity of a second pre-determined location at the surface of the device.