In one embodiment, a controller includes a processor and a memory, the memory storing logic. The logic is configured to perform, when executed by the processor, operations comprising detecting, in response to driving electrodes of a touch sensor with a first drive signal having a first polarity, a presence of a stylus. The presence of the stylus is detected based on a first sense signal, the first sense signal having a second polarity. The operations further comprise detecting, in response to driving the electrodes with a second drive signal having the first polarity, a second sense signal having a third polarity. The third polarity is an inverse of the second polarity. The operations further comprise driving, in response to detecting the second sense signal having the third polarity, the electrodes with a third drive signal having a fourth polarity. The fourth polarity is an inverse of the first polarity.