A dust collection system includes a sensor body, a selection circuit, a detection circuit, and a motor control circuit. The sensor body detachably encircles a cord supplying power to a power tool. The cord includes a neutral conductor and a hot conductor. The sensor body houses sensors that, in response to current flow through the cord, generate sensor signals. The selection circuit generates a positive output signal in response to the sensor signals and generates a negative output signal in response to the sensor signals. The detection circuit generates a current detection signal in response to a comparison of the positive and negative output signals with a threshold. The motor control circuit selectively turns on a motor of the dust collection system in response to the current detection signal.