US Patent 8104113 Position-sensing detector arrangement for controlling a faucet

A faucet arrangement includes a sensing device for sensing a presence of a user of a spout. The sensing device includes an infrared emitter installed such that a direction of emission of the emitter is oriented an angle of approximately between 5 and 15 degrees relative to a vertical direction. A receiver receives a diffused infrared energy from the emitter. A control device is in communication with the receiver and controls a flow of liquid through the spout dependent upon an angle at which the diffused infrared energy is received by the receiver.