An application solution using infrared communication in automatic sensing for use in bathroom sanitary wares. A main circuit board emits an infrared pulse signal on one side to detect a user. After a user is detected, the main circuit board produces a group of pulse collated code opening valve signals to drive another infrared emitting diode to send this collated code. The infrared receiving diode on the slave board receives this collated code, transforms it into a pulse signal and then transmits it to the chip for procession. If the collated codes agree with each other, the solenoid valve can be controlled to open or close the valve. At the same time, the collated code is returned to the main circuit board, which consequently stops emitting the collated code signal for opening the valve.