Remote control fan speed regulator circuit

Circuit working principle: The circuit uses the TSOP1738 infrared receiving module to receive
the infrared signal sent by the remote control. Use a stable 9V power supply. The 220 V AC power supply
is stepped down by the transformer T, and then fully-wave rectified by VD, VD2, and stabilized to
9V by the voltage stabilizing chip 7809. Any button on the remote control can be used to control fan speed.
The pulse output by the infrared receiving module is used as the trigger signal of the timer chip NE555 ( IC .) after passing through R4 and LED
. Ic, connected to a monostable operating mode,
provides a delay for the clock signal of the decimal counter chip CD4017 (lC2).