Design and production of radio remote control fan stepless speed regulator

This radio remote control fan stepless speed regulator has three major functions: (1) By pressing the button on the transmitter or quickly touching the touch electrode led out of the receiving speed regulation circuit with your hand, the fan power can be turned on or off; (2) By controlling the length of time the button on the transmitter is pressed or the touch electrode is touched, the fan speed can be adjusted steplessly within a certain range, and the speed can be memorized when the control circuit is powered on, so there is no need to readjust the speed every time the fan is turned on; (3) By pressing the dedicated button on the transmitter or closing the dedicated switch of the receiving speed regulation circuit, the fan can be adjusted steplessly in a continuous cycle of 7.64s, which can make the air volume increase or decrease in a burst, and cool breezes, thereby achieving the effect of simulating natural wind.

1. Working Principle

The circuit of the radio remote control fan stepless speed regulator is shown in the figure below. Its core components are two-bit radio remote control special components A1 and A2 and a new touch dimming and speed regulation integrated circuit A3. M is the controlled fan motor drawn for the convenience of explaining the principle.

After the 220V AC mains is limited by C6, limited by VD4, half-wave rectified by VD3 and filtered by C5, it provides about 6V DC to the control circuit. When the B key on the transmitter A1 is pressed (<1s) within the effective distance range, the decoding effective output terminal Io of the receiving module A2 outputs a synchronous positive pulse signal, which is inverted by the transistor VT and injects a negative pulse signal into the ⑤th pin of the A3 control terminal, controlling A3 to output or terminate the trigger signal required by the bidirectional thyristor VS from the output terminal ⑧th pin, completing the "on" of the motor M.

Or "off" control. If the fan is running before pressing the B button on the transmitter, the fan will stop after pressing the button; vice versa. The fan speed is the same as the speed when it stopped last time, and this rule will be maintained as long as the power is not cut off. When the B button is pressed and not released (>18), the circuit phase shifts the speed, and the phase angle corresponds to the speed of the fan motor. The speed phase shift range is 40°-159° (corresponding to the effective value of the motor working voltage 27·200V); when the B button is released, the speed will no longer change and the speed at this moment will be maintained. When the A button on the transmitter is pressed, the output terminal A corresponding to A2 outputs a high level, VT is turned on, and the ⑤th foot of A2 obtains a low level. The speed regulation circuit enters a continuous cycle state, and the speed change cycle is 7.64s, thereby realizing the simulation of natural wind control. If you want to release the simulated natural wind state, just press the B button of the transmitter. At this time, the A terminal of A2 returns to a high level, the B terminal (suspended) becomes a low level, and the M speed is locked unchanged; click the B button of the transmitter again, and M will automatically stop.

In the circuit, the touch electrode and the human body protection resistors R2 and R3 form a touch control circuit. The owner can achieve the same control function as the transmitter B key by touching the touch electrode with his hand. SA is a manual control switch for simulating natural wind. When closed, it generates simulated natural wind, and when open, it releases this function.

2. Component Selection and Production

A1 and A2 use HY986/988A two-position radio remote control special components, and the effective remote control distance can reach 50m. Al and A2 can also be directly replaced by similar products TWH9236/9238. A3 uses CS7232 touch dimming and speed control integrated circuit, and can also be directly replaced by SM7232, BA2103 and other similar products. VS uses TLC336A (3A, 600V) ordinary bidirectional thyristor, and the trigger current is required to be as small as possible to ensure stable and reliable operation. VT uses 9014 or 3DG8 silicon NPN transistors, and β>100 is required. VDI and VD2 use IN4148 silicon switching diodes; VD3 uses 1N4007 silicon rectifier diodes; VD4 uses 6.6V, 0.25W silicon voltage regulator diodes, and the voltage regulator value is required to be accurate. 2CW55, 1N4099, etc. can be selected.

RV uses 470V, 100A (peak current) zinc oxide varistor, which is connected in parallel at both ends of VS to prevent the inductive voltage generated by the fan motor from breaking through VS. R1~R6 - RTX-I/4W carbon film resistors are used.

C1~C4 are all CT1 ceramic capacitors, C5 is CDI1-10V electrolytic capacitor, C6 is high-quality CBB13-630V polypropylene capacitor. SA is a small 1x1 toggle switch.

During production, all circuits except Al are welded in the base cavity of the ordinary desktop fan to be modified. The touch electrode can be processed into a sign plate with aluminum (copper) skin, and glued to the appropriate position of the plastic panel of the fan base with strong glue for easy operation. Series resistors R2 and R3 with insulating tubes are welded on the back of the touch electrode. Its ends are connected to the control circuit. SA can be fixed near the touch electrode. If you want to control the indoor ceiling fan, you can put the receiving control circuit into a small plastic box separately, and fix the touch electrode and SA switch on the box panel; fix the small box on a wall that is easy to operate, connect the 220V mains and the ceiling fan motor through double-strand wires, and it can be put into use.

Note when making: The resistance value of R4 determines the touch sensitivity of the circuit. You can adjust its resistance value according to the actual size of the touch electrode area to obtain satisfactory sensitivity. In principle, the larger the touch electrode area, the smaller the resistance value of R4 should be. In addition, the 220V AC mains must be connected after the phase line and the neutral line are separated as shown in the figure. If they are connected in reverse, the touch function will be lost. Since there is a certain time difference between the circuit voltage regulation and the fan speed change, it is not easy to control the actual speed regulation (especially when adjusting to the maximum speed) accurately.

Therefore, it is recommended to connect a 10-15W, 220V small bulb in parallel at both ends of the fan motor M, and judge the rotation speed according to the light changes; and the light can become a decoration for the fan, killing two birds with one stone.