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Remote Controlled Fan Regulator using ATmega8 microcontroller

This device can be used to remotely control the speed of an AC fan and to switch it on or off. The remote control is a cheap NEC Format remote, usually supplied with small DVD players. Three buttons are used to command the circuit. The UP key increase the fan’s speed while the DOWN key decrease it. The ENTER key is used to switch on or off the fan. The unit provides 10 way speed control from 0 to 9. The current speed is displayed in a seven segment display. The yellow LED on the PCB indicates the power status of the load. If the load is switched off using the R/C then the LED will also be switched off.

In the Video below you can check out the project in action.

The main parts of the circuit is labeled below.

  1. The seven segment display used to show the current speed level.
  2. The TSOP1738 sensor is used to pick up commands from remote control.
  3. The Yellow LED indicates the power status of the load.
  4. OUT – Here the AC load is connected in series. Tested on 220v 50Hz AC line.
  5. IN – Power supply from a 12-0-12 transformer is applied here.
  6. MCU – ATmega8 AVR 8 bit Microcontroller.
  7. SWITCH – Manual Switch used to operate the unit without the remote control.

rc fan thumb

Construction of Remote Controlled Fan Regulator.

You can make the circuit as per the schematic on any general purpose PCB. To ease your job we are giving the PCB Layouts too, so that you can make the PCB at your home using the Etching Method. You may also have the PCBs made from any fab house too. To further easy the job and save your money we have already made the PCBs from a good fab house and they are available for purchase at very low cost.

Start assembly process by first soldering the jumper1. Then you can mount the resistors. After that solder the diodes, remember to properly orient the diodes. They are polar and don’t work if installed other way round. Then solder the IC U4 and U2, this time too take care of the orientation. The small round circle on the IC package marks the PIN number 1.

After that you can solder the ceramic disk capacitors, the 16MHz crystal, 7805, Triac, TSOP Sensor, Display. Finally Connect the 12-0-12 Transformer and apply power. The display should show ‘0’. Then you can press the up/down key in remote control to adjust the speed. The display should change accordingly. This ensures that the circuit is running properly.

Its time to connect a real AC load. Connect a 220V 100W incandescent lamp (NO CFL Please). As shown in the above wiring diagram. Replace the fan with bulb because its easier to test.

Never Touch any part of the circuit when AC load is connected. It can give you a fetal shock !!!

Now you can can use the remote control to increase/decrease the lamp’s brightness using the remote control. You can also switch it on and off using the ENTER key.


If the unit does not respond to the remote control signals then look for the following.

  1. AVR ATmega8’s Fuse BIT is programmed to
    • HIGH=0xC9 LOW=0xFF
  2. AVR is clocked with 16MHz crystal (other value won’t work)
  3. Remote Control is NEC Format Only (Chinese DVD/CD player remote works good, TV Remote Generally do not work as these are RC5 coded)
  4. Remote Key codes has been feed to rckey.h file. Build and run this demo and press UP,DOWN and ENTER keys to get their keycode and put them in rckeys.h file. All remotes available in market has random keycode, so This part is very important. After editing the rckeys.h file the project must be Rebuild. (I hope you know what does that means).
  5. IR sensor is of good quality and must be labeled TSOP1738 (other values won’t work).
  6. If you get a KIT from us then most of the problem do not arise.

hobby remote

Hobby Remote Control (NEC) is available from our online store.

Part list for Remote Controlled Fan Regulator.

Part List
01330 ohm resistor (8 Nos)R2-R9
024k7 Resistor (2 Nos)R1, ,R11
031K ResistorR12
0439 ohm ResistorR13
051K5 ResistorR15
0622pF Ceramic Disk Capacitor (2 Nos)C1,C2
070.1uF Ceramic Disk Capacitor (3 Nos)C3,C5,C6
08470uF 50v Electrolytic CapacitorC4
0916 MHz Crystal Half SizeX1
101N4007 Diode (6 Nos)D2,D3,D4,D5,D6,D7
11LED 5mm Any ColourD1
12MCT2E Opto CouplerU4
13MOC3021 Opto Triac DriverU2
14ATmega8-16PU General purpose 8 bit MCUU1
15Triac BT136U3
167805 Voltage RegulatorU5
17Common Anode DisplayDISP11
18TSOP1738 IR SensorX2
19220V AC to 12-0-12 Centre Tapped Transformer (NOT Included in KIT)
20Hobby Remote Control (NEC)

Buy Remote Controlled Fan Regulator Kit.

For more detail: Remote Controlled Fan Regulator using ATmega8 microcontroller

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