IR based Speed control of Single Phase AC motor using a Microcontroller 8051

[Vedant Gala]

Hi all,

My project is to create an infrared remote to change the speed and switch on/off of a cap start/run type single phase induction motor operating at AC mains (230V, 50Hz).

I have worked out the controlling the speed of the motor part (using a solid state relay to control phase angle of the stator voltage) but now I have a different challenge.

Let me explain the scenario.

• User presses a button on the remote (say to increase the speed of motor).
• The remote transmits via IR some signal (maybe encoded?)
• There is a receiver at the other end that picks this up,(if required decodes it)
• This information is fed to a microcontroller via an interrupt
• the microcontroller according to it's program chooses one of many different delay values to use and fire a Solid state relay (opto-isolator + triac combination) and hence speed is changed

The challenge is in steps 2 and 3.

I researched that I have to use some kind of protocol (ex. RC5), that uses a particular encoding (ex. Manchester) and use that same at the receiver part.

To clarify further, I don't want to send some particular information from transmitter to the receiver.
Any kind of signal that I can then program my microcontroller to act upon when received will fit the purpose.
Also, a single motor is to be used as output device. However there are three different signals that will be input to the microcontroller (as well as provide a single interrupt whenever any signal is incident). These are for three following operations that will be performed on the motor:

• Switch motor ON/OFF
• increase speed of motor
• decrease speed of motor

Can I not use my own encoding and timer to get desired 38kHz frequency? Because like really I don't need features like security or ... say 10 buttons... I need just 3-4 buttons.

But yes at the same time I do want it to function like a normal remote control.

I need more clarity on this.

I saw various options online:

1. Using HT12A and HT12D encoder decoder ICs
2. Using 555 timer
3. Using another microcontroller
4. Using unused/already existing remotes

Also can I use 3 different IR transmitters transmitting at different frequencies, and 3 different TSOP receivers connected to three different ports of the microcontroller?

Sorry for a somewhat vague question... I'm a newbie in embedded systems and electronics as a whole.

Thanks in advance!

Best Regards,
Vedant