Remote light switch is the basic concept of home automation system wherein lamps in the home are operated remotely with the use of various wireless technologies like RF, IR, Bluetooth, DTMF, and so on. This automatic room-light controller in homes reduces human efforts to turn the switches on and also conserves electrical energy. This concept of remote operation is exceptionally useful for physically disabled persons, elders and other patients.
It is not our intension to just tell about one particular remote-light switch with one remote technology. But, it is our privilege to describe various remote control technologies to control home lamps with a simple controller. So, readers get several ways to control their homes according to their convenience of implementing their homes. Here, we describe several methods to control lamps in homes and all these are cost-effective projects.
1. TV Remote Operated Remote Light Switch
This system uses a conventional TV remote to operate lights so that it reduces extra money to buy a separate remote for lamp control. It is an IR-based remote that sends specially-coded infrared data for every button being pressed to the receiver, i.e., a series of pulses with varying width are transferred from this remote at a particular frequency if we press any key on it. So this data received and decoded at the receiver side does some useful work, such as lamp control in this case.
This system uses 8051 microcontroller as a central processing unit, so it receives an input and correspondingly controls the final control devices. The power supply from the mains is rectified, filtered and regulated to the electronic components operating range and also given to the microcontroller. Lamps are powered directly with the mains supply, but switching the signals is controlled through the microcontroller.
When any key is pressed on the TV remote, it generates an RC5 code at a certain frequency approximately 38 KHz. This coded data is transferred to the receiver side where TSOP is attached with the main controller. The TSOP receiver receives only 38 KHz frequency signals, and therefore, it receives the code sent from the remote, and sends that to the microcontroller.
The microcontroller is programmed in such a way that it decodes these series of pulses and correspondingly sends command signals to the relay driver IC. A set of lamps are connected to various relays, and these relay coils are energized by the microcontroller signals. Hence, depending on the signals from the microcontroller, the relay driver turns appropriate lamp so that programmable switching of loads takes place.
In this way, by using a TV remote, one can turn on or off their lamps in homes by using a microcontroller.
2. RF based Remote Light Switch
As an IR system needs a direct line of sight so it is a useful indoor system, whereas RF system doesn’t require any line of sight and allows us to operate even from another room depending on the RF range. But these systems are expensive than the IR-based control. Hence, this project is advanced than the above discussed project.
This system consists of both transmitter and receiver sections. In the transmitter side, the input control signals are transmitted in the form of RF signals, whereas the receiver part receives these RF signals and controls the actuators to switch the lighting system on. In both the sections, a microcontroller acts as a master that controls the slave devices.
In the transmitter section, a set of switches in proportion to the loads are connected to the microcontroller that sends the digital information according to the button pressed to the encoder. The encoder encodes this series of data to the packet data, and then transfers it to an RF transmitter; from there this data is passed to the receiver.
At the receiver side, an RF module receives and demodulates the transferred data and gives it to the decoder in which this packet data is converted back to original binary data. This binary data is received by the microcontroller, which processes it, and based on the program, it sends control signals to the opto- isolators. Here, the Opto- isolator triggers the triac, so it starts conducting resulting in a closed-path current that makes lamp glow. In this way, based on the button pressing in the remote, corresponding lamps as well as other home appliance controlling is possible.
3. Android Based Remote Light Switch
Android-based remote operation of a light switch uses Android mobile with a graphical user interface application in it. This operation of lights controlling is simple and friendly for every mobile user as it reduces the need to carry a remote every time.
In this way, at the receiver side, a microcontroller is attached with lamp loads wherein a Bluetooth modem continuously gives signals to the microcontroller. Before getting the input signals from the Android mobile, first we have to pair that mobile with a Bluetooth modem attached to the loads.
When we send a corresponding input from the android mobile, the Bluetooth modem receives it and gives it to the microcontroller. Based on the program written, the microcontroller sends command signals to the relay driver that correspondingly turns the lamp on.
4. DTMF based Remote Light Switch
This is another method of implementing a remote-light switch with the help of DTMF tones in mobiles. By using this system, we can also control lamps remotely by attaching a DTMF-based mobile with a control unit – even if the lamps are some hundreds of miles away from home by keeping the mobile in an automatic answerable mode. This is a simple project that requires less hardware compared to the above project, but needs a mobile phone to be attached to this system.
In this remote operation of light, the DTMF tones are decoded by a DTMF decoder, which is transferred to a microcontroller as input signals. If we connect to this mobile from any location which is attached with the microcontroller, it automatically answers the call. When we press any key in our mobile, it generates the DTMF tones that are subsequently decoded by the decoder and are transferred to the microcontroller. Based on the microcontroller’s program, it controls the load by sending command signals to a relay driver IC. It is also possible to control the lamps by generating key tones in the mobile without getting any call from any mobile.
This is all about the remote light switch implementation with the use of IR, RF, Android and DTMF technologies. We hope that you have got a better understanding of this concept with the real-time application-based projects. Furthermore, if you have got any doubts on implementing these projects, you can contact us by commenting below.