Nowadays home automation system is an emerging technology that operates the electrical appliances and loads remotely by using advanced controllers with proponent communication technology. This is an advancement of the conventional mechanization process wherein human efforts are needed to operate the electrical devices or appliances . Control capability is more sophisticated with this automation ranging from low level to high level control. So let us look at this topic in brief with practical examples.
Introduction to Home Automation System
Home automation is the controlling and operating the home appliances such as lighting equipments, kitchen appliances, air conditioning and heating, audio/video systems etc. in either automatic or manual modes conveniently and efficiently. This system uses different types of sensors to sense or detect the parameter status and with the use of centralized controllers it appropriately actuates the loads for prescribed limits or conditions. In addition to the controlling it also provides energy saving, graphical user interface or HMI and security to the homes.
The below figure shows the structure of home-control systems where different sensors corresponding to the home appliances with the appropriate actuators are hard-wired to input/output modules of a central controller. The sensors sense the motion, light, temperature, smoke and other sensing variables using sensing devices like photo detectors, IR sensors, thermocouples, current and voltage transformers, etc. Upon receiving these variables and based on the program, the main or central controller actuates the loads using actuators like motors, switches, relays, and other actuating devices.
These controllers can be compact controller to high-end modular-programmable logic controllers with I/O enlarge capability. For user interface, this automation is integrated with different interfacing modules computer/laptops, smart phones, touch pads, tablet with a user friendly HMI application.
Android Remote Control for Home Automation
As we know that Android is a popular smartphone technology, which has been developing ample mobile applications. So, to turn a smartphone or tablet as a universal remote control in place of conventional remotes is a good idea as this is the most effective and flexible automation. This makes every appliance at home as a potential accessory for smartphones. Android remote control based home automation consists of Android OS operated Graphical User Interface (GUI) with wireless communication modules such as Bluetooth and Zigbee to have control on different home appliances.
The structure of the android home automation is shown in the figure. In this system, different sensors and load controllers in the home are connected to sensors and an I/O control module which has the capability to communicate with a user-controlled device. At the user controlling side, the smartphone or tablet with an android-application-based GUI-controller allows the user to send the desired control signals such as switching a lamp off and on, room temperature maintenance, etc.
Building of this android-based home automation is a simple concept as you can implement this in your home by using cost-effective products like microcontroller and sensors as Do It Yourself project. So let us understand this in brief using Bluetooth communication to control home appliances.
The block diagram below shows the design of Android-based home-appliance control that is implemented by using 8051 microcontroller. This circuit consists of some major blocks like power supply, Bluetooth, microcontroller, relay driver and loads, which are explained below.
Power Supply Block: This block supplies power to the entire circuit by stepping down, rectifying, filtering and regulating the available AC power to a regulated-DC-power supply which is sufficient to operate the microcontroller and other control devices like relay coils. The lamp loads are connected to the direct AC mains through relay contacts.
Bluetooth Modem: It is a Bluetooth stack 2.0 compatible devices which has built-in 2.4 GHz antenna. It is a low power consuming, cost-effective and high performing wireless transceiver device that provides two-way communication and also supports both USB and SPI protocols.
Microcontroller: It is the brain of the system that controls the overall operation of the system. The microcontroller receives the controlling signals from a user phone via the Bluetooth modem, and, based on the program, it controls the loads. It is programmed using embedded C language in Keil software.
Relay Driver, Relays, and Lamps: A set of lamps is connected to the micorocntroller via relays through a relay-driver IC. It is also possible to add other loads on home to this relay, but for demonstration purpose, we have used lamps as loads. Here, the relay-driver IC acts as an intermediate controller to energize different relay coils based on the signals from the microcontroller.
For remote operation – before operating this circuit, the smart phone or android mobile is paired to the Bluetooth attached to the microcontroller. Once both are paired, the controlling signals corresponding to the load to operate it can be sent from an Android remote control or phone. From the touch panel of a GUI interface-based application, if any key or button is pressed, the application sends the corresponding signals to the remote Bluethooth modem.
Then, at the receiver side, the Bluetooth modem receives these signals and processes them according to the code, and finally sends the control signals to the relay-driver IC. This driver IC energizes the respective coils to switch the appropriate loads.
This system is useful for the elderly and physically handicapped people as they face difficulties while operating the loads. So, with this Android-home-control system, they can easily operate the loads with portable Android mobile phones. It is also possible to add a temperature sensor by adding an ADC to the microcontroller to switch on the air-conditioning system depending on temperature variations.
Thus, we hope that the furnished information on wireless home automation using Android mobile might have provided the concept to you in detail. And, also you can just imagine how simple would it be to implement such a system in your home that too at a very reasonable cost by using cost-effective devices.If you want complete circuit or any technical help regarding practical guidance to implement electronic projects or this concept you can reach us by commenting below.
- Android Remote Control for Electrical Appliances by anandtech
- Android Remote Control for Home Automation by joybien