This is the home automation model using a TV remote (IR communication) .
The prototyped version uses arduino uno as microcontroller, three transistors and relays for switching three 230V/15W bulbs, IR TSOP receiver (1738), old VCR remote controller and some passive components. Modulation is the answer to make our signal stand out above the noise. With modulation we make the IR light source blink in a particular frequency. The IR receiver will be tuned to that frequency, so it can ignore everything else. This project uses NEC protocol based remote controller, that transmits Pulse Position Modulated signal at a carrier frequency of 38KHz. Different protocols have different decoding algorithms. In serial communication we usually speak of ‘marks’ (or burst) and ‘spaces’. The ‘space’ is the default signal, which is the off state in the transmitter case. No light is emitted during the ‘space’ state. During the ‘mark’ state of the signal the IR light is pulsed on and off at a particular frequency. The IR signals are received using TSOP (Thin Small Outline Package). the state of TSOP changes according to the state of ir transmitter I.e. whether it is marks or spaces. The changes in TSOP is detected and processed by the arduino UNO using irremote.lib. When a valid key is pressed arduino switches the state of relay through a MOSFET as a result we get specific bulb glowing.
Encrypted IR communication, resistant to ambient daylight can be utilized for robotic competitions like Robocon where there will be instances for communication between manual and automatic bots;The project idea can also be expanded with GSM based mobile communication for building energy conservation modules. Virtual Grid mapping and swarm intelligence are some of the future prospective of this project.