Circuit Description of infrared (IR) remote controller ..Read more http://electronicsproject.org/infrared-remote-controller/

Transmitter section: – The transmitter circuit of infrared (IR) remote controller is built around IC 741 (IC₁) wired as frequency square wave oscillator. Gate pulse from pin no 6 of IC₁ is given to gate of SCR₁ to drive IR LED₁. Variable resistor VR₁ is used to vary the generated frequencies.

Receiver Section: – The receiver circuit of infrared (IR) remote controller consist an IC 741, photo transistor (T₁) and medium power transistor (T₂).

Photo transistor receives the transmitted signal and given to pin 2 of IC₂ for amplification. The amplified output from pin 6 of IC₂ is given to base of relay driver transistor (T₂) through non-polarized capacitor C₅, diode D₁ and resistor R₈. Variable resistor VR₁ is used to match the transmitting and receiving 

Resistors (all ¼-watt, ± 5% Carbon)

R₁,R₂ = 100 KΩ

R₃, R₅, R₈ = 1 KΩ

R₄ = 15 Ω

R₆ = 22 KΩ

R₇ = 10 MΩ

VR₁ = 1 MΩ

VR₂ = 2.2 MΩ

..Read more http://electronicsproject.org/infrared-remote-controller/
                                                                  Capacitor

₄ = 0.1 µF

C₂ = 1 µF/100V

C₅ = 2.2 µF/16V

Semiconductors

IC₁, IC₂ = 741

SCR₁ = SN050

T₁ = photo transistor

T₂ = SL100

D₁, D₂ = 1N4001

Miscellaneous

RL₁ = 15V, 500Ω Relay

IR LED

..Read more http://electronicsproject.org/infrared-remote-controller/