IR Transmitter Circuit Diagram (Infrared)

Introduction

The IR transmitter is an electronic device that uses infrared light to transmit signals from one device to another. This circuit diagram is widely used in remote control systems, security systems, and home automation projects. The IR transmitter circuit diagram involves the use of an IR LED that emits IR light, which carries the data and can be decoded by an IR receiver. The circuit is designed with a specific frequency range that is used to transmit signals smoothly.

The Infrared IR Transmitter is intended primarily for the testing of infrared receivers. The test is possible in most cases even without having the associated remote control available. Of course, the test will then be limited to just the infra-red sensor device in the receiver, but it is very useful to begin with when it comes to faultfinding in an infra-red controlled system like a TV set or a VCR. The combination of this test transmitter and the simple infrared receiver described elsewhere in this website forms a simple one-channel on/off remote control. The IR Transmitter Circuit Diagram is a diy circuit and one of a simple electronic projects,



Circuit Diagram of IR Transmitter

This IR Transmitter can be designed using a few basic components. The circuit diagram of this project is shown below.

IR Transmitter Circuit Diagram
IR Transmitter Circuit Diagram



More Circuit Layouts





IR Transmitter PCB Layout

IR Transmitter PCB Layout
IR Transmitter PCB Layout

Components List

of IR Transmitter Circuit Diagram

Resistors:

  • R1 = 5.6 k
  • R2 = 270 k
  • R3 = 3.3 k
  • R4 = 22
  • P1= 2.5k preset, horizontal

Capacitors:

  • C1 = 0.0012 uF, pitch 5 mm
  • C2 = 0.1 uF, rpitch. 5 mm
  • C3 = 100 μF, 10 V, radial

Semiconductors:

  • D1, D2, D3 = BAT85
  • D4 = LD271 or LD274
  • Τ1 = BC327

Integrated circuits:

  • IC1 = 74HC4060 (Philips, do not use Texas Instruments)

Miscellaneous:

  • S1 = miniature pushbutton, e.g., Conrad o/n 70 04 79-44
  • Bt1 = 3 V Li-ion battery, 20 mm diameter
  • Case: as appropriate
  • PCB may be made with the aid of the track layout.



Working Explanation

of IR Transmitter Circuit Diagram

Like a ‘real’ remote control unit, the transmitter emits pulses modulated on to a carrier signal of about 36 kHz. Because it is not necessary for the testing purposes outlined above to have a true encoded pulse train (like RC5, RECS80 et al.), the bursts can be made with three counter outputs connected to a diode triplet, D1, D2, D3, acting as a wired OR gate. Schottky diodes are used here because of their inherent low forward voltage drop of just 0.4 V. The 14-stage ripple carry counter, IC1, also contains an oscillator which oscillates at about 36 kHz determined by R2, P1, R1 and C1. The buffered oscillator output at pin 9 supplies carrier (clock) pulses to the driver transistor via R3. If one of the counter outputs is logic high, however, T1 is turned off. In this way, a signal is obtained which, apart from encoding information, resembles that produced by a real remote control unit.

Fast p-n-p switching transistor T1 is used in common-emitter mode to make sure the circuit keeps transmitting even if the battery is almost ‘flat’. In fact, the test transmitter will keep working reliably at 36 kHz at battery voltages down to 1.7 V. Because of the small duty factor of the 60mA peak-pulse through sender diode D4, the average current drawn from the 3 volt Li-ion battery is only about 6 mA when the battery is full, and 2.5 mA when the battery is discharged to 2.5 V. A test signal is emitted when push button S1 is pressed.

The whole circuit including the battery is conveniently built on a compact PCB designed to fit in a special key-fob case available from certain retailers.

Conclusion

In conclusion, the IR transmitter circuit diagram is a crucial component in modern electronic devices. It is a simple and effective way of transmitting signals using infrared light. The circuit has various applications in remote controls, security systems, and home automation projects. The circuit is relatively easy to build, and it requires only a few components, making it accessible to both amateurs and professionals alike. With advances in technology, the IR transmitter circuit diagram will continue to play a significant role in the evolution of modern electronic devices.



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IR Transmitter Circuit Diagram
IR Transmitter Circuit Diagram
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