The objective of this article is to create and showcase a straightforward 5 Channel IR Remote Control System designed for controlling five different loads. The commands or input signals are transmitted from a sender via IR transmission, received by the IR receiver, processed, and subsequently utilized to operate the loads. In both the transmitter and receiver components, microcontrollers are employed to handle and process these signals.
Outline
- Principle behind the Circuit:
- 5 Channel IR Remote Control Circuit Design:
- Circuit Diagram of 5 Channel IR Remote Control System using Microcontroller:
- Transmitter Circuit Diagram:
- How to Operate the Transmitter Circuit?
- Receiver Circuit Diagram:
- How Receiver Circuit Works?
- Applications of 5 Channel IR Remote Control Circuit:
- Transmitter Circuit Diagram:
Principle behind the Circuit:
The circuit functions through infrared communication, where signals are conveyed using infrared signals as the medium for IR communication. The microprocessor takes care of the switch input signal, which is subsequently encoded, modulated, and sent out via the transmitter. On the receiving end, the IR receiver demodulates the modulated signal, the decoder interprets it, and the microcontroller processes it to manage the output loads.
5 Channel IR Remote Control Circuit Design:
The transmitter circuit is made up of three ICs: an Atmel89C51 microcontroller, an HT12E encoder, and a 555 timer.
The microcontroller interfacing is the initial step in the design process. A five-item DIP switch is connected to the microcontroller’s port P1 on the input side. The oscillator circuit and reset circuit are also designed as part of the input circuit design. Two 15pF capacitors are connected to both ends of the crystal oscillator in the oscillator circuit design.
The reset circuit was developed with a 100ms reset pulse width and a 1.2V voltage drop at the reset pin in mind. To meet the requirements, we use a 10K resistor and a 10uF capacitor. The HT12E encoder with its 7 address pins and terminal enable pin connected to ground, and 4 data pins connected to Port 0 make up the output side.
The timed oscillator circuit is designed in the second step of the design. Using a 555 timer, we must create an astable multivibrator. With a desired oscillation frequency of 38 KHz and a capacitor value of 0.01uF, the values of Ra and Rb are 760 ohms and 1.5K, respectively.
The receiver circuit uses the same four ICs as the transmitter circuit: Atmel89C51, HT12D decoder, TSOP1738 IR receiver, and ULN2004 relay driver. The microcontroller interface circuit is designed in the same way as the transmitter circuit, with the exception of the reset circuit and oscillator design.
The decoder and TSOP1738 make up the input circuit in this case. The data input pin of the decoder IC is connected to the output pin of the TSOP 1738, and the four data output pins are connected to the microcontroller’s port P1. To signify transmission, the address pins are grounded, and an LED is connected to the valid transmission pin.
The output circuit consists of the relay driver IC ULN2004 with 5 of its input pins connected to port P2 of the microcontroller and the 5 output pins connected to 5 relays operating 5 lamps.
Circuit Diagram of 5 Channel IR Remote Control System using Microcontroller:
Transmitter Circuit Diagram:
5 Channel Remote Control – Transmitter Circuit
Components Included in this Transmitter Circuit:
List of components and the corresponding values are shown below –
- R1 – 1M
- R2 – 10k
- R3 – 760Ohms
- R4 – 1.5K
- R5 – 100Ohms
- C1, C2 – 15pF
- C3 – 10uF
- C4 – 0.01uF
- C5 – 0.1uF
- S1 – 5 DIP switch
- V1 – 5V
- U1 – AT89C51
- U2 – HT12E
- U3 – LM555
- U4A – 7408 (AND gate)
- Q1 – BC547
How to Operate the Transmitter Circuit?
Upon powering the circuit, the compiler will initialize variables, including the stack pointer, and proceed to call the main function. It will then scan the input pins, representing the signals originating from the switches.
In the event that any of the switches is pressed, in accordance with the program’s logic, the compiler will allocate the corresponding 4-bit value to four pins on the output port. This action generates the necessary 4-bit output signal, which is subsequently directed to the data input of the encoder.
Subsequently, the encoder converts the 4-bit parallel data into serial data, creating a distinct code for each parallel data input. The output of the encoder is linked to the reset pin of the 555 timer, ensuring that the timer functions only when there is an output from the encoder. The timer generates a modulated 38 KHz IR signal, which is then employed to drive the IR LEDs.
Receiver Circuit Diagram:
5 Channel Remote Control – Receiver Circuit
Components Included in this Receiver Circuit:
List of components and the corresponding values are shown below –
- R1 – 100Ohms
- R2 – 50K
- R3 – 10K
- C1 – 10uF
- C3, C2 – 10uF
- V1 – 5V
- U1 – HT12D
- U2 – AT89C51
- U3 – ULN2004
- Q1 – BC547
- J1, J2, J3, J4, J5
How Receiver Circuit Works?
The IR receiver, specifically the TSOP 1738, captures and demodulates the transmitted IR signal using a pin diode and filter setup. The receiver’s output is then directed to the decoder’s input, which scrutinizes the data multiple times before generating a high pulse on the VT pin to confirm a valid transmission. Subsequently, the serial data input is transformed into a 4-bit parallel data output by the decoder.
In the meantime, the microcontroller is initialized, and the input pins are monitored. The compiler designates a high logic signal to the respective input pin of the relay driver based on a specific 4-bit input signal. Within the relay driver, the Darlington array IC, ULN2004, modifies the voltage level of the received input signal to produce a low voltage signal at the appropriate output pin. When current flows through the relay coil connected to that output pin, the armature shifts from its initial position, completing the circuit and causing the lamp to illuminate (not depicted in the image). This sequence is identical for activating all other lights.
Applications of 5 Channel IR Remote Control Circuit:
- This circuit can be used to drive number of loads like lamps.
- This circuit can be modified to drive a toy vehicle or a robot using a motor driver instead of a relay driver.
Limitations of 5 Channel IR Remote Control Circuit:
- This project uses IR transmission which is of low range and requires line of sight communication.
