This article is aimed to design and demonstrate a simple 5 Channel IR Remote Control System to drive five loads. The input signals or the commands are sent from a transmitter using IR transmission and received by the IR receiver, processed and used to drive the loads. At both the transmitter and receiver, a microcontroller is used to process the signals.
- 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 operates on the basis of infrared communication. Signals are transmitted utilising an infrared signal as the carrier in IR communication. The microprocessor processes the switch input signal, which is then encoded by the encoder, modulated, and transmitted by the transmitter. The IR receiver demodulates the modulated signal, the decoder decodes it, and the microcontroller processes it to control the output loads at the receiver.
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?
When the circuit is powered, the compiler with initialize the stack pointer and other variables and calls the main function. It scans the input pins, i.e. the signals from the switch.
In case any of the switches is pressed, as per the program, the compiler assigns the corresponding 4 bit value to 4 pins of the output port, i.e. The required 4 bit output signal is generated which is fed to the data input of the encoder.
After that, the encoder turns the 4 bit parallel data into serial data, generating a code for each parallel data input. The encoder’s output is connected to the timer 555’s reset pin, causing the timer to run only when the encoder’s output is present. The timer generates a modulated 38 KHz IR signal, which is then used 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 TSOP 1738 or the IR receiver receives the transmitted IR signal and demodulates it using a pin diode and filter configuration. The receiver’s output is fed into the decoder’s input, which examines the data at least three times before sending a high pulse to the VT pin to signify a legitimate transmission. The serial data input is subsequently converted to 4 bit parallel data output by the decoder. The microcontroller is booted and the input pins are examined in the meanwhile. The compiler assigns a high logic signal to the associated input pin of the relay driver for a certain 4 bit input signal.The Darlington array IC in the relay driver ULN2004 changes the voltage level of the received input signal to give a low voltage signal at the appropriate output pin. As current flows through the relay coil linked to that output pin, the armature shifts from its initial position to complete the circuit, and the lamp begins to shine (not shown in the picture). This procedure is the same for turning on all other lighting.
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.
