4-Channel IR Remote Control System Using ATtiny85

Today’s project is about a basic 4-Channel IR Remote Control System Using ATtiny85 Microcontroller which can drive AC loads easily. The input signals are sent from a transmitter (Any Infrared Remote) using IR transmission and received by an IR receiver. On the receiver side, we use a simple and compact ATtiny85 chip for a simpler look at the circuit. We have previously discussed how to upload Arduino code into ATtiny85 without using an Arduino. Go and check it out.

Principle Behind IR Remote Control System

The main working principle behind this circuit is infrared communication. IR communication uses IR signals to transmit signals as a carrier. The input signals of the transmitter switches are processed by the microcontroller first, then it is encoded by the encoder. After that is modulated and transmitted by the transmitter.

Next, the transmitted signal will be demodulated by the IR receiver and decoded by ATtiny85 to control the loads.


Circuit Diagram

4-Channel IR Remote Control System Circuit Diagram
4-Channel IR Remote Control System Circuit Diagram

Components Required

  • Arduino Board (Any)
  • ATtiny85 Microcontroller
  • TSOP1738 Infrared Sensor
  • 7805 Voltage Regulator
  • 5V Relay Module (x4)
  • BC547 NPN Transistor (x4)
  • 1N4007 PN Diode (x4)
  • Resistor (1K, 560, 100)
  • Polar Capacitor (100uF/25V, 47uF/25V)
  • 0.1uF Ceramic Capacitor
  • 2-Screw Terminal (x5)
  • Wires
  • 12V Power Supply

Modulation of IR Signals

Modulation of IR signals is important because there are many other sources of infrared rays when the IR receiver receives the signals. Almost everything that emits heat also emits infrared rays. So the signals from a remote can be interfered with by anything from sunlight, light bulbs and even our own bodies. Here we need to take some measures to ensure that the IR signals will be received by the receiver without any errors.

Now the wave pulses from the IR LEDs have to be modulated just like Analog radio modulates a carrier wave to send a signal. To make the IR LED transmit with a particular frequency, modulation involves here. Then the IR receiver will also work with that frequency in order to ignore the noise signals from other infrared sources.

The encoder part of the remote converts a binary signal into a modulated electrical signal. This electrical signal is then sent to the transmitter. It converts the modulated electrical signal into a modulated infrared signal. The IR receiver then demodulates the infrared signal and converts it back to the binary signal before processing it to the microcontroller.

Normally IR remotes use a modulation frequency of 38kHz. There are a few other sources that have a frequency of 38kHz signal. IR receivers are designed to receive these modulated infrared rays and to ignore all other noise signals of surroundings. The infrared ray covers a broad range of spectrums (700nm to 1mm). Most IR LEDs used in remotes operate between the 850nm to 940nm range, so most receivers are tuned to receive the rays within this range. This is another way that how prevents interference from sunlight and other infrared sources.

Decoding of IR Remote Using Arduino

It is important to decode IR code after modulation of the infrared signal. This is done by knowing the control codes of the remote control because each key of the IR remote generates a unique hexadecimal code that is modulated and sent to the IR receiver.

4-channel IR remote decoding circuit

In the absence of a specific code datasheet, we can simply use an Arduino to easily crack the specific code on the serial monitor. Below the basic circuit diagram and circuit, a connection is shown using the TSOP1738 IR sensor and Arduino Nano.

Arduino Code for Decoding IR Codes

First of all, we need a Library file to run the IR code extractor program i.e. IRremote.h library.

From the serial monitor, we got the specific values of each needed key in decimal values. The long values are negligible, only the short ones are considered. After decoding the remote keys, we can use them in many applications. For example, controlling the home appliances using Arduino.

Working Principle of 4-Channel IR Remote Control System

An infrared remote contains an IR LED that produces wave pulses to send signals to another device. On the other hand, an IR receiver receives these infrared waves for decoding the signals. An infrared receiver contains a photodiode and an amplifier for converting the infrared signals to electrical signals.

IR remote has different keys whereby each key produces a different wave pulse when pressed. The transmitting IR LED will blink very quickly for a fraction of a second when we press any of these buttons. These wave pulses (encoded data) can then be decoded uniquely by the IR receiver so that a specific action can be done, such that changing one channel from another.

Arduino Code

Learn how to upload code into the ATtiny85 microcontroller without Arduino.

4 thoughts on “4-Channel IR Remote Control System Using ATtiny85”

  1. Output video can be possible but tutorial video is not possible. Because all is mentioned in this article. For video you can search youtube

  2. Just go to pcb section there you will find the gerber file, download it and then go to pcbway website which link is mentioned there. Then upload the gerber file to their website and place the order. That’s it

  3. This is a good project, but this help the observers to understand well how it works with the help of a tutorial video in order to understand well how it works with enough details

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