Infrared (IR)

Infrared (IR)

Many electronic devices communicate without wires.

For example:

• TV remote controls
• Air conditioners
• Media players
• Projectors
• Smart home devices

Most of these devices use Infrared (IR) communication.

Infrared communication uses invisible light signals to transfer information between devices.

The Infrared category allows a D1 R32 to:

 Receive signals from remote controls

 Detect button presses

 Read command codes

 Transmit infrared signals

 Control other IR-enabled devices

 Create programmable remote-control systems

 Build wireless robot controllers

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Introduction

Imagine pressing a button on a TV remote.

The television immediately changes channel.

No wires are involved.

What happened?

The remote transmitted an invisible infrared signal.

The television received that signal and interpreted it as a command.

The exact same process can occur between a remote control and the D1 R32.

Remote Control

↓

Infrared Signal

↓

IR Receiver

↓

D1 R32

The D1 R32 can also perform the opposite operation:

D1 R32

↓

IR Transmitter

↓

Infrared Signal

↓

Television / Device

This allows your projects to both receive and send infrared information.

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What Is Infrared (IR)?

Infrared is a type of light that cannot be seen by the human eye.

Devices use this invisible light to transmit information.

Instead of sending text or pictures, infrared usually sends:

• Commands
• Button presses
• Device instructions
• Control signals

---

Everyday Examples

Examples of devices that commonly use IR include:

 Television remotes

 Air conditioner remotes

 Audio systems

 DVD players

 Projectors

 Some robotics systems

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Why Use IR?

IR communication allows devices to communicate wirelessly over short distances.

Examples include:

• Turning LEDs on and off
• Controlling robots
• Reading remote buttons
• Creating programmable remotes
• Sending commands between devices

---

Understanding IR Communication

All IR systems use the same basic communication pattern.

Transmitter

↓

Infrared Signal

↓

Receiver

The transmitter sends information.

The receiver detects and interprets that information.

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Infrared Category

[INSERT CATEGORY IMAGE HERE: Infrared Category]

Figure 13.1 – Blocks available in the Infrared (IR) category.

The category is divided into two major sections:

IR Receive

Receives and interprets infrared signals.

IR Send

Transmits infrared signals.

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Learning Model

The category can be understood using two workflows.

Receiving

SETUP

↓

RECEIVE

↓

READ

↓

ACT

Sending

SETUP

↓

TRANSMIT

↓

CHECK

---

Part 1: Receiving Infrared Signals

IR Receive Setup

[INSERT BLOCK IMAGE HERE: IR Receive Setup]

Before receiving signals, the IR receiver must be configured.

Conceptually:

Choose Protocol

↓

Connect Receiver

↓

Receive Signals

---

Actual Generated Python

Clu-Blocks Pro creates an infrared receiver object.

import irremote

The generated code depends on the selected protocol.

NEC 8-bit

ir_rx = irremote.NEC_RX(26,8)

NEC 16-bit

ir_rx = irremote.NEC_RX(26,16)

NEC

ir_rx = irremote.NEC_RX(26,0)

RC5

ir_rx = irremote.RC5_RX(26)

Protocol	Generated Python
NEC 8-bit	irremote.NEC_RX(26,8)
NEC 16-bit	irremote.NEC_RX(26,16)
NEC	irremote.NEC_RX(26,0)
RC5	irremote.RC5_RX(26)

 Setup first. Receive second.

---

Why Setup First?

Imagine trying to listen to a radio that isn't turned on.

You would hear nothing.

The same applies to IR communication.

The receiver must be configured before it can detect information.

---

IR Protocols

The receiver can be configured to understand different communication formats.

Examples include:

• NEC 8-bit
• NEC 16-bit
• NEC
• RC5

For beginners, the important idea is:

Receiver Setup

↓

Protocol

↓

Receive Data

---

Receiving Infrared Data

[INSERT BLOCK IMAGE HERE: Get Received Code]

After a signal is received, information can be extracted from it.

Conceptually:

Receive Signal

↓

Extract Information

↓

Use Information

---

Actual Generated Python

The block can access four confirmed positions of the received code.

ir_rx.code[0]

ir_rx.code[1]

ir_rx.code[2]

ir_rx.code[3]

Selection	Generated Python
Position 1	ir_rx.code[0]
Position 2	ir_rx.code[1]
Position 3	ir_rx.code[2]
Position 4	ir_rx.code[3]

---

Detecting New Data

[INSERT BLOCK IMAGE HERE: Data Received?]

Before reading information, a program can check whether new IR data is available.

Conceptually:

Signal Received?

↓

True / False

---

Actual Generated Python

ir_rx.any()

Example:

IF Signal Received

↓

Read Command

This prevents the program from trying to read information when no signal is present.

---

Enabling and Disabling the Receiver

[INSERT BLOCK IMAGE HERE: Receive Control]

The receiver can be enabled or disabled.

---

Actual Generated Python

Enable receiving:

ir_rx.enable(True)

Disable receiving:

ir_rx.enable(False)

State	Generated Python
Enable	ir_rx.enable(True)
Disable	ir_rx.enable(False)

---

Enabled

Listening for Signals

Disabled

Ignoring Signals

---

Receive Timeout

[INSERT BLOCK IMAGE HERE: Receive Timeout]

The timeout setting controls how long the receiver waits for communication.

---

Actual Generated Python

ir_rx.timeout(1000)

Example:

1000 milliseconds

Conceptually:

Wait for Signal

↓

Signal Arrives?

↓

Yes / Timeout

---

Understanding Hexadecimal Commands

Infrared remotes often use hexadecimal command codes.

Example:

0x45

The:

0x

prefix indicates hexadecimal notation.

---

 IR Remote Control Button Codes

[INSERT IMAGE HERE: IR Remote Control]

Figure. IR remote control used in Clu-Blocks Pro exercises.

Complete Remote-Control Reference

Button	Hex Raw	Hex Command
1	0xba45ff00	0x45
2	0xb946ff00	0x46
3	0xb847ff00	0x47
4	0xbb44ff00	0x44
5	0xbf40ff00	0x40
6	0xbc43ff00	0x43
7	0xf807ff00	0x07
8	0xea15ff00	0x15
9	0xf609ff00	0x09
*	0xe916ff00	0x16
0	0xe619ff00	0x19
#	0xf20dff00	0x0D
UP	0xe718ff00	0x18
LEFT	0xf708ff00	0x08
RIGHT	0xa55aff00	0x5A
DOWN	0xad52ff00	0x52
OK	0xe31cff00	0x1C

---

Course Rule

 Use Hex Command values unless the exercise specifically requires the full raw code.

Example:

Button 1

Hex Raw: 0xba45ff00

Hex Command: 0x45

---

First IR Experiment

The first IR activity should focus only on identifying commands.

Step 1

Press a remote button.

Step 2

Receive the command.

Step 3

Display the command through Serial.

Step 4

Compare it with the reference table.

Example:

Press Button 1

↓

Receive Command

↓

0x45

↓

Serial Monitor

---

Using Commands to Control Projects

Once commands can be identified, Logic blocks can be added.

Example:

Received Command

↓

Equals 0x18?

↓

True

↓

Move Robot Forward

Another Example:

Received Command

↓

Equals 0x52?

↓

True

↓

Move Robot Backward

---

Part 2: Sending Infrared Signals

IR Send Setup

[INSERT BLOCK IMAGE HERE: IR Send Setup]

Before transmitting infrared signals, the transmitter must be configured.

Conceptually:

Choose Configuration

↓

Set Power

↓

Transmit

---

Actual Generated Python

NEC

ir_tx = irremote.NEC_TX(26,False,90)

NEC Inverted

ir_tx = irremote.NEC_TX(26,True,90)

RC5

ir_tx = irremote.RC5_TX(26,90)

Configuration	Generated Python
NEC	NEC_TX(26,False,90)
NEC Inverted	NEC_TX(26,True,90)
RC5	RC5_TX(26,90)

---

Sending Commands

[INSERT BLOCK IMAGE HERE: Send Command]

The send command block transmits structured infrared information.

---

Actual Generated Python

ir_tx.transmit(0,0,0)

The block contains:

1. Command Code
2. Address Code
3. Control Bit

Conceptually:

Command

+

Address

+

Control

↓

Transmit

---

Sending Raw Codes

[INSERT BLOCK IMAGE HERE: Send Raw Code]

Sometimes a project already knows the exact code it wants to send.

---

Actual Generated Python

ir_tx.transmit(raw=0x1234)

Conceptually:

Hex Code

↓

IR Transmitter

↓

Receiving Device

---

Sending Pulse Sequences

[INSERT BLOCK IMAGE HERE: Send Pulses]

Pulse transmission allows exact timing information to be sent.

---

Actual Generated Python

ir_tx.transmit(
pulses=[9000,4500,563,563]
)

Example pulse sequence:

9000, 4500, 563, 563

Conceptually:

Pulse Pattern

↓

Infrared Signal

 Advanced Topic: Pulse sequences should usually be introduced after students understand command-based transmission.

---

Command vs Raw vs Pulses

Method	Generated Python	Use
Command	transmit(command,address,control)	Structured commands
Raw	transmit(raw=...)	Raw hexadecimal code
Pulses	transmit(pulses=[...])	Explicit pulse timing

 Hex Command values are usually the easiest way for beginners to work with IR communication.

---

Checking Transmission Status

[INSERT BLOCK IMAGE HERE: Transmit Status]

Programs can check whether the transmitter is busy.

Actual Generated Python

ir_tx.busy()

Conceptually:

Still Sending?

↓

Yes / No

---

Using Serial While Learning IR

For this category, Serial communication should remain central.

Step 1

Press a remote button.

Step 2

Receive the command.

Step 3

Send the command to the Serial Monitor.

Step 4

Compare it with the reference table.

Step 5

Use that command in Logic.

---

Learning Pattern

RECEIVE

↓

OBSERVE

↓

IDENTIFY

↓

COMPARE

↓

ACT

This makes invisible communication visible.

---

IR Receive vs IR Send

IR Receive	IR Send
Creates ir_rx	Creates ir_tx
Detects signals	Creates signals
Reads commands	Sends commands
Uses any()	Uses transmit()
Uses enable()	Uses transmitter setup
Uses timeouts	Uses transmit status
Remote → D1 R32	D1 R32 → Device

---

Infrared vs Radio

Infrared	Radio
Uses invisible light	Uses radio signals
Usually line-of-sight	Usually does not require line-of-sight
Common in remotes	Common in robotics
Remote-control focused	Device-to-device focused

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Key Vocabulary

Term	Definition
Infrared (IR)	Invisible light used for communication
IR Receiver	Device that detects infrared signals
IR Transmitter	Device that sends infrared signals
Protocol	Communication format used by IR devices
NEC	Common infrared communication protocol
RC5	Another infrared communication protocol
Command	Instruction carried by an IR signal
Hexadecimal	Base-16 number format
Raw Code	Complete IR communication value
Pulse Sequence	Timing pattern used in IR communication

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Summary

In this lesson, you learned how infrared communication allows devices to exchange information using invisible light.

You explored how to:

 Configure an IR receiver

 Receive remote-control information

 Identify hexadecimal command codes

 Configure an IR transmitter

 Send infrared commands

 Use remote controls to trigger actions

 Build programmable remote-control systems

 Understand the difference between receiving and transmitting infrared signals

Infrared communication powers many everyday devices such as televisions, air conditioners, projectors, and media players. By learning how to receive, interpret, and transmit infrared signals, you can create projects that interact with the same technology used in real-world electronics.

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Key Takeaway

Infrared communication allows a D1 R32 to receive and transmit invisible light signals, just like a programmable remote control.

By learning to receive commands, identify button codes, transmit signals, and trigger actions, you can create projects that interact with real-world electronic devices and build your own custom remote-control systems.