🔦 Level 2 – Sensors & IR Control

Project 2.1: "IR Remote Control"

🚀 Project 2.1 – IR Remote Control

🎯 What You’ll Learn

✅ Goal 1: Detect IR button codes.
✅ Goal 2: Control LEDs with IR remote.
✅ Goal 3: Create ON/OFF logic.
✅ Goal 4: Control multiple devices.
✅ Goal 5: Program macro commands.

Key Ideas

IR Receiver: Captures remote signals.
Hex codes: Identify each button.
Logic: Decide actions based on code.
Outputs: LEDs or motors respond.

🧱 Blocks Glossary (used in this project)

import irremote → Load IR library.
ir_rx = irremote.NEC_RX(pin, buffer) → Setup IR receiver.
ir_rx.code[0] → Read received code.
ir_rx.any() → Check if signal exists.
ir_tx = irremote.NEC_TX(pin, repeat, freq) → Setup IR transmitter.
ir_tx.transmit(a,b,c) → Send IR command.

🧰 What You Need

Part	How many?	Pin connection
D1 R32	1	USB cable
IR Receiver	1	Pin 26
Remote Control	1	Standard NEC remote
LED	1	Pin 5

✅ Before You Start

USB cable connected
IR receiver wired correctly
Test print shows:

print("Ready!")  # Confirm serial is working

🎮 Microprojects (5 Mini Missions)

🎮 Microproject 2.1.1 – IR button code detection

Blocks used: IR input, Serial print
Block sequence:

Setup IR receiver
Detect button press
Print hex code

MicroPython Code:

import irremote, time                         # Import IR library and time

ir_rx = irremote.NEC_RX(26,8)                 # IR receiver on pin 26, buffer 8

while True:                                   # Infinite loop
    if ir_rx.any():                           # If any IR signal detected
        code = ir_rx.code[0]                  # Read first code
        print("IR code:", hex(code))          # Print hex code
    time.sleep(0.2)                           # Delay for stability

Reflection: Remote button codes are detected and printed.
Challenge: Press different buttons and note their hex codes.

🎮 Microproject 2.1.2 – IR LED Control

Blocks used: IR input, Digital output, Logic
Block sequence:

Setup IR receiver + LED
If button “1” pressed → LED ON
If button “0” pressed → LED OFF

MicroPython Code:

import irremote, machine, time                # Import IR, machine, time

ir_rx = irremote.NEC_RX(26,8)                 # IR receiver setup
pin5 = machine.Pin(5, machine.Pin.OUT)        # LED on pin 5

while True:                                   # Infinite loop
    if ir_rx.any():                           # If IR signal detected
        code = ir_rx.code[0]                  # Read code
        print("Received:", hex(code))         # Serial log
        if code == 0x45:                      # Button "1" hex-command
            pin5.value(1)                     # LED ON
            print("LED ON")                   # Serial log
        elif code == 0x19:                    # Button "0" hex-command
            pin5.value(0)                     # LED OFF
            print("LED OFF")                  # Serial log
    time.sleep(0.2)                           # Delay

Reflection: LED responds to remote buttons.
Challenge: Add button “2” for blinking LED.

🎮 Microproject 2.1.3 – Remote ON/OFF

Blocks used: IR input, Logic, Toggle
Block sequence:

Setup IR receiver + LED
Button “OK” toggles LED state

MicroPython Code:

import irremote, machine, time                # Import modules

ir_rx = irremote.NEC_RX(26,8)                 # IR receiver
pin5 = machine.Pin(5, machine.Pin.OUT)        # LED output

state = 0                                     # LED state variable

while True:                                   # Infinite loop
    if ir_rx.any():                           # If IR signal detected
        code = ir_rx.code[0]                  # Read code
        print("Received:", hex(code))         # Serial log
        if code == 0x1c:                      # Button "OK"
            state = 1 - state                 # Toggle state
            pin5.value(state)                 # Apply state
            print("LED state:", state)        # Serial log
    time.sleep(0.2)                           # Delay

Reflection: LED toggles ON/OFF with “OK” button.
Challenge: Add “#” button to reset OFF.

🎮 Microproject 2.1.4 – Control of multiple LEDs

Blocks used: IR input, Digital outputs, Logic
Block sequence:

Setup IR receiver + 2 LEDs
Button “2” → LED1 ON
Button “3” → LED2 ON

MicroPython Code:

import irremote, machine, time                # Import modules

ir_rx = irremote.NEC_RX(26,8)                 # IR receiver
pin5 = machine.Pin(5, machine.Pin.OUT)        # LED1 output
pin4 = machine.Pin(4, machine.Pin.OUT)        # LED2 output

while True:                                   # Infinite loop
    if ir_rx.any():                           # If IR signal detected
        code = ir_rx.code[0]                  # Read code
        print("Received:", hex(code))         # Serial log
        if code == 0x46:                      # Button "2"
            pin5.value(1)                     # LED1 ON
            print("LED1 ON")
        elif code == 0x47:                    # Button "3"
            pin4.value(1)                     # LED2 ON
            print("LED2 ON")
        elif code == 0x19:                    # Button "0"
            pin5.value(0); pin4.value(0)      # Both OFF
            print("LEDs OFF")
    time.sleep(0.2)                           # Delay

Reflection: Multiple LEDs controlled by remote.
Challenge: Add button “4” to turn both ON.

🎮 Microproject 2.1.5 – IR Macro Commands

Blocks used: IR input, Logic, Sequence
Block sequence:

Setup IR receiver + LED
Button “Up” triggers sequence

MicroPython Code:

import irremote, machine, time                # Import modules

ir_rx = irremote.NEC_RX(26,8)                 # IR receiver
pin5 = machine.Pin(5, machine.Pin.OUT)        # LED output

while True:                                   # Infinite loop
    if ir_rx.any():                           # If IR signal detected
        code = ir_rx.code[0]                  # Read code
        print("Received:", hex(code))         # Serial log
        if code == 0x18:                      # Button "Up"
            print("Macro sequence start")     # Serial log
            pin5.value(1); time.sleep(1)      # LED ON 1s
            pin5.value(0); time.sleep(1)      # LED OFF 1s
            pin5.value(1); time.sleep(2)      # LED ON 2s
            pin5.value(0)                     # LED OFF
            print("Macro sequence end")       # Serial log
    time.sleep(0.2)                           # Delay

Reflection: Remote triggers macro sequence.
Challenge: Add button “Down” for reverse sequence.

✨ Main Project – IR Remote Control

🔧 Blocks Steps (with glossary)

IR input: Detect button codes.
Logic: Map codes to actions.
Digital outputs: LEDs respond to remote.
Macro: Sequences triggered by special buttons.

Block sequence:

Setup IR receiver.
Setup LEDs.
Detect button codes.
Control LEDs ON/OFF.
Add macro sequence.

🐍 MicroPython Code (mirroring blocks)

# Project 2.1 – IR Remote Control

import irremote, machine, time                # Import IR, machine, time

# Setup IR receiver
ir_rx = irremote.NEC_RX(26,8)                 # IR receiver on pin 26, buffer 8

# Setup LEDs
pin5 = machine.Pin(5, machine.Pin.OUT)        # LED1 on pin 5
pin4 = machine.Pin(4, machine.Pin.OUT)        # LED2 on pin 4

# State variables
led1_state = 0                                # LED1 initial state OFF
led2_state = 0                                # LED2 initial state OFF

while True:                                   # Infinite loop
    if ir_rx.any():                           # If IR signal detected
        code = ir_rx.code[0]                  # Read first code
        print("Received:", hex(code))         # Serial log

        # Button "1" → LED1 ON
        if code == 0x45:                      # Hex-command for button 1
            pin5.value(1)                     # LED1 ON
            led1_state = 1
            print("LED1 ON")

        # Button "2" → LED2 ON
        elif code == 0x46:                    # Hex-command for button 2
            pin4.value(1)                     # LED2 ON
            led2_state = 1
            print("LED2 ON")

        # Button "0" → All OFF
        elif code == 0x19:                    # Hex-command for button 0
            pin5.value(0); pin4.value(0)      # Both LEDs OFF
            led1_state = 0; led2_state = 0
            print("LEDs OFF")

        # Button "OK" → Toggle LED1
        elif code == 0x1c:                    # Hex-command for OK
            led1_state = 1 - led1_state       # Toggle state
            pin5.value(led1_state)            # Apply state
            print("LED1 toggled:", led1_state)

        # Button "Up" → Macro sequence
        elif code == 0x18:                    # Hex-command for Up
            print("Macro sequence start")
            pin5.value(1); time.sleep(1)      # LED1 ON 1s
            pin5.value(0); time.sleep(1)      # LED1 OFF 1s
            pin4.value(1); time.sleep(2)      # LED2 ON 2s
            pin4.value(0)                     # LED2 OFF
            print("Macro sequence end")

    time.sleep(0.2)                           # Delay for stability

📖 External Explanation

This project shows how to use an IR remote to control LEDs.

Button codes are detected with the IR receiver.
Hex commands map each button to an action.
Logic decides ON/OFF, toggle, or macro sequence.
Outputs (LEDs) respond to remote control.

✨ Story Time

Imagine your robot as a smart TV 📺. Each button on the remote becomes a command: turn lights ON, toggle them OFF, or run a special sequence. With IR, you are the director of your robot’s show.

🕵️ Debugging (2 Common Problems)

🐞 Debugging 2.1.A – No IR signal detected

Problem: Remote button press not detected.
Clues: Wrong pin or buffer size.
Broken code:

ir_rx = irremote.NEC_RX(21,4)   # Wrong pin and buffer

Fixed code:

ir_rx = irremote.NEC_RX(26,8)   # Correct pin and buffer

Why it works: Correct wiring and buffer ensure detection.

🐞 Debugging 2.1.B – Incorrect codes

Problem: Button press shows wrong hex code.
Clues: Using raw codes instead of hex-command.
Broken code:

if code == 0xba45ff00:   # Raw code

Fixed code:

if code == 0x45:         # Hex-command

Why it works: Hex-command is simpler and consistent.

✅ Final Checklist

IR receiver setup correct.
Button codes detected.
LED ON/OFF control works.
Toggle logic implemented.
Macro sequence programmed.

📚 Extras

🧠 Student tip: Try mapping buttons to different devices.
🧑‍🏫 Instructor tip: Show raw vs hex codes to explain simplification.
📖 Glossary: IR, hex-command, toggle, macro.
💡 Mini tip: Always test with print(hex(code)) before mapping actions.