Home Automation Using Raspberry Pi Pico & Bluetooth module

In this tutorial, we will learn how to build a Home Automation Using Raspberry Pi Pico & Bluetooth module with MicroPython Code. Control your electronic appliances with your smartphone.

Bluetooth-controlled home automation technology allows users to control remotely different devices in their homes such as lighting, air conditioning, and security systems. using Bluetooth-enabled devices like a smartphone, tablets, or laptops.

The Bluetooth module receives signals from the smartphone and transmits data to the microcontroller.

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Requires Material

Raspberry Pi Pico
4- Channel Relay module
Jumper wires
AC load (such as light bulbs or fans)

Collect the all required hardware components.

HC-05 Bluetooth module

The HC-05 is a popular Bluetooth module that can be used for wireless transmission between microcontrollers It has a range of up to 10 meters with UART communication protocols. One of the most common uses for the HC-05 module is in home automation systems where it can be used to control lights, fans, and other appliances using a smartphone.

HC-05 Bluetooth module can be easily connected to microcontrollers such as Arduino and ESP8266/ESP32. check out the Interfacing HC-05 Bluetooth Module With Raspberry Pi Pico

HC-05 Bluetooth module Pinout

The HC-05 Bluetooth module has a 6-pin for attaching to a microcontroller. Here is the pinout diagram for the HC-05 module:

HC-05 Pin Description

EN: Enable pin
VCC: Power supply voltage (3.6V to 6V)
GND: Ground
RXD: Receive data pin
TXD: Transmit data pin
STATE: Status pin

Note: STATE and EN pins are optional they are not required for basic communication with the microcontroller.

Features of HC-05 Bluetooth module

Bluetooth version: Bluetooth 2.0 + EDR (Enhanced Data Rate)
Frequency band: 2.4GHz ISM band
Sensitivity: -80dBm
Communication Range: up to 10 meters
UART interface: 9600 bps
Power supply voltage: 3.6V – 6V DC
Operating current: <30mA
Operating temperature: –20°C to +75°C
Dimensions: 27mm x 13mm x 2.2mm

HC 05 Module is easy to combine with microcontrollers and other devices and is generally used in home automation, robotics, and DIY projects.

Wiring Diagram – Home Automation Using Raspberry Pi Pico

Here is a wiring diagram for a home automation system using Raspberry Pi Pico & HC 05 Bluetooth module

You can also follow my mapping

HC -05 Module	RASPBERRY PI PICO
VCC	3.3V
GND	GND
RX	GP0
TX	GP1

Relay –> Raspberry Pi ico

VCC –> 5V
GND –> GND
IN1=> GP16
IN2 => GP17
IN3=> GP18
IN4 => GP19
COM terminal => Supply from mains
NO terminal => Supply line to bulb

Recommended reading: Getting Started Raspberry Pi Pico – Pinout, Specs

Connect the Devices

Since we are using a four-channel relay module & we will be controlling two bulbs.

Bluetooth App configure

Serial Bluetooth Terminal is an Android application that allows you to communicate with a Microcontroller like a Raspberry pi pico board with Bluetooth. With this app, you can send and receive data from your Pico board wirelessly. Download Serial Bluetooth Terminal

Here is the step to use the Serial Bluetooth Terminal

To connect to the Pico for the first time, you need to Pair your Android device with a Bluetooth module.
Go to Devices.

Open the Bluetooth Serial Monitor app. On the menu bar, connect Bluetooth Devices:

Send and receive data from the pico board using the Serial Bluetooth Terminal app.

Micropython Code – Home Automation Using Raspberry Pi Pico & Bluetooth

After assembling the circuit, copy the following sketch to your Thonny IDE.

copy the below code and save it in the Pico board as the “main.py” name.

from machine import Pin
from machine import UART
from time import sleep
        HC05=UART(0,9600)

relay_1=Pin(16,Pin.OUT)

relay_2=Pin(17,Pin.OUT)

relay_3=Pin(18,Pin.OUT)

relay_4=Pin(19,Pin.OUT)

while True:
    if HC05.any()>0:
        data=HC05.read(1)
        
        if "a" in data:     
              relay_1.on()  
                             
        if "b" in data:
                       relay_1.off()
                            

        if "c" in data:
                       relay_2.on()
                           

        if "d" in data:
                      relay_2.off()
                              

        if "e" in data:
                            relay_3.on()

        if "f" in data:
                    relay_3.off()

        if "g" in data:
                      relay_4.on()
        if "h" in data:
                 relay_4.off()

from machine import Pin

from machine import UART

from time import sleep

HC05=UART(0,9600)

relay_1=Pin(16,Pin.OUT)

relay_2=Pin(17,Pin.OUT)

relay_3=Pin(18,Pin.OUT)

relay_4=Pin(19,Pin.OUT)

while True:

if HC05.any()>0:

data=HC05.read(1)

if "a" in data:

relay_1.on()

if "b" in data:

relay_1.off()

if "c" in data:

relay_2.on()

if "d" in data:

relay_2.off()

if "e" in data:

relay_3.on()

if "f" in data:

relay_3.off()

if "g" in data:

relay_4.on()

if "h" in data:

relay_4.off()

Testing the Project

You can write the following commands.

“a” and “b” messages to control the first Relay.
“c” and “d” messages to control the second Relay.
“e” and “f” messages to control the third Relay.
“g” and “h” messages to control the fourth Relay.

The application has several controls which means you can save default messages. For example, you can associate M1 with the “a” message, and M2 with the “b” message.