Learn Python and develop smart home control systems

In today's era of intelligent technology, smart home systems are becoming standard equipment in people's daily lives, from smart door locks and smart light bulbs to smart speakers, smart home appliances, etc., smart home It is gradually infiltrating into our lives. As a programming language that has become more popular in recent years, Python has become the preferred development language for many smart home control systems because of its rapid development, easy learning, and powerful functions.

So, this article will introduce how to use Python and Raspberry Pi to develop a simple smart home control system, and provide corresponding code examples.

1. Raspberry Pi preparation

The Raspberry Pi is a microcomputer based on the Linux operating system. It can be used as the core component of many projects, including our smartphone Home systems. Before starting development, please make sure you already have a Raspberry Pi and have successfully installed the python environment and some necessary libraries.

On the Raspberry Pi, we can control connected electronic components through the GPIO port. The GPIO port is the abbreviation of General Purpose Input and Output Port. It can provide general digital input/output functions through which we can control LED lights, motors, sensors and other components.

2. Use Python for control

For controlling LED lights, motors and other components, we can use the RPi.GPIO library in Python. This library will give some constants, methods or mechanisms related to GPIO for us to use. During the learning process, one method that will often be used is "output IO port", which refers to using a program to control the GPIO port to output a high level. or low potential.

The following is a simple LED light control example:

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)               # 设置GPIO口的编码方式为BCM编码方式
GPIO.setup(18, GPIO.OUT)             # 将GPIO18设置为输出口
 

try:
    while True:
        GPIO.output(18, GPIO.HIGH)   # 打开LED灯
        time.sleep(1)                # 暂停1s，控制LED灯持续时间
        GPIO.output(18, GPIO.LOW)    # 关闭LED灯
        time.sleep(1)
except KeyboardInterrupt:
    GPIO.cleanup()                   # 释放GPIO口，清空资源

In the above code, GPIO.BCM sets the encoding method of the GPIO port to the BCM encoding method. GPIO.setup(18, GPIO.OUT) sets GPIO18 port as an output port. In the following while loop, we use the GPIO.output() method to control the LED light on and off. When the value is GPIO.HIGH, it means turning on the LED light. When the value is GPIO.LOW, it means turning off the LED light.

3. Control multiple components

For controlling multiple components, we can use a method similar to the above, and only need to assign a GPIO port to each component. For example, the following code demonstrates how to control two LED lights:

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)                         # 设置GPIO口的编码方式为BCM编码方式
GPIO.setup(18, GPIO.OUT)                       # 设置GPIO18为输出口
GPIO.setup(23, GPIO.OUT)                       # 设置GPIO23为输出口
 

try:
    while True:
        GPIO.output(18, GPIO.HIGH)             # 打开LED1
        GPIO.output(23, GPIO.LOW)              # 关闭LED2
        time.sleep(1)                          # 暂停1s
        GPIO.output(18, GPIO.LOW)              # 关闭LED1
        GPIO.output(23, GPIO.HIGH)             # 打开LED2
        time.sleep(1)                          # 暂停1s
except KeyboardInterrupt:
    GPIO.cleanup()                             # 释放GPIO口，清空资源

We can assign a GPIO port to each component, for example, LED1 is assigned GPIO18 port, and LED2 is assigned GPIO23 port. Turning on or off the LED component is controlled using the GPIO.output() method.

4. Use sensor control

In smart home systems, sensors play a vital role. They can sense parameters in the environment, such as temperature, humidity, and light. , infrared, etc., so as to make corresponding actions through our program. For Python control sensors, we can use task scheduling libraries such as django-celery-beat and APScheduler for control.

Taking the temperature sensor as an example, we can use D1 mini to connect to wlan, connect to the MQTT server, and obtain sensor data. The following is a simple sample code:

import paho.mqtt.client as mqtt
import json

SERVER = "test.mosquitto.org"
PORT = 1883
TOPIC = "/v1.0/devices/6c49f6b29348c22333ad97f5b8a9c7e68a48f87a/sensors/temperature"
 
def on_connect(client, userdata, flags, rc):
    print("Connected with result code "+str(rc))
    client.subscribe(TOPIC)

def on_message(client, userdata, msg):
    data = json.loads(msg.payload.decode())
    if 'temperature' in data:
        print('温度传感器: ', data['temperature'])

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect(SERVER, PORT, 60)

client.loop_forever()

In the above code, we use the paho.mqtt.client library to connect to the MQTT server and obtain sensor data. At the same time, in the on_message() function, we can write corresponding control logic for different sensor data, such as controlling air conditioners, water heaters and other equipment to achieve smart home control purposes.

5. Summary

This article introduces how to use Python and Raspberry Pi to develop a simple smart home control system, and provides corresponding code examples. Of course, we are just scratching the surface, and we will still need to continue to learn, explore and practice in the future to build a complete smart home system.

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