Circuit Documentation

Summary

This circuit is designed to interface with various sensors and actuators through a Raspberry Pi Pico W microcontroller. It includes environmental sensing through a DHT11 temperature and humidity sensor, light level sensing with a photocell (LDR), and motion detection using an RCWL-0516 microwave radar sensor. The circuit can control a two-channel relay to switch external devices like a bulb and a fan. It also features pushbuttons for user input. The Raspberry Pi Pico W is programmed to operate in either an app mode with Wi-Fi and MQTT communication or an automatic mode that reacts to sensor inputs.

Component List

Raspberry Pi Pico W

• Microcontroller board with Wi-Fi capabilities.
• Provides GPIO pins for interfacing with sensors and actuators.

DHT11

• Temperature and humidity sensor.
• Outputs digital signal with environmental data.

Two Channel Relay 5V

• Relay module with two channels.
• Allows for controlling high power devices like a bulb and a fan.

Photocell (LDR)

• Light-dependent resistor.
• Changes resistance based on the ambient light level.

Resistor (10k Ohms)

• Three resistors with a resistance of 10k Ohms.
• Used for pull-up/pull-down configurations or as part of a voltage divider.

RCWL-0516 Microwave Radar Motion Sensor Module

• Motion detection sensor using microwave radar technology.
• Outputs digital signal upon detecting motion.

Pushbutton

• Two simple pushbuttons for user input.
• Can be used to change modes or trigger events.

BULB

• A generic bulb that can be switched on or off.
• Connected to the relay for control by the microcontroller.

Power Supply

• Provides power to the circuit.
• Outputs a stable voltage for the components.

Fan

• An electric fan that can be switched on or off.
• Connected to the relay for control by the microcontroller.

Wiring Details

Raspberry Pi Pico W

• VSYS connected to Relay VCC.
• GP16 connected to RCWL-0516 OUT.
• GND connected to common grounds.
• GP26 connected to one side of the LDR and a 10k Ohm resistor.
• 3V3 OUT connected to LDR, DHT11, and RCWL-0516 3V3.
• GP4 connected to DHT11 out.
• GP6 connected to Relay IN1.
• GP7 connected to Relay IN2.
• GP8 and GP9 connected to pushbuttons through 10k Ohm resistors.

DHT11

• + connected to 3V3 OUT from Raspberry Pi Pico W.
• out connected to GP4 on Raspberry Pi Pico W.
• - connected to GND.

Two Channel Relay 5V

• VCC connected to VSYS on Raspberry Pi Pico W.
• IN1 and IN2 connected to GP6 and GP7 on Raspberry Pi Pico W.
• GND connected to common ground.
• NC1 and NC2 connected to BULB and Fan respectively.
• C1 and C2 connected to Power Supply +.

Photocell (LDR)

• One side connected to 3V3 OUT from Raspberry Pi Pico W.
• Other side connected to GP26 on Raspberry Pi Pico W and a 10k Ohm resistor.

Resistor (10k Ohms)

• Three resistors used, each connected between a signal line and ground or 3V3 OUT.

RCWL-0516 Microwave Radar Motion Sensor Module

• OUT connected to GP16 on Raspberry Pi Pico W.
• GND connected to common ground.
• 3V3 connected to 3V3 OUT from Raspberry Pi Pico W.

Pushbutton

• One side of each button connected to GP8 and GP9 on Raspberry Pi Pico W through a 10k Ohm resistor.
• Other side connected to GND.

BULB

• + connected to NC1 on Relay.
• - connected to Power Supply -.

Power Supply

• + connected to C1 and C2 on Relay.
• - connected to common ground, BULB -, and Fan GND.

Fan

• 5V connected to NC2 on Relay.
• GND connected to Power Supply -.

Documented Code

import machine
import network
import time
import dht
from machine import Pin
from machine import I2C
from lcd_api import LcdApi
from i2c_lcd import I2cLcd
from time import sleep
import utime
from umqtt.simple import MQTTClient

SSID = "project"
PASSWORD = "12345678"
MQTT_BROKER = "test.mosquitto.org"
MQTT_TOPIC = "JN_17102024"

# Set up the DHT11 sensor
dht_pin = machine.Pin(4)  # Change this to the GPIO pin you connected the DHT11 data pin to
dht_sensor = dht.DHT11(dht_pin)
degree_celsius_symbol = chr(223)

ldr_pin = machine.ADC(26)  # LDR sensor (light detection)
microwave_sensor = machine.Pin(16, machine.Pin.IN)
light = machine.Pin(6, machine.Pin.OUT)  # LED 1
fan = machine.Pin(7, machine.Pin.OUT)  # LED 2
button1 = machine.Pin(8, machine.Pin.IN)
button2 = machine.Pin(9, machine.Pin.IN)
light.value(1)
fan.value(1)
current_mode = None

I2C_ADDR = 0x27
totalRows = 2
totalColumns = 16
sensor = dht.DHT11(Pin(6))

i2c = I2C(1, sda=machine.Pin(2), scl=machine.Pin(3), freq=400000)
lcd = I2cLcd(i2c, I2C_ADDR, totalRows, totalColumns)

lcd.clear()
lcd.putstr("     WELCOME      ")
lcd.move_to(0,1)
lcd.putstr("________________")
time.sleep(1)
lcd.clear()
lcd.putstr("SELECT MODE")
time.sleep(1)

def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        print('Connecting to Wi-Fi...')
        lcd.clear()
        lcd.putstr("CONNECTING")
        lcd.move_to(0,1)
        lcd.putstr("WIFI....")
        time.sleep(2)
        wlan.connect(SSID, PASSWORD)
        while not wlan.isconnected():
            time.sleep(1)
    print('Connected to Wi-Fi:', wlan.ifconfig())
    lcd.clear()
    lcd.putstr("WIFI")
    lcd.move_to(0,1)
    lcd.putstr("CONNECTED")
    time.sleep(2)

# Function to handle MQTT messages
def mqtt_callback(topic, msg):
    print((topic, msg))
    
    # Check message and control LED
    if msg == b'a':
        light.value(0)
    elif msg == b'b':
        light.value(1)
    elif msg == b'c':
        fan.value(0)
    elif msg == b'd':
        fan.value(1)

# Connect to the MQTT broker and subscribe to the topic
def connect_mqtt():
    client = MQTTClient('raspberry_pi_pico', MQTT_BROKER)
    lcd.clear()
    lcd.putstr("MQTT")
    lcd.move_to(0,1)
    lcd.putstr("CONNECTING..")
    time.sleep(2)
    client.set_callback(mqtt_callback)
    client.connect()
    client.subscribe(MQTT_TOPIC)
    print(f"Subscribed to topic {MQTT_TOPIC}")
    lcd.clear()
    lcd.putstr("MQTT")
    lcd.move_to(0,1)
    lcd.putstr("CONNECTED")
    time.sleep(2)
    
    while True:
        client.check_msg()  # Continuously check for incoming messages
        time.sleep(1)
        if button2.value() == 0:
            break

def sensor_control():
    while True:
        movement_detected = microwave_sensor.value()
        dht_sensor.measure()
        temperature_c = dht_sensor.temperature()
        temperature_string = f'{temperature_c}{degree_celsius_symbol}C'
        humidity = dht_sensor.humidity()
        print(movement_detected)
        if movement_detected == 1:
            lcd.clear()
            lcd.putstr("MOVEMENT")
            lcd.putstr(" DET")
            time.sleep(2)
            for i in range(60, 0, -1):   # Reverse loop from 100 to 1
                if i>=40:
                    fan.value(0)
                lcd.clear()
                lcd.putstr("Time:")
                lcd.putstr(str(i))  # Countdown
                lcd.putstr(" SECS")
                lcd.move_to(0,1)
                lcd.putstr("T:")
                lcd.putstr(str(temperature_string))
                lcd.putstr(" H:")
                lcd.putstr(str(humidity))
                lcd.putstr("%")
                time.sleep(1)
                light_value = ldr_pin.read_u16()
                if light_value <= 10000:
                    light.value(0)
                if light_value >= 20000