6.2 Electronic Thermometer
==============================
Build your own **smart weather station** that displays real-time temperature and humidity on a beautiful LCD screen! This is like having a professional weather monitor right on your desk.

**Why is this cool?** Instead of just reading numbers in the serial monitor, you'll create a **standalone device** with its own display that anyone can read at a glance. Perfect for monitoring your room comfort, greenhouse conditions, or just impressing friends with your own weather station!

**What makes it special:** This project combines two powerful sensors - the DHT11 for precise temperature and humidity readings, plus an LCD display that makes your data visible to everyone. It's like upgrading from a basic thermometer to a digital weather display!

**Project Features:**
- 📊 **Real-time monitoring**: Updates temperature and humidity every 2 seconds
- 🖥️ **Clear LCD display**: No need for a computer - readings shown directly on screen
- 🌡️ **Dual sensor data**: Both temperature (°C) and humidity (%) in one device
- 🔄 **Auto-refresh**: Display automatically updates with latest readings
- ⚡ **Error handling**: Shows helpful messages if sensor has issues

**How it works:**
The DHT11 sensor measures both temperature and humidity from the air around it, then sends this data digitally to your Pico. The LCD screen displays this information in an easy-to-read format, creating a professional-looking weather station!

Component List
^^^^^^^^^^^^^^^
- Raspberry Pi Pico W x1
- MicroUSB cable x1
- 830 Tie-Points Breadboard x1
- LCD1602 IIC x1
- DHT11 Module x1
- Jumper Wire Several

Connect
^^^^^^^^^
.. image:: img/3.connect/6.2.png

Code
^^^^^^^
.. note::

    * Open the ``6.2_electronic_thermometer.py`` file under the path of ``Ultimate-Starter-Kit-for-Pico-W\1.Project`` or copy this code into Thonny, then click "Run Current Script" or simply press F5 to run it.

    * Don't forget to click on the "MicroPython (Raspberry Pi Pico)" interpreter in the bottom right corner. 

.. 6.2.png

After running the code, watch your **personal weather station** come to life! Here's what you'll see:

**🔄 What happens when you run it:**
1. **Initial startup**: The system initializes the DHT11 sensor and LCD display
2. **First reading**: Within 2 seconds, you'll see the current temperature and humidity appear on the LCD
3. **Continuous updates**: Every 2 seconds, the display refreshes with new readings
4. **Smart formatting**: Temperature shows in Celsius (°C) and humidity as a percentage (%)

**📱 Your LCD will show something like:**
```
Temp: 23.5C
Humi: 45.2%
```

**🧪 Fun experiments to try:**
- **Breathe on the sensor** - watch humidity jump up instantly!
- **Hold an ice cube near it** - see temperature drop
- **Move it to different rooms** - compare temperature variations
- **Cover it with your hand** - observe both temperature and humidity changes

**💡 Troubleshooting:**
If you see "Sensor Error" on the display, don't worry! The system will automatically retry reading the sensor. This sometimes happens with DHT11 sensors and usually resolves within a few seconds.

The following is the program code:

.. code-block:: python

    from lcd1602 import LCD
    from machine import I2C, Pin
    import utime as time
    from dht import DHT11, InvalidPulseCount

    # Initialize DHT11 and LCD
    sensor = DHT11(Pin(16, Pin.IN, Pin.PULL_UP))  # Connect DHT11 to GPIO16
    i2c = I2C(1, sda=Pin(6), scl=Pin(7), freq=400000)
    lcd = LCD(i2c)

    def read_sensor():
        """Read data from the DHT11 sensor"""
        try:
            sensor.measure()
            temp = sensor.temperature
            hum = sensor.humidity
            return temp, hum
        except InvalidPulseCount:
            print('Invalid pulse count - retrying...')
            return None, None
        except Exception as e:
            print('Error reading sensor:', e)
            return None, None

    # Main loop
    while True:
        temp, hum = read_sensor()
        if temp is not None and hum is not None:
            # Display temperature and humidity
            string = "Temp: {:.1f}C\nHumi: {:.1f}%".format(temp, hum)
            lcd.message(string)
        else:
            lcd.message("Sensor Error\nPlease wait...")

        time.sleep(2)  # DHT11 recommends a sampling interval of at least 2 seconds
        lcd.clear()

Phenomenon
^^^^^^^^^^^
.. video:: img/5.phenomenon/6.2.mp4
    :width: 100%