🌱 MicroPython SHT11 Temperature & Humidity Sensor

This project demonstrates how to interface the SHT11 sensor with a MicroPython-compatible ESP32 board (e.g., Lolin32 Lite) to measure temperature and relative humidity. It uses bit-banged communication and is written fully in MicroPython.

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📁 Project Structure

MicroPython-SHT11
├── LICENSE                    # License file (e.g., MIT)
├── README.md                  # This documentation
└── project/
    ├── main.py                # Main script to read and display sensor values
    └── sht11.py               # SHT11 driver implementation in MicroPython

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📦 Requirements

• ⚙️ MicroPython board: Tested on Lolin32 Lite (ESP32)

• 🌡️ Sensor: Sensirion SHT11 (Digital Temp & RH sensor)

• 🧠 Firmware: MicroPython 1.20 or later

• 🧰 Development tools:

  • Thonny IDE or mpremote
  • USB to Serial connection

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🔌 Wiring

SHT11 Pin	Description	ESP32 Pin (Example)
1 (SCK)	Clock	GPIO 26
2 (DATA)	Data	GPIO 33
3 (GND)	Ground	GND
4 (VCC)	Power (3.3V)	3.3V

⚠️ Note: Do not power SHT11 with 5V — it's a 3.3V device.

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🧪 Example Usage

In the main.py:

# example code to read SHT11 using MicroPython
# author : Ardy Seto P
# email  : [email protected]
# board  : Lolin32 Lite (ESP32)

from sht11 import SHT11

# Define SCK and DATA GPIO pins
sht = SHT11(sck=26, data=33)

# Read temperature and humidity
tempOut = sht.temperature()
humOut = sht.humidity()

# Display results
print('Temperature: ', tempOut, '*C')
print('Humidity: ', humOut, '%')

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🔧 Features of the SHT11 Driver

• 📡 Pure MicroPython bit-banged protocol (no I2C)

• 📊 Reads:

  • Temperature (°C)
  • Relative Humidity (%RH)

• ✅ Includes:

  • CRC check
  • Command protocol implementation
  • Adjustable temperature compensation for RH

Key Methods

SHT11(sck, data)         # Initialize driver with SCK and DATA pins
.temperature()           # Return temperature in °C
.humidity(temp=25)       # Return relative humidity (%), with temp compensation
.read_register()         # Read status register (raw access)

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⚙️ Advanced Notes

• This driver replicates the SHT11 protocol using direct GPIO pin manipulation.
• Built-in CRC-8 validation helps detect communication errors.
• The .humidity() method includes temperature compensation if called with custom temperature values.

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💡 Troubleshooting

• ❌ CRC or ACK errors: Make sure your wires are short and well-connected. SHT11 is sensitive to interference.
• 🔁 Slow reads? SHT11 has ~200–300 ms measurement latency; this is normal.
• 📉 Values look wrong? Double-check power source and resistor pull-up configuration (if needed).

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📜 License

This project is open-source under the MIT License.

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👤 Author

Ardy Seto Priambodo ✉️ [email protected]