Acquire and display information from the temperature and humidity sensor DHT11 connected to Raspberry Pi Pico
https://raw.githubusercontent.com/d2r2/go-dht/master/docs/DHT11.pdf
Single bus usually require an external one is about 4.7 k Ω pull-up resistors, so that when the bus is idle, its status as a high level.
# This code is for reading temperature and humidity from a DHT11 sensor using MicroPython on an ESP8266 or ESP32 board.
# Make sure to install the DHT library for MicroPython if you haven't already.
import dht # Import the DHT sensor library
from machine import Pin # Import Pin class to control GPIO
import time # Import time module for delays
# Initialize the DHT11 sensor
# The DHT11 data pin is connected to GPIO6 (you can change this as needed)
dht11 = dht.DHT11(Pin(6))
# Continuously read and display temperature and humidity
while True:
try:
# Trigger the sensor to take a measurement
dht11.measure()
# Read temperature from the sensor (in degrees Celsius)
temp = dht11.temperature()
# Read humidity from the sensor (in percent)
hum = dht11.humidity()
# Display the readings in a formatted way
print(f"Temperature: {temp:.1f}*C") # e.g., "Temperature: 24.0°C"
print(f"Humidity : {hum:.1f}%") # e.g., "Humidity : 60.0%"
except Exception as e:
# If an error occurs (e.g., sensor not connected or checksum error), print error
print("Failed to read sensor:", e)
# Wait for 1 second before the next reading
time.sleep(1)
SSD1306 OLED (Organic Light-Emitting Diode) display module
# Import required libraries
import dht # Library for DHT11 temperature and humidity sensor
from machine import Pin, I2C # Pin and I2C classes from machine module for GPIO and I2C communication
import time # For adding delays between sensor readings
import ssd1306 # SSD1306 OLED display driver library
# Initialize the DHT11 sensor
# The data pin of DHT11 is connected to GPIO6 (GP6 on Raspberry Pi Pico)
dht11 = dht.DHT11(Pin(6))
# Initialize the I2C interface and SSD1306 OLED display
# The display is connected using I2C with:
# - SCL (clock line) on GPIO17 (GP17)
# - SDA (data line) on GPIO16 (GP16)
# The screen resolution is 128x64 pixels
i2c = I2C(scl=Pin(17), sda=Pin(16))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)
try:
# Start an infinite loop to repeatedly read data from the sensor and display it
while True:
try:
# Measure temperature and humidity using the DHT11 sensor
dht11.measure()
temp = dht11.temperature() # Temperature in Celsius
hum = dht11.humidity() # Humidity in percentage
# Clear the OLED display before showing new data
oled.fill(0)
# Display temperature and humidity on the OLED screen
oled.text(f"Temp : {temp:.1f}*C", 0, 0) # Display temperature at top-left
oled.text(f"Humi : {hum:.1f} %", 0, 16) # Display humidity below it
# Send the buffer to the display
oled.show()
# Also print the values to the serial console for debugging/logging
print(f"Temperature: {temp:.1f}*C")
print(f"Humidity : {hum:.1f} %")
except Exception as e:
# If reading the sensor fails (e.g., connection issue or checksum error)
# Print the error to the console and show error on the OLED
print("Failed to read sensor:", e)
oled.fill(0)
oled.text("Sensor Error!", 0, 0)
oled.show()
# Wait for 1 second before taking the next reading
time.sleep(1)
except KeyboardInterrupt:
# When script is manually stopped (e.g., Ctrl+C), clear the OLED
print("Script stopped by user. Clearing OLED display.")
oled.fill(0)
oled.show()SSD1306 OLED display driver
# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
import framebuf
# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xA4)
SET_NORM_INV = const(0xA6)
SET_DISP = const(0xAE)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xA0)
SET_MUX_RATIO = const(0xA8)
SET_IREF_SELECT = const(0xAD)
SET_COM_OUT_DIR = const(0xC0)
SET_DISP_OFFSET = const(0xD3)
SET_COM_PIN_CFG = const(0xDA)
SET_DISP_CLK_DIV = const(0xD5)
SET_PRECHARGE = const(0xD9)
SET_VCOM_DESEL = const(0xDB)
SET_CHARGE_PUMP = const(0x8D)
# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
def __init__(self, width, height, external_vcc):
self.width = width
self.height = height
self.external_vcc = external_vcc
self.pages = self.height // 8
self.buffer = bytearray(self.pages * self.width)
super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
self.init_display()
def init_display(self):
for cmd in (
SET_DISP, # display off
# address setting
SET_MEM_ADDR,
0x00, # horizontal
# resolution and layout
SET_DISP_START_LINE, # start at line 0
SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
SET_MUX_RATIO,
self.height - 1,
SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
SET_DISP_OFFSET,
0x00,
SET_COM_PIN_CFG,
0x02 if self.width > 2 * self.height else 0x12,
# timing and driving scheme
SET_DISP_CLK_DIV,
0x80,
SET_PRECHARGE,
0x22 if self.external_vcc else 0xF1,
SET_VCOM_DESEL,
0x30, # 0.83*Vcc
# display
SET_CONTRAST,
0xFF, # maximum
SET_ENTIRE_ON, # output follows RAM contents
SET_NORM_INV, # not inverted
SET_IREF_SELECT,
0x30, # enable internal IREF during display on
# charge pump
SET_CHARGE_PUMP,
0x10 if self.external_vcc else 0x14,
SET_DISP | 0x01, # display on
): # on
self.write_cmd(cmd)
self.fill(0)
self.show()
def poweroff(self):
self.write_cmd(SET_DISP)
def poweron(self):
self.write_cmd(SET_DISP | 0x01)
def contrast(self, contrast):
self.write_cmd(SET_CONTRAST)
self.write_cmd(contrast)
def invert(self, invert):
self.write_cmd(SET_NORM_INV | (invert & 1))
def rotate(self, rotate):
self.write_cmd(SET_COM_OUT_DIR | ((rotate & 1) << 3))
self.write_cmd(SET_SEG_REMAP | (rotate & 1))
def show(self):
x0 = 0
x1 = self.width - 1
if self.width != 128:
# narrow displays use centred columns
col_offset = (128 - self.width) // 2
x0 += col_offset
x1 += col_offset
self.write_cmd(SET_COL_ADDR)
self.write_cmd(x0)
self.write_cmd(x1)
self.write_cmd(SET_PAGE_ADDR)
self.write_cmd(0)
self.write_cmd(self.pages - 1)
self.write_data(self.buffer)
class SSD1306_I2C(SSD1306):
def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
self.i2c = i2c
self.addr = addr
self.temp = bytearray(2)
self.write_list = [b"\x40", None] # Co=0, D/C#=1
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.temp[0] = 0x80 # Co=1, D/C#=0
self.temp[1] = cmd
self.i2c.writeto(self.addr, self.temp)
def write_data(self, buf):
self.write_list[1] = buf
self.i2c.writevto(self.addr, self.write_list)
class SSD1306_SPI(SSD1306):
def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
self.rate = 10 * 1024 * 1024
dc.init(dc.OUT, value=0)
res.init(res.OUT, value=0)
cs.init(cs.OUT, value=1)
self.spi = spi
self.dc = dc
self.res = res
self.cs = cs
import time
self.res(1)
time.sleep_ms(1)
self.res(0)
time.sleep_ms(10)
self.res(1)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(0)
self.cs(0)
self.spi.write(bytearray([cmd]))
self.cs(1)
def write_data(self, buf):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(1)
self.cs(0)
self.spi.write(buf)
self.cs(1)
__version__ = '0.1.0'
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