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作者：@jf_07365693

樹莓派RP2350 - 桌面動態(tài)溫濕度計

本文介紹了DFrobotBeetle RP2350 開發(fā)板結合 DHT11 模塊、鋰電池模塊、隨機眨眼動畫，實現(xiàn) OLED 顯示的桌面動態(tài)溫濕度計的項目設計。

一、項目介紹

本項目包括

工作原理：ADC 電壓采集與電量轉換

工程調試：電量獲取、電量圖標顯示、DHT11 溫濕度顯示、OLED 眨眼動畫

工程代碼：合并調試代碼，實現(xiàn)完整的項目設計功能

效果演示：幀動畫顯示、動態(tài)展示

最終實現(xiàn)桌面動態(tài)溫濕度計的制作。

工作原理

根據(jù)開發(fā)板原理圖可知，電池 VBAT 的分壓電路與主控的 GPIO29 模擬接口相連，因此通過該引腳可實時采集監(jiān)測電池電壓信息，進而實現(xiàn)電量顯示。

二、硬件連接

GP0 -> DATA (DHT11)

GP4 -> SDA (OLED)

GP5 -> SCL (OLED)

BAT -> Battery Positive

GND -> Battery Negative

示意圖

三、工程調試

包括 ADC 電量采集、電量的 OLED 顯示、DHT11溫濕度數(shù)據(jù)和電量圖標的顯示、眨眼動畫等調試項目。

1. 電量獲取

通過 ADC 讀取 GPIO29 電壓值并終端打印

代碼

from machine import Pin, ADC
import utime

# initialize ADC pin
adc = ADC(Pin(29))

# parameters for voltage divide resistor
R1, R2 = 1000000, 1000000
DIV_RATIO = (R1 + R2) / R1

def get_battery_level():
adc_value = adc.read_u16()
voltage = (adc_value / 65535) * 3.3
actual_voltage = voltage * DIV_RATIO # voltage division compensation
percent = min(max((actual_voltage - 3.3) / (4.2 - 3.3) * 100, 0), 100)
return percent, actual_voltage

while True:
percent, voltage = get_battery_level()
print('Battery Voltage: {:.2f} V, Battery Level: {:.1f}%'.format(voltage,percent))
utime.sleep(1)

保存代碼，連接開發(fā)板，配置解釋器并運行。

效果

終端打印 ADC 采集的電池電壓值以及電量百分比

2. 電量顯示

OLED 顯示 ADC 采集的電量百分比。

代碼

from machine import Pin, ADC, I2C
import ssd1306
import utime

# initialize ADC pin
adc = ADC(Pin(29))

# initialize OLED
i2c = I2C(0, scl=Pin(5), sda=Pin(4))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# parameters of voltage divide resistor
R1, R2 = 1000000, 1000000 # 1M
Vref_BAT = 3.9 # battery voltage in full charged state

def get_battery_level():
adc_value = adc.read_u16()
voltage = (adc_value / 65535) * 3.3
DIV_RATIO = (R1 + R2) / R1
actual_voltage = voltage * DIV_RATIO # voltage division compensation
percent = min(max((actual_voltage - 3.3) / (Vref_BAT - 3.3) * 100, 0), 100)
return percent, actual_voltage

def draw_battery(percent):
oled.fill(0)
oled.text('{:.0f}%'.format(percent), 0, 17)
# draw battery cartoon icon
oled.rect(0, 0, 30, 15, 1) # frame (x,y,width,height)
oled.rect(30, 5, 3, 5, 1) # anode
oled.fill_rect(2, 2, int(26 * percent / 100), 11, 1) # electric percent column
oled.rotate(0)
oled.show()

def BAT_display(percent,x,y): # battery percent, icon position (x,y)
oled.fill(0)
oled.text('{:.0f}%'.format(percent), 0+x, 17+y)
# draw battery cartoon icon
oled.rect(0+x, 0+y, 30, 15, 1) # frame (x,y,width,height)
oled.rect(30+x, 5+y, 3, 5, 1) # anode
oled.fill_rect(2+x, 2+y, int(26 * percent / 100), 11, 1) # electric percent column
oled.rotate(0)
oled.show()

def draw_vertical_battery(percent,x,y): # battery percent, icon position (x,y)
oled.fill(0)
oled.text('{:.0f}'.format(percent), 0+x, 33+y)
# draw battery cartoon icon
oled.rect(0+x, 2+y, 15, 30, 1) # frame (x,y,width,height)
oled.rect(5+x, 0+y, 5, 3, 1) # anode
fill_h = int(27 * percent / 100)
oled.fill_rect(2+x, 2 + (28 - fill_h) + y, 11, fill_h, 1) # percent column
oled.rotate(0)
oled.show()

while True:
percent, voltage = get_battery_level()
#draw_battery(percent)
BAT_display(percent,90,2)
#draw_vertical_battery(percent,90,9)
print('Battery Voltage: {:.2f} V, Battery Level: {:.1f}%'.format(voltage,percent))
utime.sleep(2)

保存代碼，連接開發(fā)板，配置解釋器并運行。

效果

電量圖標的水平顯示

電量圖標的豎直顯示

3. DHT11 溫濕度計

帶電量顯示的 DHT11 溫濕度計

代碼

from machine import Pin, ADC, I2C
from PicoDHT22 import PicoDHT22
import ssd1306
import utime

# initialize ADC pin
adc = ADC(Pin(29))

# initialize OLED
i2c = I2C(0, scl=Pin(5), sda=Pin(4))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# parameters of voltage divide resistor
R1, R2 = 1000000, 1000000
Vref_BAT = 3.81 # battery voltage in full charged state

def get_battery_level():
adc_value = adc.read_u16()
voltage = (adc_value / 65535) * 3.3
DIV_RATIO = (R1 + R2) / R1
actual_voltage = voltage * DIV_RATIO # voltage division compensation
percent = min(max((actual_voltage - 3.3) / (Vref_BAT - 3.3) * 100, 0), 100)
return percent, actual_voltage

def draw_battery(percent):
oled.fill(0)
oled.text('{:.0f}%'.format(percent), 90, 27)
# draw battery cartoon icon
oled.rect(90, 10, 30, 15, 1) # frame
oled.rect(120, 15, 3, 5, 1) # anode
oled.fill_rect(92, 12, int(26 * percent / 100), 11, 1) # electric percent column
oled.show()

def BAT_display(percent):
oled.fill(0)
oled.text('{:.0f}%'.format(percent), 90, 27)
# draw battery cartoon icon
oled.rect(90, 10, 30, 15, 1) # frame
oled.rect(120, 15, 3, 5, 1) # anode
oled.fill_rect(92, 12, int(26 * percent / 100), 11, 1)
oled.show()

def draw_vertical_battery(percent,x,y):
# 局部清屏并顯示電量百分比
oled.fill_rect(x,y,15+8,30+16,0)
oled.text('{:.0f}'.format(percent), 0+x, 33+y)
# 豎版電池繪制
oled.rect(0+x, 2+y, 15, 30, 1) # frame (x,y,width,height)
oled.rect(5+x, 0+y, 5, 3, 1) # anode
fill_h = int(26 * percent / 100)
oled.fill_rect(2+x, 2 + (28 - fill_h) + y, 11, fill_h, 1) # percent column
oled.rotate(0)
oled.show()

def display_TH(temp,humi):
oled.fill_rect(20,15,6*8,64-15,0) # 局部清屏
oled.text("Temperature:", 0, 0)
oled.text("{:.1f} C".format(temp), 20, 15)
oled.text("Humidity:", 0, 35)
oled.text("{:.1f} %".format(humi), 20, 50)
oled.rotate(0) # rotate the screen display for a more comfortable position
oled.show()

dht_sensor=PicoDHT22(Pin(0,Pin.IN,Pin.PULL_UP),dht11=True)
while True:
temp,humi = dht_sensor.read()
percent, voltage = get_battery_level()
#draw_battery(percent)
#BAT_display(percent)
draw_vertical_battery(percent,90,16)
display_TH(temp,humi)
print('Battery Voltage: {:.2f} V, Battery Level: {:.1f}%'.format(voltage,percent))
utime.sleep(2)

效果

電量和溫濕度顯示，數(shù)據(jù)刷新的時間間隔為 2 秒

4. 眨眼動畫

OLED 顯示矩形填充狀眼睛，改變形狀并利用人眼的視覺暫留效應實現(xiàn)眨眼效果。

代碼

from machine import Pin, I2C
import ssd1306
import utime
import urandom

i2c = I2C(0, scl=Pin(5), sda=Pin(4))
oled_width = 128
oled_height = 64
oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)

def draw_eyes(state,xshift,yshift):
"""state: 0=完全睜開, 1=半閉, 2=完全閉上"""
width,height = (int)(oled_width/5),(int)(oled_height/3)
cx,cy = (int)((oled_width-2.5*width)/2),(int)((oled_height-height)/2) # eyes at scrren center 定位點為矩形左上角
x = cx + xshift
y = cy + yshift
oled.fill_rect(x, y, int(2.5*width), height, 0)
# draw left eye
if state == 0: # 完全睜開
oled.fill_rect(x, y, width, height, 1)
elif state == 1: # 半閉
oled.fill_rect(x, y+(int)(height/4), width, (int)(height/2), 1)
else: # 完全閉上
oled.hline(x, y+(int)(height/2), width, 1)
# draw right eye
if state == 0: # 完全睜開
oled.fill_rect(x+width+(int)(width/2), y, width, height, 1)
elif state == 1: # 半閉
oled.fill_rect(x+width+(int)(width/2), y+(int)(height/4), width, (int)(height/2), 1)
else: # 完全閉上
oled.hline(x+width+(int)(width/2), y+(int)(height/2), width, 1)
oled.show()

def blink_eyes(xshift,yshift):
# 睜眼狀態(tài)保持
draw_eyes(0,xshift,yshift)
utime.sleep(1)
# 眨眼動畫序列
draw_eyes(1,xshift,yshift) # 半閉
utime.sleep(0.1)
draw_eyes(2,xshift,yshift) # 全閉
utime.sleep(0.1)
draw_eyes(1,xshift,yshift) # 半閉
utime.sleep(0.1)
draw_eyes(0,xshift,yshift) # 全開

def random_eyes():
xshift = urandom.randint(-(int)(oled_width/4),(int)(oled_width/4))
yshift = urandom.randint(-(int)(oled_height/3),(int)(oled_height/3))
oled.fill(0)
blink_eyes(xshift,yshift)
#print(xshift,yshift)

while True:
random_eyes()
#blink_eyes(0,0)

保存代碼，連接開發(fā)板，配置解釋器并運行。

效果

眨眼效果（眼睛位置在屏幕內隨機移動）

四、工程代碼

將工程調試的代碼合并，實現(xiàn)溫濕度數(shù)據(jù)（包括電池電量）與息屏隨機眨眼動畫的切換顯示。

from machine import Pin, ADC, I2C
from PicoDHT22 import PicoDHT22
import ssd1306
import utime
import urandom

# initialize ADC pin
adc = ADC(Pin(29))

# initialize OLED
i2c = I2C(0, scl=Pin(5), sda=Pin(4))
oled_width = 128
oled_height = 64
oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)

# parameters of voltage divide resistor
R1, R2 = 1000000, 1000000
Vref_BAT = 3.81 # battery voltage in full charged state

def get_battery_level():
adc_value = adc.read_u16()
voltage = (adc_value / 65535) * 3.3
DIV_RATIO = (R1 + R2) / R1
actual_voltage = voltage * DIV_RATIO # voltage division compensation
percent = min(max((actual_voltage - 3.3) / (Vref_BAT - 3.3) * 100, 0), 100)
return percent, actual_voltage

def draw_vertical_battery(percent,x,y):
# 局部清屏并顯示電量百分比
oled.fill_rect(x,y,15+8,30+16,0)
oled.text('{:.0f}'.format(percent), 0+x, 33+y)
# 豎版電池繪制
oled.rect(0+x, 2+y, 15, 30, 1) # frame (x,y,width,height)
oled.rect(5+x, 0+y, 5, 3, 1) # anode
fill_h = int(26 * percent / 100)
oled.fill_rect(2+x, 2 + (28 - fill_h) + y, 11, fill_h, 1) # percent column
oled.rotate(0)
oled.show()

def display_TH(temp,humi):
oled.fill_rect(20,15,6*8,64-15,0) # part clear
oled.text("Temperature:", 0, 0)
oled.text("{:.1f} C".format(temp), 20, 15)
oled.text("Humidity:", 0, 35)
oled.text("{:.1f} %".format(humi), 20, 50)
oled.rotate(0) # rotate the screen display for a more comfortable position
oled.show()

def draw_eyes(state,xshift,yshift):
"""state: 0=full open, 1=half open, 2=close"""
width,height = (int)(oled_width/5),(int)(oled_height/3)
cx,cy = (int)((oled_width-2.5*width)/2),(int)((oled_height-height)/2) # eyes at scrren center
x = cx + xshift
y = cy + yshift
oled.fill_rect(x, y, int(2.5*width), height, 0)
# draw left eye
if state == 0: # full open
oled.fill_rect(x, y, width, height, 1)
elif state == 1: # half open
oled.fill_rect(x, y+(int)(height/4), width, (int)(height/2), 1)
else: # close
oled.hline(x, y+(int)(height/2), width, 1)
# draw right eye
if state == 0: # full open
oled.fill_rect(x+width+(int)(width/2), y, width, height, 1)
elif state == 1: # half open
oled.fill_rect(x+width+(int)(width/2), y+(int)(height/4), width, (int)(height/2), 1)
else: # close
oled.hline(x+width+(int)(width/2), y+(int)(height/2), width, 1)
oled.show()

def blink_eyes(xshift,yshift):
# keep opening
draw_eyes(0,xshift,yshift)
utime.sleep(0.5)
# blink eyes order
draw_eyes(1,xshift,yshift) # half open
utime.sleep(0.1)
draw_eyes(2,xshift,yshift) # close
utime.sleep(0.1)
draw_eyes(1,xshift,yshift) # half open
utime.sleep(0.1)
draw_eyes(0,xshift,yshift) # full open
utime.sleep(0.5)

def random_eyes():
xshift = urandom.randint(-(int)(oled_width/4),(int)(oled_width/4))
yshift = urandom.randint(-(int)(oled_height/3),(int)(oled_height/3))
oled.fill(0)
blink_eyes(xshift,yshift)
#print(xshift,yshift)

dht_sensor = PicoDHT22(Pin(0,Pin.IN,Pin.PULL_UP),dht11=True)
def TH_BAT():
''' temperature and humidity and battery '''
temp,humi = dht_sensor.read()
percent, voltage = get_battery_level()
oled.fill(0)
display_TH(temp,humi)
draw_vertical_battery(percent,90,16)
print('Temperature: {:.2f} C, Humidity: {:.2f} RH, Battery Voltage: {:.2f} V, Battery Level: {:.1f}%'.format(temp,humi,voltage,percent))
utime.sleep(2)

while True:
TH_BAT()
random_eyes()

連接開發(fā)板，配置解釋器，將代碼保存至根目錄，取下數(shù)據(jù)線，連接電池，實現(xiàn)顯示效果。

五、最終效果展示

幀動畫分別如下

六、項目總結

本文介紹了樹莓派 RP2350 開發(fā)板結合 DHT11 模塊、鋰電池模塊、隨機眨眼動畫，實現(xiàn) OLED 顯示的桌面動態(tài)溫濕度計的項目設計。通過多任務結合，為更多 DIY 設計提供了可能，如添加按鍵掃描或語音控制模塊，實現(xiàn)指定的功能切換與人機交互，拓展和豐富了該開發(fā)板在物聯(lián)網(wǎng)領域的創(chuàng)新與應用，為 RP2350 的開發(fā)設計和產(chǎn)品應用提供了參考。