树莓派 RP2350 - 桌面动态温湿度计

本文介绍了树莓派 RP2350 开发板结合 DHT11 模块、锂电池模块、随机眨眼动画，实现 OLED 显示的桌面动态温湿度计的项目设计。

扩展板及 3D 外壳详见：Beetle-RP2350扩展板 - 立创开源硬件平台 .

项目介绍

本项目包括 BMP280 传感器模块介绍、工作原理、参数特点等信息，在此基础上实现工程代码编写、硬件测试等流程，最终实现气压计的制作。

工作原理

根据开发板原理图可知，电池 VBAT 的分压电路与主控的 GPIO29 模拟接口相连，因此通过该引脚可实时采集监测电池电压信息，进而实现电量显示。

引脚功能定义详见：Pico-Series-Pinout .

分压计算参考：ADC 采样与分压电阻 .

硬件连接

• GP0 -> DATA (DHT11)
• GP4 -> SDA (OLED)
• GP5 -> SCL (OLED)
• BAT -> Battery Positive
• GND -> Battery Negative

示意图

工程调试

包括 ADC 电量采集、电量的 OLED 显示、DHT11温湿度数据和电量图标的显示、眨眼动画等调试项目。

电量获取

通过 ADC 读取 GPIO29 电压值并终端打印

代码

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)

保存代码，连接开发板，配置解释器并运行。

效果

终端打印 ADC 采集的电池电压值以及电量百分比

电量显示

OLED 显示 ADC 采集的电量百分比。

代码

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)

保存代码，连接开发板，配置解释器并运行。

效果

电量图标的水平显示

电量图标的竖直显示

DHT11 温湿度计

带电量显示的 DHT11 温湿度计

代码

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):
    # 局部清屏并显示电量百分比
    oled.fill_rect(x,y,15+8,30+16,0)
    oled.text('{:.0f}'.format(percent), 0+x, 33+y)
    # 竖版电池绘制
    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

电量和温湿度显示，数据刷新的时间间隔为 2 秒

眨眼动画

OLED 显示矩形填充状眼睛，改变形状并利用人眼的视觉暂留效应实现眨眼效果。

代码

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=完全睁开, 1=半闭, 2=完全闭上"""
    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 定位点为矩形左上角
    x = cx + xshift
    y = cy + yshift
    oled.fill_rect(x, y, int(2.5*width), height, 0)
    # draw left eye
    if state == 0:  # 完全睁开
        oled.fill_rect(x, y, width, height, 1)
    elif state == 1:  # 半闭
        oled.fill_rect(x, y+(int)(height/4), width, (int)(height/2), 1)
    else:  # 完全闭上
        oled.hline(x, y+(int)(height/2), width, 1)
    # draw right eye
    if state == 0:  # 完全睁开
        oled.fill_rect(x+width+(int)(width/2), y, width, height, 1)
    elif state == 1:  # 半闭
        oled.fill_rect(x+width+(int)(width/2), y+(int)(height/4), width, (int)(height/2), 1)
    else:  # 完全闭上
        oled.hline(x+width+(int)(width/2), y+(int)(height/2), width, 1)
    oled.show()
​
def blink_eyes(xshift,yshift):
    # 睁眼状态保持
    draw_eyes(0,xshift,yshift)
    utime.sleep(1)
    # 眨眼动画序列
    draw_eyes(1,xshift,yshift)  # 半闭
    utime.sleep(0.1)
    draw_eyes(2,xshift,yshift)  # 全闭
    utime.sleep(0.1)
    draw_eyes(1,xshift,yshift)  # 半闭
    utime.sleep(0.1)
    draw_eyes(0,xshift,yshift)  # 全开
​
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)

保存代码，连接开发板，配置解释器并运行。

效果

眨眼效果（眼睛位置在屏幕内随机移动）

工程代码

将工程调试的代码合并，实现温湿度数据（包括电池电量）与息屏随机眨眼动画的切换显示。

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):
    # 局部清屏并显示电量百分比
    oled.fill_rect(x,y,15+8,30+16,0)
    oled.text('{:.0f}'.format(percent), 0+x, 33+y)
    # 竖版电池绘制
    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()

连接开发板，配置解释器，将代码保存至根目录，取下数据线，连接电池，实现显示效果。

效果

帧动画分别如下

动态演示

总结

本文介绍了树莓派 RP2350 开发板结合 DHT11 模块、锂电池模块、随机眨眼动画，实现 OLED 显示的桌面动态温湿度计的项目设计。通过多任务结合，为更多 DIY 设计提供了可能，如添加按键扫描或语音控制模块，实现指定的功能切换与人机交互，拓展和丰富了该开发板在物联网领域的创新与应用，为 RP2350 的开发设计和产品应用提供了参考。