树莓派学习笔记（四）——温湿度检测（本地OLED显示、ONENET云平台显示）

前言

用树莓派4b做一个温湿度检测仪，温湿度传感器模块SHT20收集温湿度数据，在OLED SSD1306上显示，同时把数据上传到onenet平台用网页显示。

所需材料：树莓派；SHT20温湿度传感器 ；Oled屏幕 ssd1306/1106；杜邦线；面包板

本文所出现的代码均在我的码云上，地址：temperater程序

[2020.6.11]

一、硬件连接

SHT20和SSD1306和树莓派之间使用I2C总线通信方式，引脚连接如下：

GND---GND
VCC---3.3V
SCL---SCL
SDA---SDA

SHT20:

SSD1306:

树莓派引脚图：

---

二、树莓派开启I2C功能

参考1：SHT20温湿度采集

参考2：I2C接口的OLED在树莓派上的应用

1、使能I2C Kernel Module

远程登陆树莓派后，输入sudo raspi-config 后，选择5.Interfacing Options 选择P5 I2C 选择 是，如下图所示：

2、安装I2C-Tools

sudo apt-get install i2c-tools
sudo apt-get install python-smbus
sudo adduser pi i2c
sudo reboot

安装完成后输入i2cdetect -y 1，检查各个模块的地址

图中0x40是SHT20地址， 0x30是OLED屏幕的地址

---

三、本地温度显示

1、安装luma.oled的包

sudo apt-get install libfreetype6-dev libjpeg-dev build-essentia
sudo apt-get install python3-dev python3-pip
sudo -H pip3 install --upgrade luma.oled

注：目前已经不支持python3以下的版本更新了

2、点亮oled屏幕

运行oled2.py（python3运行）python3 oled2.py

# oled2.py
from luma.core.interface.serial import i2c, spi
from luma.core.render import canvas
from luma.oled.device import ssd1306, ssd1325, ssd1331, sh1106
import time
import socket
import fcntl
import struct

serial = i2c(port=1, address=0x3C)
oled = ssd1306(serial)


def getIP(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(fcntl.ioctl(
        s.fileno(),
        0x8915,  # SIOCGIFADDR
        struct.pack('256s', ifname[:15].encode('utf-8'))
    )[20:24])


def oledIP():
    with canvas(oled) as draw:
        draw.text((2, 5), "IP: " + getIP("wlan0") + '\n' + "I'm working\nbut no people", fill=255)


def oledinit():
    serial = i2c(port=1, address=0x3C)
    oled = ssd1306(serial)


def oleddisplay(In, x, y):
    with canvas(oled) as draw:
        # draw.rectangle(device.bounding_box, outline="white", fill="black")
        draw.text((x, y), In, fill="white")

'''
if __name__ == "__main__":
    oledinit()
    # oledIP()
    In = "hello "
    oleddisplay(In, 15, 20)
    '''
oledinit()
while (1):

    oledIP()
    #In = "hello "
    oleddisplay(In, 15, 20)
    time.sleep(3)

显示效果：

3、本地温湿度检测

运行temp_local.py（python2.7运行）python temp_local

代码如下：

# temp_local.py
import smbus
import time

F8X16=										    \
(										    \
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,\
  0x00,0x00,0x00,0xF8,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x33,0x30,0x00,0x00,0x00,\
  0x00,0x10,0x0C,0x06,0x10,0x0C,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,\
  0x40,0xC0,0x78,0x40,0xC0,0x78,0x40,0x00,0x04,0x3F,0x04,0x04,0x3F,0x04,0x04,0x00,\
  0x00,0x70,0x88,0xFC,0x08,0x30,0x00,0x00,0x00,0x18,0x20,0xFF,0x21,0x1E,0x00,0x00,\
  0xF0,0x08,0xF0,0x00,0xE0,0x18,0x00,0x00,0x00,0x21,0x1C,0x03,0x1E,0x21,0x1E,0x00,\
  0x00,0xF0,0x08,0x88,0x70,0x00,0x00,0x00,0x1E,0x21,0x23,0x24,0x19,0x27,0x21,0x10,\
  0x10,0x16,0x0E,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,\
  0x00,0x00,0x00,0xE0,0x18,0x04,0x02,0x00,0x00,0x00,0x00,0x07,0x18,0x20,0x40,0x00,\
  0x00,0x02,0x04,0x18,0xE0,0x00,0x00,0x00,0x00,0x40,0x20,0x18,0x07,0x00,0x00,0x00,\
  0x40,0x40,0x80,0xF0,0x80,0x40,0x40,0x00,0x02,0x02,0x01,0x0F,0x01,0x02,0x02,0x00,\
  0x00,0x00,0x00,0xF0,0x00,0x00,0x00,0x00,0x01,0x01,0x01,0x1F,0x01,0x01,0x01,0x00,\
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0xB0,0x70,0x00,0x00,0x00,0x00,0x00,\
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x01,\
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x30,0x30,0x00,0x00,0x00,0x00,0x00,\
  0x00,0x00,0x00,0x00,0x80,0x60,0x18,0x04,0x00,0x60,0x18,0x06,0x01,0x00,0x00,0x00,\
  0x00,0xE0,0x10,0x08,0x08,0x10,0xE0,0x00,0x00,0x0F,0x10,0x20,0x20,0x10,0x0F,0x00,\
  0x00,0x10,0x10,0xF8,0x00,0x00,0x00,0x00,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,\
  0x00,0x70,0x08,0x08,0x08,0x88,0x70,0x00,0x00,0x30,0x28,0x24,0x22,0x21,0x30,0x00,\
  0x00,0x30,0x08,0x88,0x88,0x48,0x30,0x00,0x00,0x18,0x20,0x20,0x20,0x11,0x0E,0x00,\
  0x00,0x00,0xC0,0x20,0x10,0xF8,0x00,0x00,0x00,0x07,0x04,0x24,0x24,0x3F,0x24,0x00,\
  0x00,0xF8,0x08,0x88,0x88,0x08,0x08,0x00,0x00,0x19,0x21,0x20,0x20,0x11,0x0E,0x00,\
  0x00,0xE0,0x10,0x88,0x88,0x18,