Raspberry Pi

Thursday. March 29, 2018 - 3 mins

Computer RPi

1-Wire Bus

实验中使用的传感器是DS18B20，不能接反否则会迅速发热烫手甚至烧坏器件；
使用1-wire总线需要先进入 raspi-config ，在 interfacing options 里面enable 1-wire（SSH、SPI、I2C、VNC等都采用同样的方式设置，都可利用lsmod检查）；
利用 lsmod 检查 w1-gpio 模块和 w1-therm 模块是否存在，若没有则：

sudo modprobe w1-gpio

sudo modprobe w1-therm
进入 /sys/bus/w1/devices 目录，可以看到文件夹 w1_bus_master1 和 28-* ， cat 28-*/w1_slave 可以读到温度数据；
如果 ls 没有任何结果，则可能是内核版本问题，需要修改 /boot/config.txt 文件，在末尾添加：

dtoverlay=w1-gpio-pullup, gpioin=4

DATE: 2018-03-29

树莓派中文环境配置

参考文献：http://shumeipai.nxez.com/2016/03/13/how-to-make-raspberry-pi-display-chinese.html

scim中文输入法：

安装中文字体：

sudo apt-get install ttf-wqy-zenhei
安装中文输入法：

sudo apt-get install scim-pinyin
修改树莓派配置：

sudo raspi-config

在change_locale中选择zh_CN.UTF-8
重启后即可

DATE: 2018-03-30

参考文献：http://shumeipai.nxez.com/2015/03/11/raspberry-pi-to-install-chinese-input-method-fcitx-and-google-pinyin-ime.html

另一种安装fcitx输入法及google拼音支持的方法（现在自己都是用的这种方法，沉迷google不能自拔…）

安装fcitx输入法：

sudo apt-get install fcitx
下载google拼音支持：

sudo apt-get install fcitx-googlepinyin

修改用户密码

参考文献：https://blog.csdn.net/guanmaoming/article/details/78760428

修改pi用户密码

sudo passwd pi
修改root用户密码

sudo passwd root
用户切换

su root

su pi

修改镜像源

参考文献：https://blog.csdn.net/la9998372/article/details/77886806

使用管理员权限编辑/etc/apt/sources.list文件：

sudo vim /etc/apt/sources.list

#注释掉原来的内容，写入以下内容：

deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi
deb-src http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi

使用管理员权限编辑/etc/apt/sources.list.d/raspi.list文件：

sudo vim /etc/apt/sources.list.d/raspi.list

#注释掉原来的内容，写入以下内容：

deb http://mirror.tuna.tsinghua.edu.cn/raspberrypi/ stretch main ui
deb-src http://mirror.tuna.tsinghua.edu.cn/raspberrypi/ stretch main ui

更新软件源列表：

sudo apt-get update

需要安装的包

vim
lftp
curl
ctags

DATE: 2018-05-22

python包安装：pip install [package]

python帮助文档：pydoc [package]

RPi.GPIO

参考文献：RPi.GPIO的wiki：https://sourceforge.net/p/raspberry-gpio-python/wiki/Home/

图片来源：RPi.Pinout：https://blog.csdn.net/coder9999/article/details/76904625

Demo Code

Instructions List

([] means it depends on your settings, / means those are options, {} means it is optional)
GPIO.setmode([mode])
GPIO.getmode()
GPIO.setwarnings(False)
GPIO.setup([channel/chan_list], GPIO.IN/GPIO.OUT, {initial=GPIO.HIGH})
GPIO.input([channel])
GPIO.output([channel/chan_list], [state])
GPIO.cleanup(), GPIO.cleanup([channel/chan_list])
GPIO.RPI_INFO, GPIO.VERSION() (refer to wiki)

Importing the module

# To import the RPi.GPIO module:
import RPi.GPIO as GPIO

# To import the module and check to see if it is successful:
try:
    import RPi.GPIO as GPIO
except RuntimeError:
    print("Error importing RPi.GPIO!  This is probably because you need superuser privileges.  You can achieve this by using 'sudo' to run your script")

Pin numbering

# To set the numbering system:
GPIO.setmode(GPIO.BOARD)
GPIO.setmode(GPIO.BCM)

# To detect the numbering system:
mode = GPIO.getmode()

RPi_pinout

If you are confused about the numbers of these systems, you can use gpio readall in terminal to show it like this:

GPIO_readall

Warnings

# To disable warnings while more than one script/circuit on the GPIO of RPi:
GPIO.setwarnings(False)

Setup channel(s)

# [channel] depends on the numbering system you choose
	
# To configure a channel as an input:
GPIO.setup([channel], GPIO.IN)

# To set up a channel as an output:
GPIO.setup([channel], GPIO.OUT)
	
# Specify an initial value of output channel:
GPIO.setup([channel], GPIO.OUT, initial=GPIO.HIGH)
	
# Set up more than one channel per call:
chan_list = [11, 12]  # You can tuples instead
GPIO.setup(chan_list, GPIO.OUT)

Input & Output

# To read the value of a GPIO pin:
GPIO.input([channel])

# TO set the output state of a GPIO pin:
GPIO.output([channel], [state])

# State can be 0/GPIO.LOW/False or 1/GPIO.HIGH/True

# Output to several channels
chan_list = [11, 12]
GPIO.output(chan_list, GPIO.LOW)  # Set all to GPIO.LOW
GPIO.output(chan_list, (GPIO.HIGH, GPIO.LOW))  # Set first HIGH and second LOW

Cleanup

# It is good practice to clean up any resources you might have used. By returning all channels you have used back to inputs with no pull up/down, you can avoid accidental damage to your RPi by shorting out the pins. Note that this will only clean up GPIO channels that your script has used. Note that GPIO.cleanup() also clears the pin numbering system in use.
# To clean up channels you used at the end of script:
GPIO.cleanup()

# Clean up individual channels, a list or a tuple of channels:
GPIO.cleanup([channel])
GPIO.cleanup((channel1, channel2))
GPIO.cleanup([channel1, channel2])

Kaixin Yang

做你该做的事情，并接受它的事与愿违