Raspberry Pi information display small screen, display time, IP address, CPU information, memory information (C language), four-wire i2c communication, 0.96-inch oled screen

0、前提：Raspberry Pi already haswiringPithis package andcmake,If no, please go（wiringPi参考链接）（cmake参考链接）参考链接自己安装

1、Connect the wires and turn on the Raspberry Pii2c

1.1、接线

Four wires usedoled gnd vcc scl sdaJust connect it

Specific wiring diagram as follows：

1.2、打开i2c

输入命令 sudo raspi-config,选择第3item start5项的i2c

 

2、Download what I wroteoled驱动代码GitHub链接：GitHub - ShangHTao/Raspberry-sysinfo-display: 树莓派i2cinterface driven0.96寸的oled显示屏,可以显示ip地址cpuOccupancy and temperature etc.

2.1For example, we first enter the desktop and perform the following operations

cd ~/Desktop
mkdir test
cd test/
git clone https://github.com/ShangHTao/Raspberry-sysinfo-display

This creates atestinside the folderoled显示程序

2.2构建代码,执行下面的操作

cd Raspberry-sysinfo-display/
ls

enter the commandCMakeCache.txtfile deletion abilitycmake

输入命令

rm CMakeCache.txt 
cmake .
make

 如图所示,constructed aoled_i2c_show_status的可执行程序

可以简单使用./oled_i2c_show_status执行一下看看oledWhether the corresponding content is displayed

It is recommended to run input commands in the background ./oled_i2c_show_status & （多加一个&）

3、设置开机自启动

问题1：在 /etc/rc.d/rc.local添加sudo nohup ~/oled_i2c_show_status &It will start automatically,But after a while the quest is killed it's not worth it why,Can someone please explain.

问题2：在~/.config文件中创建的autostart.desktopSet the boot to start automatically is also runningsudo nohup ~/oled_i2c_show_status &,Also back kills after running for a while,Does anyone with a good heart know?？

ps：直接运行sudo nohup ~/oled_i2c_show_status &Can always run without being killed,为什么？

思考：我创建个shell脚本,然后开机自启动,在shell里面执行sudo nohup ~/oled_i2c_show_status &Is it possible not to be killed?？

I know how to prevent system kill command and update again,Format and nothing to be adjusted later,There are still many errors,望指正.......（The above content is for Xiaobai to learnlinux的记录,It is a small white,欢迎大家交流,Students who need the original code can browse and make suggestions）

        All of the above problems have been found,is due to the loop callpopen()function but error段错误,I can't solve it after looking for many reasons.

        后面又使用fopen()Functions may indeed increase the background time to run,但是还是错误（报错too many open files,But obviously it has been usedfclose()function still error）,very annoying.怀疑是fopen()It's a standard library function after all.,Then switch to system functionopen()依然报错too many open files,The clock reaches a certain level and kills the background.

Finally built ashell脚本（我起名为）Check if you have been killed,Execute again if killed,Otherwise, continue to check,具体内容如下：

#!/bin/sh
while :
do
    if [ $(ps -ef | grep -c "oled_i2c_show_status") -lt 2 ]; 
    then
    $( /home/pi/autostart/oled_i2c_show_status  &) ; 
    fi
    sleep 60s
done

Indeed, it continued to execute when it was killed.oled_i2c_show_status,But sensory indicators don't cure the root cause.I'll try it later, if it workspython里的os.popen(),python调用c库函数.

4、python设计

​​​​​​​等待更新....