功率/等级
“on”表示设备应该被恢复并且不自动挂起
允许。（当然，仍然允许系统挂起。）
“auto”是允许内核运行的正常状态
自动挂起和自动恢复设备。
“挂起”表示设备应保持挂起状态，并且
不允许自动恢复。 （但可能仍然允许远程唤醒，
因为它是由 power/wakeup 属性单独控制的。）
第 1 步： 所以我有，usb1、usb2、usb3、usb4 ....
$ cat /sys/bus/usb/devices/usb*/power/level
auto
auto
auto
auto
第 2 步： 我怎么知道哪个是哪个？ (
# echo "on" | tee /sys/bus/usb/devices/usb*/power/level
# cat /sys/bus/usb/devices/usb*/power/level
on
on
on
on
Optional 1: 万一 lsusb 显示，需要找到特定的
#!/bin/bash
usb="046d:082d" # Find ME, Replace the ID
cam=$(lsusb | awk "/$usb/ {print $6}")
echo $cam
if [ ! -z "$cam" -a "$cam" != " " ]; then
for X in /sys/bus/usb/devices/*;
do
a=$(cat "$X/idVendor" 2>/dev/null)
b=$(cat "$X/idProduct" 2>/dev/null)
c="$a:$b"
if [ ! -z "$c" -a "$c" != " " ] && [ "$c" == "$usb" ]; then
d=$(echo $X | sed "s/\/sys\/bus\/usb\/devices\///g")
echo "[FOUND] $d"
#sudo sh -c "echo on > /sys/bus/usb/devices/$d/authorized"
sleep 2
#sudo sh -c "echo on > /sys/bus/usb/devices/$d/authorized"
lsusb
break
fi
done;
fi
可选 2： 万一没有找到 - 重新启动无法重新启动，使用 Arduino 中继而不是 udp
#!/bin/bash
file="/var/www/html/video/now.jpeg"
function age() {
local filename=$1
local changed=`stat -c %Y "$filename"`
local now=`date +%s`
local elapsed
let elapsed=now-changed
echo $elapsed
}
while true
do
target="/dev/video99"
foundon="none"
warn="[WARNING]:"
ok="[OK]:"
for i in 0 1 2 3 4
do
tmp="/dev/video$i"
if [ -e $tmp ]; then
foundon="/dev/video$i"
#else
# echo "no $i"
fi
done
b="none"
if [ "$foundon" = "$b" ]; then
echo "$warn No camera is found - inform reboot or arduino boot"
else
echo "$ok ln -s $foundon $target"
### Camera is available but something is not correct so ###
file_age=$(age "$file")
echo The age of $file is $file_age seconds.
if [[ ! -f $file ]]; then
echo "file is not found. Kernel sucks for 500mA USB's"
else
echo "found file: $file_age"
if [[ $file_age -gt 240 ]]; then
echo "$warn greater then 240 seconds"
else
echo "$ok - less then 240 seconds"
fi
fi
fi
ls /dev/video*
sleep 5
done
Arduino 继电器：
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
byte mac[]={0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xAD};
IPAddress ip(10,109,4,166);
byte gateway[]= {10,109, 0, 1};
byte subnet[]= {255, 255, 248,0};
unsigned int localPort = 8888;
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
char ReplyBuffer[] = "ackv1";
EthernetUDP Udp;
int led1 = 2;
int led2 = 3;
void setup() {
Ethernet.begin(mac,ip);
//Ethernet.begin(mac, ip, '8.8.8.8', gateway, subnet);
Udp.begin(localPort);
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
}
void loop() {
int packetSize = Udp.parsePacket();
if(packetSize) {
delay(1000);
digitalWrite(led1, HIGH); // turn the LED off by making the voltage LOW
delay(3000);
digitalWrite(led1, LOW); // turn the LED on (HIGH is the voltage level)
delay(1000);
digitalWrite(led2, HIGH); // turn the LED off by making the voltage LOW
delay(3000);
digitalWrite(led2, LOW); // turn the LED on (HIGH is the voltage level)
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}
delay(10);
}