「第37回シェル芸勉強会 大阪サテライト LT」( https://speakerdeck.com/mikkun/shell-script-for-raspberry-pi )で紹介したシェルスクリプト

rpi-pir-alarm

#!/bin/bash --

# Name    : rpi-pir-alarm
# Purpose : Motion Detection and Email Notification Using Raspberry Pi
#
# Author  : KUSANAGI Mitsuhisa <[email protected]>
# License : MIT License

# Usage : ./rpi-pir-alarm

#=============================================================================
# Initialization
#=============================================================================
#-----------------------------------------------------------------------------
# Define variable(s)
#-----------------------------------------------------------------------------
set -u
shopt -s expand_aliases

if [ "$(uname)" != 'Linux' ] ; then
    alias awk='gawk'
    alias date='gdate'
    alias fold='gfold'
    alias sed='gsed'
    alias tac='tail -r'
    alias tr='gtr'
fi

PATH='/usr/bin:/bin'
export PATH

GPIO=17
INTERVAL=0.5
WAIT=30

IMG_DIR='/tmp'
MAX_IMGS=50

FROM='[email protected]'
TO='[email protected]'

#-----------------------------------------------------------------------------
# Define function(s)
#-----------------------------------------------------------------------------
remove_gpio() {
    echo "Removing GPIO #${GPIO}..." >&2
    echo $GPIO > '/sys/class/gpio/unexport'
    sleep $INTERVAL

    echo "Stopped ${0##*/}." >&2
    exit 0
}

#-----------------------------------------------------------------------------
# Setup GPIO
#-----------------------------------------------------------------------------
set -e

if [ -d "/sys/class/gpio/gpio${GPIO}" ] ; then
    echo "Resetting GPIO #${GPIO}..." >&2
    echo $GPIO > '/sys/class/gpio/unexport'
    sleep $INTERVAL
fi

echo "Exporting GPIO #${GPIO}..." >&2
echo $GPIO > '/sys/class/gpio/export'
sleep $INTERVAL

echo "Setting the direction of GPIO #${GPIO}..." >&2
echo 'in' > "/sys/class/gpio/gpio${GPIO}/direction"
sleep $INTERVAL

trap remove_gpio SIGINT SIGTERM

#=============================================================================
# Main
#=============================================================================
set +e

echo "Started ${0##*/}." >&2

prev_value=0
curr_value=0

while : ; do
    curr_value=$(cat "/sys/class/gpio/gpio${GPIO}/value" || echo 0)

    if [ "$curr_value" -gt $prev_value ] ; then
        date=$(date '+%s')
        file="${IMG_DIR}/${0##*/}_$(date -d "@${date}" '+%Y%m%d%H%M%S').jpg"

        raspistill -w 640 -h 480 -o "$file" -ev 7

        cat << END_MAIL | /usr/lib/sendmail -t
From: $FROM
To: $TO
Subject: ${0##*/}: [$(date -d "@${date}" '+%F %T')]
MIME-Version: 1.0
Content-type: multipart/mixed; boundary="${date}_$$"
Content-Transfer-Encoding: 7bit

--${date}_$$
Content-Type: $(file -bi "$file" | sed 's/; charset=binary//'); name="${file##*/}"
Content-Disposition: attachment; filename="${file##*/}"
Content-Transfer-Encoding: base64

$(base64 "$file")
--${date}_$$--
END_MAIL

        if [ "$MAX_IMGS" -gt 0 ] ; then
            find "$IMG_DIR" -maxdepth 1 -name "${0##*/}_*" |
            sort -r                                        |
            sed "1,${MAX_IMGS}d"                           |
            tr '\n' '\0'                                   |
            xargs -0 rm -f
        fi

        sleep $WAIT
    fi

    prev_value=$curr_value
    sleep $INTERVAL
done