Description

The principle of operation:

• The car drives up to the gates.

• Camera reads the car plate numbers.

• Checks the read number with the database; if it finds one, then it opens the gate and lets the car pass.

• Each car at the gates is photographed, then a photo is sent to the Telegram application with the car plate number and its status.

• Telegram bot has the ability to open and close the gates, take a current photo and add an unknown car to the database.

It's done with  Python + Bash + Telegram Bot.

Preparation

For this you will need an RPI3 with the Ubuntu Mate installed. You can get it here: https://ubuntu-mate.org/download/

Installing ALPR library

The easiest way to install

sudo apt-get update && sudo apt-get install -y openalpr openalpr-daemon openalpr-utils libopenalpr-dev

Install ImageMagick

sudo apt-get install imagemagick

Installing dependencies for Telegram bot

sudo apt-get install libreadline-dev libconfig-dev libssl-dev lua5.2 liblua5.2-dev libevent-dev libjansson-dev libpython-dev make 
apt-get update
apt-get -y install python-pip 
pip install pytelegrambotapi 
pip install json

Installing Telegram-cli

Check this link to install and configure telegram-cli in ubuntu.

Relay connection

• Connect relay to RPI 3. In my case I used GPIO23 pin for 1st relay and GPIO26 for the second one.

You can test the relay with shell script, just create a simple sh script and run it:

nano open.sh
chmod +x open.sh
sh open.sh

Paste the code below and run it.

Script code for relay 1:

#!/bin/bash 
echo 23 > /sys/class/gpio/export 
echo out > /sys/class/gpio/gpio23/direction 
echo 0 > /sys/class/gpio/gpio23/value 
ping -c 2 localhost 
echo 23 > /sys/class/gpio/export 
echo out > /sys/class/gpio/gpio23/direction 
echo 1 > /sys/class/gpio/gpio23/value

Script code for relay 2:

#!/bin/bash 
echo 26 > /sys/class/gpio/export 
echo out > /sys/class/gpio/gpio26/direction 
echo 0 > /sys/class/gpio/gpio26/value 
ping -c 2 localhost 
echo 26 > /sys/class/gpio/export 
echo out > /sys/class/gpio/gpio26/direction 
echo 1 > /sys/class/gpio/gpio26/value

Connect relays to gates

• Telegram message-send script

• Create .sh script with the following code:

#!/bin/bash 
 to=$1 
 msg=$2 
 tgpath=/home/user/tg 
 cd ${tgpath} 
 (sleep 1; echo "dialog_list";sleep 1; echo "msg $to $msg";) | ${tgpath}/bin/telegram-cli -k -W tg-server.pub 

Telegram photo-send script

• Create .sh script with the following code:

#!/bin/bash 
 to=$1 
 msg=$2 
 tgpath=/home/user/tg 
 cd ${tgpath} 
 (sleep 1; echo "dialog_list";sleep 1; echo "send_photo $to $msg";) | ${tgpath}/bin/telegram-cli -k -W tg-server.pub 

Create 2 files for the main recognition script:

touch log.txt
touch numbers.txt

In the numbers.txt - add all the known car plates numbers.

Order of the numbers.txt should be as follows:

YZO169

RFS961

RFS123

ILAI123

RFS872

Car plate recognition script

• 1st it connects to ip-camera and downloads a snapshot.

• then it renames the snapshot.cgi to .jpg file

• Next step is converting(zooming) the image. This step you should configure by yourself. In my case i used "crop 45%" because my camera was placed to high over the gates. So i needed to zoom the photo so the script could recognize the car plate.

• Rest i hope is clear.

#! /bin/bash 
wget -q http://login:password@ipadress/cgi-bin/snapshot.cgi -O /home/user/Downloads/autocheck/snapshot.cgi 
mv /home/user/Downloads/autocheck/snapshot.cgi /home/user/Downloads/autocheck/snapshot.jpg 
convert /home/user/Downloads/autocheck/snapshot.jpg -gravity Center -crop 45%\! /home/user/Downloads/autocheck/output.jpg 
FILENAME=$(alpr -c eu -d -n 1 /home/user/Downloads/autocheck/output.jpg |awk '{print $2}' | awk 'FNR>=2 && FNR<=4') 
if grep -Fxq "$FILENAME" /home/user/Downloads/autocheck/numbers.txt 
then 
echo CAR FOUND!, opening the gates! | while IFS= read -r line; do echo "$FILENAME, $(date) $line"; done >>/home/user/Downloads/autocheck/log.txt 
sh /home/user/Downloads/autocheck/relay-control/open.sh 2> /dev/null 
sh /home/user/Downloads/autocheck/tg.sh...