How to Make a 4G Enabled Raspberry Pi Zero for Remote Motion Detection – Garages, Sheds Etc

sudo touch /etc/systemd/system/4gpon.service

Give it the correct permissions:

sudo chmod 644 /etc/systemd/system/4gpon.service

Then we add what we want it to do:

sudo nano /etc/systemd/system/4gpon.service

Then add the following:

[Unit]
Description=4G hat networing

[Service]
Type=forking
ExecStart=/usr/bin/pon
ExecStop=/usr/bin/poff
Restart=always

[Install]
WantedBy=multi-user.target

Then we tell the pi to use this script on startup:

sudo systemctl enable 4gpon.service

Reboot the Raspberry Pi and open a terminal window.

ps aux | grep pon

and this should show the process running the background. Nice.

2. Update route table

Executing these commands will remove the default route and replace it with the ppp0 interface for the Raspberry Pi, making it the new default.

sudo ip route delete default
sudo ip route add default dev ppp0

Then we want to add an actual ppp0 interface

sudo nano /etc/network/interfaces.d/ppp0

Then add to the file:

auto ppp0
iface ppp0 inet provider
up ip route add default dev ppp0

We have one more thing to add into the provider we would have touched on in the Twilio steps…

sudo nano /etc/ppp/peers/provider

Add at the bottom:

replacedefaultroute

3. Motion service

Similar to the previous step, we will now create a systemd service to run the script on startup, ensuring that the network is up before executing. systemd services are designed to handle dependencies and ensure proper execution. Let's proceed with creating the service:

sudo touch /etc/systemd/system/garage-motion.service

Give it the correct permissions:

sudo chmod 644 /etc/systemd/system/garage-motion.service

Then we add what we want it to do:

sudo nano /etc/systemd/system/garage-motion.service

with:

[Unit]
Description=Motion detector service
After=network.target network-online.target 4gpon.service

[Service]
Type=simple
Environment="AWS_DEFAULT_REGION=***your-region***"
Environment="AWS_ACCESS_KEY_ID=***your-key***"
Environment="AWS_SECRET_ACCESS_KEY=***your-secret-key***"
ExecStart=/bin/sh -c '/home/pi/projects/garage-motion/venv/python3 /home/pi/projects/garage-motion/venv/garage-motion.ph --serve-in-foreground'
Restart=on-abort

[Install]
WantedBy=multi-user.target

Let's start the service:

sudo systemctl start garage-motion.service

To check that the service is up, you can do:

sudo systemctl status garage-motion.service

Check if you get an email from the script!

Then we tell the pi to use this script on startup:

sudo systemctl enable garage-motion.service

Lastly, we need to ensure that the desktop display doesn't interfere with the startup of services. So far, the Raspberry Pi has been assuming that we are using a desktop setup and initializes services when an HDMI display is detected.

To resolve this, use the command sudo raspi-config to set a forced screen resolution. Select any resolution other than the monitor default option.

Afterward, shut down the Raspberry Pi by running sudo shutdown now. You're now ready to take your setup into the world and give it a try!

Step 13: Battery and Buck Module

Crimp your connectors for the battery on the wires. Connect the other end of your wires to the buck module.

CONNECT NOTHING TO YOUR BUCK MODULE OUTPUT (yet)

The position of the voltage screw that determines the output voltage (and current to some extent) is unknown. There is a risk of damaging your device if you connect it to a higher voltage. Therefore, it is crucial to initially set the voltage screw to its minimum position by turning it fully counterclockwise.

Next, connect a device that you don't mind potentially damaging, such as a fan shown in the provided pictures.

The voltage needs to be adjusted accurately, while the current will adjust itself based on the device's requirements. To set the voltage to 5.1V, use a screwdriver on the left blue component indicated in the diagram.

Step 14: Bonus – Added Camera

If you want the additional security of capturing a camera image when the motion detector is triggered, follow these steps:

1. Connect the camera to your setup.
2. Enable the camera interface by accessing the sudo raspi-config menu and enabling it in the interfaces section.
3. Refer to a guide on setting up openCV to configure the camera functionality.
4. Set up an Amazon S3 bucket with public permissions.
5. Modify the Python script to include code for uploading an image to the S3 bucket and include the image's path in the email notification. This will allow you to view the image immediately when you receive the email.

from datetime import datetime
import time
import boto3
import RPi.GPIO as GPIO
import cv2

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(13, GPIO.IN) # Middle pin defined in Step 9


client = boto3.client('sns')
s3_client = boto3.client('s3')


while True:
    i=GPIO.input(13)
    print(f'Sensitivity: {i}')
    if i==0: # When output from motion sensor is LOW
        print("No intruders",i)
        time.sleep(0.1)
    elif i==1: # When output from motion sensor is HIGH
        print("Intruder detected",i)
        now = datetime.now()
        date_time = now.strftime("%m%d%Y-%H%M%S")
        # camera bits
        cap = cv2.VideoCapture(0)
        ret, frame = cap.read()
        if ret:
            cv2.imwrite(f'intruder-{date_time}.jpg', frame)
        cap.release()
        del(cap)
        s3_client.upload_file(
            Filename=f'/intruder-{date_time}.jpg',
            Bucket='your-s3-bucket',
            Key=f'intruder-{date_time}.jpg'
        )
        # SNS send
        response = client.publish(
            TargetArn='your-arn',
            Subject='Garage update',
            Message=f'Yo, you got movement: https://your-s3-bucket.s3.eu-west-2.amazonaws.com/intruder-{date_time}.jpg',
            MessageStructure='string'
        )
        print(response['MessageId'])
    time.sleep(0.1)