A Raspberry Pi is used to take the photos, stamp them with data and store them on a USB stick.  In future iterations of this project I hope that image recognition software can be loaded onto the Pi and used to make real time conch abundance estimates.  As the sensor operates "headlessly" (i.e. with no monitor), a power button is added to put the Pi to sleep before powering down.  The following set up will take 5000 photographs 10 seconds apart automatically when you connect the Pi to a power supply.  To power off press the power button once and disconnect from the power bank when the green led on the Pi stops flashing.

Parts

Raspberry Pi 3 Model B16GB MicroSD installed with Raspbian OS

Raspberry Pi 4 Camera Module 5MP Webcam

Push Button Switch SPST NO

USB power bank (as big or little as you want, but needs to be able to power the Pi)

USB flash drive (as big or little as you want)

USB A-Male to B-Male Cable (short to link Arduino to Raspberry Pi)

USB A-Male to A-Male Cable (short to link power bank to Raspberry Pi)

Assembly

Format the flash drive as FAT32 (it probably is already), then make a folder on the flash drive called "DATA" and a subfolder in the DATA folder called "Photos".  Insert the flash drive into the bottom left usb port as you look at the 4 usb ports on the Pi.

Connect the USB port of the Arduino Uno into the bottom right USB port of the Raspberry Pi.  

Insert camera ribbon into the Pi (https://thepihut.com/blogs/raspberry-pi-tutorials/16021420-how-to-install-use-the-raspberry-pi-camera).  

Add a power button to the Pi (https://howchoo.com/g/mwnlytk3zmm/how-to-add-a-power-button-to-your-raspberry-pi).  

Connect the power bank and the Pi should start up.

Coding the Pi

Some code needs to be added to the Pi to make automatically take photos on start up.

Firstly install the code to make the power button work following step 3 of https://howchoo.com/g/mwnlytk3zmm/how-to-add-a-power-button-to-your-raspberry-pi.

Copy the following into a python editor on the Pi and save as "camera.py" in folder "/home/pi/":

import serial

from picamera import PiCamera

from time import sleep

from datetime import datetime

for i in range(5000):

   ser = serial.Serial('/dev/ttyACM0', 9600)

   line = ser.readline()

   line1 = str(line)

   line2 = line1.translate({ord(i): None for i in 'brn'})

   line2 = line2.replace("'","")

   line2 = line2.replace("\\","")

   print(line2)

   filePath = "/media/pi/DATA/Photos/"

   currentTime = datetime.now()

   picTime = currentTime.strftime("%Y.%m,%d,%H,%M,%S,")

   picName = picTime + line2 + '.jpg'

   completefilePath = filePath + picName

   timestampMessage = currentTime.strftime("%Y.%m.%d - %H:%M:%S")

   camera = PiCamera()

   camera.exposure_mode = 'sports'

   camera.resolution = (2592, 1944)

   camera.framerate = 15

   camera.annotate_text_size = 100

   camera.annotate_text = line2

   sleep(10)

   camera.capture(completefilePath)

   camera.close()

Open Terminal and type:

sudo nano /etc/rc.local

Scroll down, and just before the "exit 0" line, enter the following:

python /home/pi/camera.py &