MBP Aquarium CAM

This repository contains the MBP Aquarium CAM support scripts. This is, a script for retrieving data from the Arduino data acquisition unit, as well for start the FFmpeg streaming process of the video from the underwater camera to the TWitch on-line streaming service.

Installation instructions

Set up a user to run the process

We suggest to set up a dedicated user to run the FFmpeg streamer and other commands. This especially aplies for cases when these script are hosted on a shared system.

The below set of commands created the user aquarium-cam with GID = UID = 5001. If you're going to run it as suggested, please adopt this to your system:
```
groupadd -g 5001 aquarium-cam
useradd -u 5001 -g aquarium-cam -m -s /bin/bash -c "MBP Aquarium CAM" aquarium-cam
```
NOTE / ATTENTION: The rest of this document supposed the mentioned user was created, as well its home directory, etc. So, adopt acordigly.
TTF fonts setup

Data from the measurement unit is written as an overlay to the streamed video. For this, Open-Sans fonts are being used which are NOT included in this repository, but the end-user has to set them up. That is, download the .zip archive and extract the OpenSans-Regular.ttf fond file from it.
```
cd ~aquarium-cam

wget -O open-sans.zip "https://www.fontsquirrel.com/fonts/download/open-sans"

unzip open-sans.zip OpenSans-Regular.ttf

rm open-sans.zip
```

Clone the code and copy needed scripts

cd ~aquarium-cam

git clone https://github.com/petervalencic/MBPKamera.git aquarium-cam.git

cp -v aquarium-cam.git/aquarium-cam.* .

Update the configuration file

Please, edit aquarium-cam.conf. You'll need to update at least following settings:
- ARDUINO_ROOT_URI
- AQUARIUM_CAM_IP
- FFMPEG_TWITCH_KEY
Create the temporary data storage directory

On Ubuntu 18.04 LTS we used tmpfiles.d facility for this (see man tmpfiles.d for details).

So, create /etc/tmpfiles.d/aquarium-cam.conf with following content:
```
#Type Path               Mode UID           GID             Age Argument
D    /run/aquarium-cam   2755 aquarium-cam  aquarium-cam    3d  -
```
Check if all is OK

NOTE: Make sure you're running these commands as user aquarium-cam - use id to check what user you're logged in currently.
- Retrieve a new set of measurements from Arduino and check its content
```
./aquarium-cam.sh --op GET-DATA
cat /var/run/aquarium-cam/data.txt
```
- Check if FFmpeg is running and if not, start it
```
./aquarium-cam.sh --op CHECK-PROC

./aquarium-cam.sh --op CHECK-PROC
```
  ^^^
  The second command should have output:
  Aquarium CAM streaming -> OK
Create cron jobs The target is to retrieve fresh measurement data every minute, as well to check if FFmpeg is still running every minute and if not, reastart it. Therefore edit the user crontab - as root use crontab -u aquarium-cam -e and add following commands:
```
# Retrieve fresh data from Arduino measurement unit
* * * * *   cd ~aquarium-cam && ./aquarium-cam.sh --op GET-DATA   1>/dev/null

# Check if FFmpeg is running, if not, start it
* * * * *   cd ~aquarium-cam && sleep 5 && ./aquarium-cam.sh --op CHECK-PROC 1>/dev/null
```
^^^
ATTENTION: The script logic check if two instances of the same script are running at the same time. Therefore, the FFmpeg check should be deferred - this is what sleep 5 is there for.