MECS

A python library for monitoring multiple sensor values on a MECS raspberry PI.

This is a draft tool at the moment, subject to change

Set up an sd-card

1. Flash raspberry pi OS (32bit lite) to an sd-card (minimum 32GB).

2. Enable headless ssh access by adding a file named ssh into the boot partition

   To do this when flashing card from Windows:

   1. Open My Computer in Windows Explorer
   2. Navigate to SD card boot partition (will show as a drive)
   3. Right click, create new text file, rename as ssh with no file suffix

   from Linux:

   cd /path/to/boot/partition
   touch ssh

3. Insert sd card into your raspberry pi

4. Log into the pi via ssh with default password: raspberry

HINT: If you have problems with this, try using putty to connect - this worked for us in the lab

Initialise the pi

1. Set the pi user password

passwd

1. Download the installation script

wget https://raw.githubusercontent.com/IESD/MECS/master/scripts/make_mecs.sh -O make_mecs.sh

1. Make the script executable

sudo chmod 777 make_mecs.sh

1. Execute the script

sudo ./make_mecs.sh

This will install a lot of stuff. You will see lots of output. Check for any errors.

A nice way to check for errors is to append the following to the above command, which sends output to a log file that you can search as well as echoing to the terminal

|& tee -a log.txt

Configuration

A configuration file is needed to use the system. A template is provided. By default, a copy of this will be placed in ~/.MECS/MECS.ini. For advanced usage, a configuration file can be specified as the first and only argument for all the following commands.

Usage

mecs-status

To get a readout of the current status

mecs-status

>***************************************************
>* MECS version: 0.3.0                             *
>***************************************************
>*         conf: /home/pi/MECS/MECS.ini            *
>*      UNIT_ID: unidentified                      *
>*           DT: 2022-10-24 13:35:40 (UTC)         *
>*       Server: [email protected]:22              *
>***************************************************

You may get an error message regarding the server configuration In which case, you should run mecs-init

mecs-init

This is essential to initialise the unit identifier, type and server configuration.

mecs-init
> Enter a new Unit ID (currently not set): MECS-0001
> Unit type (AC or DC, currently AC): AC
> Host (currently not set): my.server.com
> Username (currently not set): mecs_0001

mecs-register

Calling mecs-register will set up a public key on the server and create the necessary folders on the server and locally.

To communicate with a server requires the username and host settings to be configured using the mecs-init script.

mecs-register

You will be asked to authenticate on the server. This won't work if you don't have a server configured and ready.

In order to register, you also need destination_root and archive_folder to be set in the configuration file. the default values are fine for this

mecs-generate

To begin a long-running monitoring process which saves data files every minute.

mecs-generate

mecs-generate is automatically enabled as a service (i.e. will always be running) To manage it, use systemctl

sudo systemctl stop mecs-generate
sudo systemctl start mecs-generate
sudo systemctl disable mecs-generate
sudo systemctl enable mecs-generate

mecs-aggregate

To aggregate generated files into a single file for upload.

mecs-aggregate

This is automatically scheduled via cron so probably just leave it if you want to tweak it, edit the crontab for the pi user

crontab -e

mecs-upload

To upload aggregated data to the server

mecs-upload

Again, this is already configured in cron

To work correctly, mecs-upload requires the same server parameters to be set as for mecs-register.