MVP II

NOTE: 12/04/2017 - This is the release build of the MVP ver. 2.1. The functionality is the same as ver 1, but there has been some cleaning up of the code and reorganization. The goal of this package is to have a single script that will extract and build the entire environment on a 'stretch' release of Raspbian.

Background

Code and instructions for building the 'brain' of the controled environment hydroponics unit. It is mostly a collection of python code that runs on a Raspberry Pi (or similar device). See the OpenAg forums for discussion and issues:

The MVP (Minimal Viable Product) is a simplified version of the MIT OpenAg Food Computer.

##Changes

• Persistent variables are now in Python files (env.py and variable.py). Shelf has gone away.
• Cron is loaded from a file, no longer needing to be edited.
• smbus2 has been substituted for smbus. This version gives more precision to the si7021 sensor readings.

Architecture:

The MVP brain is mostly python scripts involed using cron as the scheduler.
Python and cron are built into the Raspbian OS, and the Raspberry library to manipulate GPIO pins is already loaded.

The Python is modular so additions and changes can easily be made without affecting the whole system.

• Scheduling Control (cron)
  • Image capture (webcam.sh)
  • Log Sensors (logSensors.py)
  • Turn lights On (setLightOn.py)
  • Tirm lights Off (setLightOff.py)
  • Check Temperature (adjustThermostat.py)
  • Refresh charts and picture for the UI (render.sh)

Data storage is in a csv formatted (without header) flat file (/home/pi/MVP/data/data.txt) - this will likely be deprected in the future. CouchDB is the main data storage system, and will provide easy replication to the cloud in the future.

For more information on Cron see:

Hardware Build:

Fan: There are two fans, one for circulation and one for exhausting excess heat These can run off the Raspberry's 5V or from a external 12V transformer

Temperature/Humidity Sensor A si7021 sensor on an I2C bus is used for temperature and humidity. See the following for (instructions)[https://learn.adafruit.com/adafruit-si7021-temperature-plus-humidity-sensor/overview] on use and wiring.

Webcam A standard USB camera is used for imaging (though the Raspberry Pi camera is an option). See here for instructions

Relay A set of relays controled by GPIO pins is used to turn lights on and off (120V), and the exhaust fan (12V)

Pin Assignment:

Refer to the following diagram for the Raspberry's pin names:

Code follows the board number convention.

• '3 - SDA to si7021'
• '5 - SCL to si7021'
• '29 - light relay (relay #4)'
• '31 - (reserved for relay #3)'
• '33 - (reserved for relay #2)'
• '35 - GPIO13 fan control (relay #1)'

Build Activities

Assumptions:

1. NOOB install of Raspbian on Raspberry Pi
2. The Raspbian system has been configured
   • for localization (time, timezone)
   • wifi is established and connected
   • I2C has been enabled
3. 32G SD card to hold data
4. Sensors and relay are wired to the Pi. If you try to run the code without sensors, some of it will error out (I/O Error, I noticed in the getTempC() function). This will ripple up to error out the cron job for logSensorData.py.

Software Build

The build scripts are the documentation. If you want to build things yourself, follow the scripts (/home/pi/MVP/setup). The initial script is not in Github, as the script extracts the files from Github and changes the permissions on /home/pi/MVP/setup/releaseScript.sh. From within your Raspberry Pi, cut and paste the following lines of code to to a text file and name is buildScript.sh. Then change, the permissions to make it executable (from a File Manager, right click on the file and select "Properties". In the "Permissions" tab, under "Execute", select "Anyone" and then click "OK"). Then open a terminal window and type in "/buildScript.sh.

#!/bin/sh

# Part 1
# Semi-generic script to get and install github archive
# Author: Howard Webb
# Date: 11/16/2017

# This script assumes you are running on your Raspberry Pi with (Stretch) Raspbian installed.
# Internet is connected
# You have configured the local environment (keyboard, timezone)
# You have adjusted the Pi Preferences (Configuration)
#   Enable the camera interface
#   Enable I2C
#   Optionally (suggested) enable SSH, VCN and 1-Wire

# Get the release from Github
# Extract it to the proper directory
# Make the build script executable
# Run the release specific build script

###### Declarations #######################


RED='\033[31;47m'   # Define red text
NC='\033[0m'        # Define default text

EXTRACT=/home/pi/unpack    # Working directory for download and unzipping
TARGET=/home/pi/MVP       # Location for MVP
RELEASE=OpenAg-MVP-II             # Package (repository) to download 
GITHUB=https://github.com/webbhm/$RELEASE/archive/master.zip    # Address of Github archive

echo $EXTRACT
echo $TARGET
echo $RELEASE
echo $GITHUB

###### Error handling function ###################

PROGNAME=$(basename $0)

error_exit()
{
	echo ${RED} $(date +"%D %T") "${PROGNAME}: ${1:="Unknown Error"}" ${NC} 1>&2
	tput sgr0
	exit 1
}

####### Start Build ######################
echo "##### Update Existing System #####"
sudo apt-get update

echo "##### Starting to build directories #####"
# Build target directory
mkdir -p $TARGET || error_exit "Failure to build target directory"
echo $(date +"%D %T") $TARGET" built"

echo "##### Starting download of MVP from Github #####"
# Download MVP from GitHub and install
# Build extraction directory
mkdir -p $EXTRACT || error_exit "Failure to build working directory"
echo $(date +"%D %T") "Directory built"
cd $EXTRACT

# Download from Github
wget -N $GITHUB -O mvp.zip || error_exit "Failure to download zip file"
echo $(date +"%D %T") "MVP Github downloaded"

cd $EXTRACT

# Unzip the files, overwrite older existing files without prompting
unzip -uo $EXTRACT/mvp.zip || error_exit "Failure unzipping file"
echo $(date +"%D %T") "MVP unzipped"

cd $EXTRACT/$RELEASE-master/MVP || error_exit "Failure moving to "$EXTRACT/$RELEASE"-master"

# Move to proper directory
mv * $TARGET
echo $(date +"%D %T") "MVP moved"

# Clean up temporary extraction directory
rm -r $EXTRACT
echo $(date +"%D %T") $EXTRACT" removed"

########################################
echo "##### Relsease Specific Build #####"
# Complete the release specific build - this is the CouchDB extract

# Set permissions on script
chmod +x $TARGET/setup/releaseScript.sh || error_exit "Failure setting permissions on release script (check file exists in MVP/scripts)"
echo $(date +"%D %T") "Run permissions set"

# Run script in download
bash $TARGET/setup/releaseScript.sh || error_exit "Failure running release specific script"
echo $(date +"%D %T") "Install Complete"

Manual Build

The following scripts (in /home/pi/MVP/scripts) can be run separately and in sequence if any errors are encountered. Look within the scripts for single commands.

• releaseScript.sh calls the following scripts:
• releaseScript_DB.sh - installs the CouchDB code
• releaseScript_Local.sh - builds libraries, starts the database and initializes things
• releaseScript_Test.sh - calls Validate.sh to test the system
• releaseScript_Final.sh - configures start-up and loads cron

To Do:

1. Add a watchdog to the Raspberry
2. Fix the cron email notifications

Future Development (in no priority):

• GUI interface for setting persistent variables (could be local)
• Add a pump for when have to be away for a while and need to refill the reservoir.
• Light control for controlable LEDs