PorkPi

Raspberry Pi control for meat curing chamber

This uses a raspberry Pi to read temeperature and humidity using a DHT22 sensor and controls a fridge with the following controls:

      Temperature Too High - Turn fridge on
      Temperature Too Low - Turn fridge off + turn on heater

      Humidity Too High - turn on Fridge + Turn on heater if needed
      Humidity Too Low - turn off Fridge + Turn on humidifyer

      Circulate Air - circulate the air inside fridge

      Air_Pump - inject fresh air from outside fridge

      Weight 1 - read from load cell_1 using load cell connected to HX711 A-D converter 
      Weight 2 - read from load cell_2
      Weight 3 - read from load cell_3
      Weight 4 - read from load cell_4

Using 8 channel relay (5v, 120v) https://www.sainsmart.com/arduino-compatibles-1/relay/8-channel-dc-5v-relay-module-for-arduino-pic-arm-dsp-avr-msp430-ttl-logic.html

Load Cells https://www.amazon.com/uxcell-Electronic-Balance-Weighing-Sensor/dp/B006W2IDUO/ref=sr_1_1?s=home-garden&ie=UTF8&qid=1497712404&sr=1-1&keywords=uxcell+Electronic+Balance+Weighing+Load+Cell+Sensor+0-5Kg

HX711 DAC https://www.amazon.com/DIYmall-Weighing-Conversion-Sensors-Microcontroller/dp/B010FG9RXO/ref=sr_1_1?s=electronics&ie=UTF8&qid=1497712204&sr=8-1&keywords=DIYmall+2pcs+Hx711+Weight+Weighing+Load+Cell+Conversion+Module+Sensors+Ad+Module+for+Arduino+Microcontroller

HX711 DAC code (thanks ggurov!) https://github.com/ggurov/hx711 The code is in 'c' and I don't believe Python would work due to timing sensitiviies in reading data from the DAC.

The parameters to control the fridge are held in a google sheet (see GSPREAD below).

The output data is held in a google sheet (see gspread below)

PorkPi is monitored with a watchdog (both hard and soft)

PorkPi reports errors / crashes / restarts via email.

PorkPi responds to email commands for restart and shutdown

Files:

/etc/rc.local

Waits for wireless lan to initiate
sends email saying rebooted
starts StartPorkPi.sh shell script using screen (https://www.gnu.org/software/screen/manual/screen.html#Overview) to allow remote login to headless application
starts StartWeighing.sh shell script using screen (https://www.gnu.org/software/screen/manual/screen.html#Overview) to allow remote login to headless application

./RebootMailer

send email saying rebooted

./WaitForLan.sh

loop until get successfulping from WLAN

./PorkPi.sh

start hardware watchdog
start software watchdog (PorkPiCheckDog.sh)
send email saying Porkpi started
execute python code PorkPi.py
if crashed, send email saying crashed and restart PorkPi.py

./PorkPiCheckDog.sh

touch file
check file has been touched by PorkPi.py recently
if file has not beentouched recently, reboot
execute PorkPiCheckEmail.py to check to see if received email for reboot or restart

./PorkPiCheckEmail.py

If received email from specific account with Subject = reboot, then reboot
If received email from specific account with Subject = shutdown, then shutdown PorkPi

./StartWeighing.sh

execute HX711 with parameters to read weight of load cell and write reults to file to be picked up by PorkPi.py

./PorkPi Main python code for PorkPi

GSPREAD Gspread forms integral part of system using google sheets as a gui for input parameters as well as output.

Many thanks to burnash for this great tool https://github.com/burnash/gspread

Setting up the credentials and permissions is a little tricky but persevere.

The google workbook has 5 sheets:

Dashboard - contains the numerical and graphical status of the curing process, Temperatures, Humidity, Weights etc.
Params - contains the input parameters to control the PorkPi
Schedule - contains Temperature and Humidity settings on a daily basis so the chamber can be automatically controlled for a curingperiod
db - the data read from the DHT22 and HX711 as well as status of devices. This can get very large 5.Batches - a sheet to record information about curing batches

Scripts: Init button calls ClearCCC which deletes the database data Load Cell buttons reset the starting weight for a new batch

Link - need to figure out how to link google sheet here

There is a secondary Dash spreadsheet which links latest data onto a smaller sheet which can be viewed on a cell phone

Link - need to figure out how to link google sheet here

mlfoo/PorkPi

PorkPi