This system is an inexpensive and flexible wireless Web or IOT (internet of things) based controller for drying Fruit, Fruit leather, Vegetables, Yoghurt making and Raising Bread. You can use your own homemade or some commercial dehydrator. The system is connected to Amazon cloud using AWS internet of things to smart control. It's based on https://github.com/steve71/RasPiBrew project.

This program will control an electric heating element in a dehydrator to set the air temperature. All status included temperature, humidity is logged localy to file in CSV format to display on web browser or android device wirelessly approx. every fwe seconds (sleep time). The duty cycle and temperature is plotted in real time. A Type C PID algorithm has been successfully implemented to automatically control the heating element when the desired temperature is set. CSV is transformed to JSON file and both send to AWS S3 to display temperature, humidity, weight diagram and spreadsheet for analytical purpose. Status is also logged to AWS IOT to display on Android device and to control dehydrator by Android device. So there no need to run web server on Raspberry PI.

For bootstrap multi-heater and GPIO switch control version set template element to raspidry_bootstrap.html in config.xml. For original version set template to raspidry.html. The config.xml file explains how to setup for one, two or three heaters. The number of heaters and GPIO switches can easily be expanded in the software. The same raspidry.py code supports both versions.

• Programmable [PID Controller] for precise air heater temperature control
• Programmable duty cycle time, and dry time
• Selectable options (Fruit, Fruit leather, Vegetables, Yoghurt making, Raising Bread)
• Controllable from web browser, Android device (iPhone coming soon) on Wifi network
• LCD readout for system status, toggle buttons for operation
• AWS S3 data archiving for analysing
• AWS IOT register a status of dehydrator and commands from Android device
• AWS Simple Notification Service (SNS) send an alarm, when temperature exceeded high level or process is interupted
• Visualization using open source spreadsheet and plot javascript

##Hardware and Software Setup Information:

<img src="https://github.com/bmili/RasPiDry/raw/images/PID_Tuning.png" alt="" width="954 height="476.5" />

(https://github.com/bmili/RasPiDry/raw/images/PID_Temp_Control.png)

The temp plot shows temperature in degrees F or C over time in seconds.
The heat plot shows duty cycle percentage over time in seconds.

There is RasPiBrew New Version 1.1.4 of Android application on Google Play

RasPiDry of Android application is comming soon. And also RasPiDry of Android AWS IOT application

There is Node.js application, which simulate simple IOT application. You need Node.js environment as described in https://github.com/aws/aws-iot-device-sdk-js/blob/master/README.md and install aws-iot-device-sdk-js-master on your Node server. Then you can run
"node temperature-control-client.js -f ~/certificate -g eu-west-1"

A low cost credit card sized Raspberry Pi computer is an inexpensive and very expandable solution to controlling processes. In our case heating process is controlled by measuring the temperature, humidity and weight. Used in combination with a Saint Smart control relay , temperature sensors and a usb wifi dongle, a wirelessly controlled temperature controller is developed. The Raspberry Pi can run a web server to communicate with a browser on a PC or smartphone. In a case of connection to AWS IOT (internet of things), there is no need to run web server on RPI. You need only Android device running android application .

Electronics used to test:

• Raspberry Pi B+,
• Raspberry Pi Accessories Prototype Pi Plate,
• Sain Smart 4 chanell control relay ,
• DS18B20 digital thermometer,
• 20x4 LCD and LCD117 kit (serial interface),
• 4.7k resistor, 1k resistor, 1N4001 diode, and 2N4401 transistor.,2K resistor,10K resistor,TansistorR PN2222A
• Edimax EW-7811UN dongle is used.

Information on Raspberry Pi low-level peripherals:
http://elinux.org/RPi_Low-level_peripherals

Load Operating System onto SDCard

Download the raspberry pi operating system: Raspberry Pi Downloads Use Win32DiskImager to install onto SDCARD.

In terminal type: sudo raspi-config

Expand File System and set Internationalization options

Note: If using LCD go into Advanced Options and disable kernel messages on the serial connection

In terminal type:

sudo apt-get update
sudo apt-get upgrade

Follow the RasPi beginners guide to get up and running:

Run sudo setupcon once manually after the keyboard is setup otherwise you may have long boot times.

Lookup Compatible USB wifi devices and install the drivers:

To set up a static ip address use the following in /etc/network/interfaces:

auto lo

iface lo inet loopback
iface eth0 inet static

auto wlan0
iface wlan0 inet static
address 192.168.1.103
netmask 255.255.255.0
gateway 192.168.1.1

If no wireless password use:

wireless-essid linksys

Otherwise use the following:

wpa-ssid "ssid"
wpa-psk "wireless_key_passphrase" 

with the correct ssid (router name) and wireless_key_passphrase.

Tutorial on setting up a static IP address Tutorial on setting up wifi device on linux

Python Modules: Install easy_install 'wget --no-check-certificate https://bootstrap.pypa.io/ez_setup.py' 'python ez_setup.py --insecure'

Install pip (package installer): 'sudo apt-get install python-setuptools' 'sudo easy_install pip'

Install PySerial: sudo pip install pyserial PySerial Info

Install Python i2c and smbus: 'sudo apt-get install python-smbus' smbus info

Install Flask: 'sudo apt-get install python-dev' 'sudo apt-get install libpcre3-dev' 'sudo pip install Flask' Flask Info

Install GPIO: 'sudo apt-get install python-dev python-rpi.gpio'

In Raspberry Pi terminal window: 'sudo bash' 'cd /var' 'mkdir www'

Copy software to /var/www preserving the directory structure.

At the command prompt type: 'sudo nano /boot/config.txt' At the bottom of the file add the line: 'dtoverlay=w1-gpio' Save the file and then reboot.

Replace the temp sensor id in config.xml with the id of your DS18B20 temperature sensor found in the /sys/bus/w1/devices/ directory on the Raspberry Pi.

Start Putty on Windows and type login name and password. Program must be run as superuser: Type sudo bash Start program by typing: python raspibrew Next, start the web browser on a computer on your network. If ip address of the Raspberry Pi is 192.168.1.8 then point the browser to http://192.168.1.8:88

AWS IoT Makes Things Smarter and IOT Food Dehydrator will bi smart Food Dehydrator.

To start with AWS IOT frst install AWS CLI (Ubuntu 14):

'sudo apt-get update;sudo apt-get install python'
'sudo apt-get install python-pip'
'sudo pip install awscli'

To connect client to AWS, first run config command

'sudo aws configure'

When you are asked, add your keys and region.

AWS Access Key ID [None]: AKIAIèèæYBTZUDMXWFUTA AWS Secret Access Key [None]: 3Pp9eTt/j0Ahpol37žžèiSuuckmM581LFRUOZfo Default region name [None]: eu-west-1 Default output format [None]: ENTER

The AWS credentials you configure in the AWS CLI must be the credentials for an IAM user that has permissions to perform IAM and IoT operations used in this quickstart. 

aws iam create-user --user-name Boris { "User": { "UserName": "Boris", "Path": "/", "CreateDate": "2016-01-15T19:03:24.851Z", "UserId": "xyDAII32LV6WXXMOM63xy", "Arn": "arn:aws:iam::112200121337:user/Boris" } }

To connect a thing to AWS IoT, we first create a device in the Thing Registry.

aws iot create-thing --thing-name "FoodDehydrator" { "thingArn": "arn:aws:iot:eu-west-1:112200121337:thing/FoodDehydrator", "thingName": "FoodDehydrator" }

Secure Communication Between a Device and AWS IoT Communication between a thing and AWS IoT is protected through the use of X.509 certificates

'aws iot create-keys-and-certificate --set-as-active --certificate-pem-outfile cert.pem --public-key-outfile publicKey.pem --private-key-outfile privateKey.pem'

'aws iot create-keys-and-certificate --set-as-active --certificate-pem-outfile cert.pem --public-key-outfile publicKey.pem --private-key-outfile privateKey.pem'

'aws iot create-policy --policy-name "PubSubFoodDehydratorTopic" --policy-document file://iot-policy'

Attach your Certificate to Your Device You use the attach-thing-principal CLI command to attach a certificate to a thing.  'aws iot attach-thing-principal --thing-name "FoodDehydrator" --principal "arn:aws:iot:eu-west-1:112200121337:cert/370c8ccf949787dab6aa7314b5ea4eb2ce016c30418e5bf4b338e06854c86516"'

Verify MQTT Subscribe and Publish The steps in this section show you how to verify you can use your certificate to communicate with AWS IoT over MQTT. You will use an MQTT client to subscribe and publish to an MQTT topic. MQTT clients require a root CA certificate to authenticate with AWS IoT. Download the root CA certificate file from root certificate.

Install mosquitto:

'sudo apt-get install mosquitto-clients on debian or

Check mosquitto pi@raspberrypi ~ $ mosquitto_pub -t test -f mqtt/mosquitto/publish.txt -d Client mosqpub/14824-raspberry sending CONNECT Client mosqpub/14824-raspberry received CONNACK Client mosqpub/14824-raspberry sending PUBLISH (d0, q0, r0, m1, 'test', ... (6 bytes)) Client mosqpub/14824-raspberry sending DISCONNECT

Run mosquitto subscriber:

mosquitto_sub --cafile  $HOME/certificate/root-CA.crt --cert $HOME/fooddehydrator/cert.pem --key  $HOME/fooddehydrator/privateKey.pem  -h "A9HHD5G1IXZ9I.iot.eu-west-1.amazonaws.com" -p 8883 -q 1 -d -t '$aws/things/FoodDehydrator/shadow/update/rejected'

##Running the temperature control Simulation over AWS IOT

To tun mosquitto in Node.js to simulate temperature control over AWS IOT(Terminal Window 1) in Node.js first install:

"npm install mqtt -g" "npm install minimist" "node temperature-control_client.js -f ~/certificate "

Check mqtt "mqtt sub -t 'hello' -h 'test.mosquitto.org' -v"

To run mqtt in python install paho library

"pip install paho-mqtt"

In python you shuld add

import paho.mqtt.client as mqtt

client = paho.Client() client.on_connect = on_connect client.connect(“XXXXXYYYYY.iot.eu-west-1.amazonaws.com", port=8883) #AWS IoT service hostname and portno

To send data to AWS S3 in python, you need to install boto library. Boto3 provide native support in Python versions 2.6.5+, 2.7, 3.3, and 3.4.

"pip install boto3"

Create a new file: /etc/init.d/raspibrew as superuser and insert the following script:

#! /bin/sh
# /etc/init.d/raspidry

### BEGIN INIT INFO
# Provides:          raspidry
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Simple script to start a program at boot
# Description:       A simple script from www.stuffaboutcode.com which will start / st$
### END INIT INFO

# If you want a command to always run, put it here

# Carry out specific functions when asked to by the system
case "$1" in
    start)
        echo "Starting RasPiBrew"
        # run application you want to start
        python /var/www/raspidry.py
    ;;
    stop)
        echo "Stopping RasPiBrew"
        # kill application you want to stop
        killall python
        python /var/www/cleanupGPIO.py
    ;;
*)
    echo "Usage: /etc/init.d/raspidry {start|stop}"
    exit 1
    ;;
esac

exit 0

Make script executable: sudo chmod 755 /etc/init.d/raspibrew

Register script to be run at start-up: sudo update-rc.d raspibrew defaults

To Remove script from start-up: sudo update-rc.d -f raspibrew remove

To test starting the program: sudo /etc/init.d/raspibrew start

To test stopping the program: sudo /etc/init.d/raspibrew stop

Run RasPi Program at Start Up Info

###IDE for Development:

Install Eclipse Luna on your computer:

This is used for programming in Python, Javascript, web page design and a synchronization with Raspberry Pi

<img src="http://iothome.s3.amazonaws.com/image/dev.png" alt="Eclipse Luna" width="954 height="776.5" />

The language for the server side software is Python for rapid development. The web server/framework is web.py. Multiple processes connected with pipes to communicate between them are used. For instance, one process can only get the temperature while another turns a heating element on and off. A third parent temp control process can control the heating process with information from the temp process and relay the information back to the web server.

On the client side jQuery and various plugins can be used to display data such as line charts and gauges. Mouse overs on the temperature plot will show the time and temp for the individual points. It is currently working in a Firefox and Chrome Browser.

jQuery and two jQuery plugins (jsGauge and Flot) are used in the client:
http://jquery.com
http://code.google.com/p/jsgauge/
http://code.google.com/p/flot/

The PID algorithm was translated from C code to Python. The C code was from "PID Controller Calculus with full C source source code" by Emile van de Logt An explanation on how to tune it is from the following web site:
http://www.vandelogt.nl/nl_regelen_pid.php

The PID can be tuned very simply via the Ziegler-Nichols open loop method. Just follow the directions in the controller interface screen, highlight the sloped line in the temperature plot and the parameters are automatically calculated. After tuning with the Ziegler-Nichols method the parameters still needed adjustment because there was an overshoot of about 2 degrees in my system. I did not want the temperature to go past the setpoint since it takes a long time to come back down. Therefore, the parameters were adjusted to eliminate the overshoot. For this particular system the Ti term was more than doubled and the Td parameter was set to about a quarter of the open loop calculated value. Also a simple moving average was used on the temperature data that was fed to the PID controller to help improve performance. Tuning the parameters via the Integral of Time weighted Absolute Error (ITAE-Load) would provide the best results as described on van de Logt's website above.

#Dehydrator

##Dehydrator Equipment

##Dehydrator Hardware Links