MDR Presentation
Team Frij
Department of Electrical and Computer Engineering
FRIJ
Andrew Paisner - EE
Shravan Nayak -CSE
Carlton Jones - EE
Amrit Khalsa – CSE
Department of Electrical and Computer Engineering
Adviser: Prof. David Irwin
Improving the Refrigerator
 Currently a “dumb” appliance, with no interface
with the food it holds.
 Owners are responsible for knowing what food is
or is not in the refrigerator.
 Most people rely on handwritten lists for
shopping.
 Goal: Create a smart refrigerator that knows
what products it contains and can use that data
to make prediction.
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The Frij – Goals Reiterated
 RFID and weight sensors keep status of food
items in the Frij.
 Accurate and easy product identification via
interface with UPC (barcode) database.
 Server/Database stores inventory for easy
access and predicts grocery needs.
 App displays current inventory and accesses
database-generated shopping list.
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Block Diagram from PDR
Block
Block
Block
Block
1:
2:
3:
4:
Food
Item
(with
RFID
Tag)
Carlton Jones - EE
Andrew Paisner - EE
Shravan Nayak -CSE
Amrit Khalsa - CSE
Mobile App
User
Interface
Weight
sensors
Pattern
recognition
Raspberry Pi
Server
Product
recognition
RFID
sensor
Refrigerator
Barcode
scanner
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Database
UPC
Database
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Updated Block Diagram
• Little change
• Only the “Weight Sensors”
block needs to be replaced
Mobile App
User
Interface
Food
Item
(with
RFID
Tag)
USB
scale
Pattern
recognition
Raspberry Pi
Server
Product
recognition
RFID
sensor
Refrigerator
Barcode
scanner
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Database
UPC
Database
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Block 1: Carlton Jones – Weight Sensors
 Ordered 50kg rated weight sensors.
 Created Wheatstone Bridge and Instrumentation
Amplifier.
 Tuned amplifier outputs to measurable range.
 With Andrew built ADC interface for reading via
Raspberry Pi.
 For CDR: Scrap this setup in favor of a pre-built
scale because of accuracy and tuning issues.
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Block 1: Carlton Jones – RFID
 Ordered UHF RFID reader.
 Ordered small adhesive UHF tags.
 With Amrit obtained the software that allows it to
read the tags.
 Tested sensor inside refrigerator and with
multiple and various tags.
 For CDR: Interface the RFID reader with
Raspberry Pi (can’t run manufacturer’s program
on Linux).
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Block 2: Andrew Paisner – Raspberry Pi
 Ordered and set up Raspberry Pi.
 Created program to read and send inputs from
USB barcode reader.
 Added functionality to read and send voltages
from weight sensors via ADC.
 With Amrit designed function to read and send
serial data from RFID reader.
 Program sends barcode and weight data to
server after it is scanned (not RFID as of now).
 For CDR: Connect to server via Wi-Fi.
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Block 2: Andrew Paisner – Barcodes/UPC
 Ordered USB barcode reader.
 Created program to read UPC tags on Pi.
 Researched publically available UPC databases
and their API interfaces
 Using UPCDatabase.org API created lookup
function that runs on server.
 For CDR: Add more precise product identification
for better UI. And search multiple databases.
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Block 3: Amrit Khalsa – Server
Server that will store and remove food items
•Server receives information from Raspberry PI via HTTP
POST
•Stores translated item from barcode lookup into database
•Sends and receives JSON objects
•Has functionality to remove and link data to items
PostgreSQL database
•Two tables: frijdb.items and frijdb.systeminfo
•Java code to connect to and update information in
database
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Block 3: Amrit Khalsa – Server
Communication
App
Web Server
HTTP GET
JSON Array
JSON
Object in
HTTP
POST
Server responds to
different types of
data from
Raspberry Pi:
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•Barcode numbers
•RFID numbers
•Weight sensor data
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Block 3: Amrit Khalsa – Database
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Block 4: Shravan Nayak – App
 Communicates with server
• App sends an HTTP GET request to the url of Heroku
server
• Heroku server sends a JSON array containing the JSON
object to the app which contains the product info.
• App can also send data to the server using HTTP POST
Message
 JSON Parser
• App parses the JSON array and retrieves the name and
weight of the product
• The information is stored and displayed on the using
the TextView class
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Block 4: Shravan Nayak – App
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Block 4: Shravan Nayak – Communication
HTTP GET
JSON Array
CLIENT
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SERVER
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MDR Deliverables – Proposed
 RFID reader reading tags in refrigerator.
 RFID reader and weight sensors communicating
with Raspberry Pi.
 Barcode scanner with UPC API lookup.
 Server that will store and remove food items,
weights, and their barcode/RFID data.
 Develop the UI for the app and communicate
with the server.
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MDR Deliverables – All Accomplished
 RFID reader reads tags inside refrigerator.
 RFID reader, weight sensors, and barcode
scanner communicate with Raspberry Pi.
 Server does UPC API lookup of barcodes.
 Server database stores and remove food items,
weights, and their barcode/RFID data.
 App has UI and receives database updates from
server and can send items to database.
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Proposed CDR Deliverables
 Hardware features completed.

Installed in refrigerator unobtrusively.
 USB (or other) weighing scale.
 Accurate weight sensing (can be compared to UPC).
 Integrated power supplies.
 Pi sends RFID data and is connected via Wifi.
 Accurate product description from UPC lookup.
 Server and database with product history and
predictive algorithms.
 Android UI with complete functionalities.
 Incorporating shopping list generated by server.
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