SmartCup – Team 42 Harington Lee, Chirag Patil, Arjun Sharma 1

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Introduction  SmartCup  A module that attaches to the bottom of existing cups that tracks liquid levels and sends data to restaurant employees.  Simple design with built-in scalability  iOS application: Displays all cups and their beverage levels.  Hub: Performs error correction and Bluetooth transmission.  Attachment: Measures weight and cup motion. 3

Objectives  Motivations  Restaurant patrons want their drinks refilled and restaurants want to keep their customers happy (hopefully).  Better service = better reviews and higher tips.  Accuracy  Make sure data being sent is correct by detecting when the cup is not in motion.  Ease of Use  Wireless charging to keep enclosure closed.  iOS application for quick access. 4

Overall System Block Diagram 5

Attachment 6

Attachment Block Diagram 7

Attachment PCB 8

Wireless Charging Coils 9

Cockcroft Walton Generator  Voltage Multiplier and AC to DC converter  Ladder network of capacitors and Schottky diodes 10

Battery Charging  MAX1555 Battery IC  Controls charging of the battery from the output of the Cockcroft Walton Generator  Output goes to 3.3V voltage regulator  Powers weight sensor, accelerometer, amplifier, and transceiver 11

Weight Sensor  3kg load cell  1.2 mV/V Output  Instrumental Amplifier (INA122UA)  With R G = 47  Voltage ranged from 1V to 3V 12

Accelerometer  ADXL335  3 axis detection  Starting voltage reading ± 0.07 V as threshold  Mapping voltage to microcontroller  analogRead() maps input voltages of 0 – 3.3V to 0 –

Attachment Microcontroller Logic  Initial weight and accelerometer values recorded at start  Pulsing transmitter on and off  Interfered with instrumental amplifier voltage readings  Data formatted into packet and Checksum is generated  Thresholds for empty and full set in the app 14

Flowchart 15

 90/10 split between receiving and transmitting Attachment Battery Life Task Current ( Receiving)Current ( Transmitting) Total25mA29mA 16

RF Transceiver  Need to communicate data between the attachment and the hub.  RF communication is preferred.  Long distance  Multiple devices  Texas Instruments CC1000 RF transceiver  Programmable to 315/433/868/915 MHZ  Adaptable for ideal power reception at V  External impedance matching network. 17

How to Transmit RF Data? AttachmentHub 433 ±10 MHz Encoded data, known clock speed, known baud rate 433 ± ??? MHz Unknown data, possible clock drift, unknown baud rate?? TransmitterReceiver 18

Packet Transmission Protocol PreambleCIByte 1Byte 2Byte 3 EOM Data Packet (35 bytes) 19

Clock Data Recovery **Keysight, Electrical and Optical Clock Data Recovery Solutions 20

Impedance Matching Network 88-j26 Ω 50 Ω 21

LC Network Simulation 22

Transmitter Antenna Response dBM at 1.5 feet 23

Transmitter Antenna Response dBm at 30 feet 24

Receiver Harmonic Response 25

Attachment PCB Schematic 26

Attachment PCB Layout 27

Hub  Performs error correction on incoming RF packet.  Transmits data via Bluetooth. 28

Hub Block Diagram 29

Hub Microcontroller Code  Primarily does ECC and packet conversion between async systems.  Maintain message FIFO from attachment. PreambleCIByte 1Byte 2Byte 3 EOM PreambleUUID Header Advert. Channel Payload Access ID Prefix EOM RF packet Bluetooth packet 30

Bluetooth Module  HM-10 Bluetooth 4.0 module  4-wire SPI interface  Switched to serial due to solder issues 31

Hub PCB Schematic 32

Hub PCB Layout 33

Software 34

iOS CoreBluetooth  iOS7 has a provided CoreBluetooth SDK  Peripheral: Bluetooth Hub (uses UUID to connect)  Central: Phone 35

Peripheral Broadcasting  Important to understand layout of the broadcasted data  CBService: Weight Info  Characteristic 1: Cup ID  Characteristic 2: Cup Weight 36

Multiple Weight Values  Each Cup has to have its own view controller 37

User Interface Decisions  Green  100%-51%  Yellow  50%-26%  Red  25%-0% 38

System Integration  Completely Integrated  Weight Sensor  Microcontroller code  Bluetooth/RF  iOS App  Partially Integrated  Accelerometer 39

Future Work  Multiple Attachments  (2400 bits/sec)(1byte/8bits)(1device/35bytes)(10sec) = 85 attachments  BLE range  Use Android Instead  Minimize physical footprint  3D Print/Moldable Plastic Attachment  Cup/Table layout 40