1. The Smart Kegerator
EE-595
Group 1
Brandon Bartell
Nick
Sneha Juvekar
Anthony
Hector

2. Insert Picture Slide of Group Members Here

3. Project: Smart Kegerator
Refrigerating, dispensing, and monitoring device for compressed fluids
Displays temperature
Displays liquid content
Prevents unauthorized usage

4. Project: Smart Kegerator

5. Project: Smart Kegerator
Temperature
sensor
Display
Signal Conditioner
Power Supply
Scale / Converter
Keypad/Security
Flow solenoid
Nick
Hector
Brandon
Sneha
Anthony

6. Performance Requirements
Keypad Matrix: 3 columns, 4 rows
Key Definitions: 0-9 digits, enter, clear
Sensory: Temperature and Weight
Temperature accurate within 0.5 °C
Weight Scale accurate within 0.8 lbs

7. Performance Requirements
Power Modes: ON/OFF
Power Saving Modes: Standby

8. Standard Requirements
Operating Temperature Range: 10°C to 32.22°C
Operating Humidity Range: 0-100% Non condensing
Operating Altitude Range: -300ft to 15,000ft
Storage Temperature Range: -50°C to 65°C
Storage Humidity Range: 0-100% Non condensing
Storage Pressure Range: 0.5 to 1.5 ATM
Sources: 120 VAC
Power Consumption: 74 W

9. Standard Requirements
Volume: 17.6 ft3
Shipping Container Size: 31in.×68in.×28in.
Mass: fridge plus add-ons
Maximum Parts Count: 50 parts
Maximum Unique Parts Count: 20 parts
Full Warranty Period: 1 years
Service Strategy: Field Repair or Dispose
Product Life: 20 years or more

10. Key Technical Risk & Problem Areas
These are some key technical risks that we believe might hamper our overall efforts
Sensor interfacing
Programming language selection - integration
Potential long lead time on various components
Size of prototype (transportation, work –space availability)
Component response to low temperatures
Power supply interfacing (step-down transformers, AC\DC conversion)
Signal control and processing
Microcontroller limitations
High costs of components and supplies

11. EMC Standards
IEC : Limitation of voltage fluctuations and flicker in low-voltage supplies <16A
Required because a low end voltage flicker could damage the compressor
IEC : Surge Immunity tests
Required because the microcontroller and other components need to be protected from potential power surges
IEC : Voltage dips, short interruptions, and variations
Required because brown out conditions will affect keypad thereby affecting overall performance

12. Safety Standards CSA C22.2 No. 14-95
Applies for control and protective devices. Control devices covered in this standard include: pushbutton; flow-, pressure- operated switches; and proximity switches.
IEC
Applies for the safety of motor-compressors, their control and protection system which are intended for household purposes.
UL 873
Temperature-Indicating and -Regulating Equipment: requirements for electrical equipment for control for refrigeration

13. Specific Safety Requirements
Ground Fault Circuit Interrupter (GFCI)
Connected in series with the power source. Needed because there will be electronics in a potentially wet environment: the sensors near the keg.
Anti-tipping Mercury Switch
If the kegerator tips over, this will turn off the compressor.

14. Example of Simple Gantt Chart showing dependencies

15. Block Prototyping Plan Template
Name
Block Area (cm2)
Total PCB
Area (cm2)
PCB
Substrate
Type
Comp
Attachment
Socketed
Components
Types of
Connectors
Nick 72 65
Plastic, pads, buses
Solder
Relay, resistors, LEDs
IEC, Circular, PCB Mount
Hector
204
194
Diodes, resistors, capacitors, etc.
IEC, PCB mount
Sneha
105 92
ICs, LEDs
IEC, PCB Mount
Anthony 81 66
ICs, Relays
Brandon
112
101
Diodes, IC, resistors, capacitors,
IEC

16. Block Prototyping Plan Template
The PCB will have pads and a bus
All socketed components will be soldered or din rail mounted
All Connectors will be IEC, Circular, or PCB mount.
A minimum of 10 components will be used by each block

17. Block Prototyping Plan Template
Estimation Summary
Estimated vs 400 availability.
$ Estimated vs $600 available investment
3.29 % of total manpower for system design tasks, detailed design tasks, verification tasks, and documentation tasks:
Suggested down/up scope if needed:
Added CPLD Control, Electronic Pressure Regulator, Volume/Flow Control

18. Temperature Sensor Block
Owner: Anthony Futterer
The purpose of the temperature sensor is to monitor the temperature inside
the kegerator unit and serve to inform the user via the display block of the
temperature in degrees C.

19. Performance Requirements
Accurate to 0.5 degrees C.
Provide a user mountable probe device for internal placement.
Provide an inline shielded signal cable for transmittance of the output signal to the signal conditioner.
Provide a separate signal conditioning circuit for output scaling to suitable A/D converter range in display block.

20. Interface with display
Block Breakdown
4-30 VDC input from power supply
AD590
Temperature
Sensor Probe
Signal Conditioner
Interface with display
A/D converter

21. Block Detail Design
AD590M measures temperature in K to 0.5 degrees accuracy.
LM741 and LM1458 Dual Operational Amplifiers serve as signal amplification devices from uA to mA needed.
AD580 high precision voltage comparator serves as error correction tool.

22. Signal Conditioning Block
Owner: Anthony Futterer
The purpose of the signal conditioner is to convert the load cell output signal
to a usable A/D converter signal amplitude for the display block.

23. Performance Requirements
Provide an input port for the signal from the load cell.
Provide an inline shielded signal cable for transmittance of the output signal to the display.
Provide a separate signal conditioning circuit for output scaling to suitable A/D converter range in display block.

24. Block Signal Table

25. Interface with display
Block Breakdown
24 VDC input from power supply
Load Cell
Input Connector
Signal Conditioning
Circuitry
Interface with display
A/D converter

26. Block Detail Design Takes in Load Cell Signal.
LM741 and LM1458 Dual Operational Amplifiers serve as signal amplification devices from uA to mA needed.
AD580 high precision voltage comparator serves as error correction tool.

27. Reliability Assessment, Growth (Sig-Cond/Temp Sensor Block)
The Team Used the Method B reliability Database
Total from my combined blocks spreadsheet was
Total MTBF was therefore
The dominant parts of unreliability was the MC1403U Precision Serial Voltage Reference IC
This could be improved by using the AD580 Voltage Reference IC or a similar part with a higher operating temperature than the MC1403U.

28. Owner: Brandon Bartell
Keypad Block
Owner: Brandon Bartell
The main purpose of the keypad block is to provide a security feature by making the user enter a 4digit-code. When the code is entered the user will be allowed to pour their drink.
Implementation of a controlling device will also provide metered pouring to either 12 or 16 ounce depending on user selection.

29. Block Detail Design
Anticipated appearance of actual keypad

30. Interface with solenoid block
Block Breakdown
In from power supply block
Control/Timer
Power
User interface (Keys)
Interface with solenoid block
Out to solenoid block

31. Block to Block Interface

32. Block Detail Design
The EEPROM memory protects the stored data in case of power failure.
Over 100 million combinations are possible for the user codes.
Two other codes can be used to allow user to get a metered pour of 12 or 16 ounces.
Two separate relay outputs.
Audible key operation - optional

33. Performance requirements for keypad block
Accuracy:
-Within .1% to .2%
User Indicators:
-Indicator Parameter: 3 LEDs.
-Applicable User Interface Type: Analog 3x4 keypad matrix
-Mechanical Interfaces: Interface with solenoid block via
relay signal.
-Analog Input Signal Frequency: 67Hz.
-Power Signal Input Frequency: 57 – 63Hz.

34. Standard requirements for keypad block
Min. Operational Ambient Temperature Range: 0 to 50 degree Celsius.
Min. Operational/Storage Ambient Humidity Range: 100 %Rh.
Min. Storage Ambient Temperature Range: -50 to 65 degree Celsius.
Applicable Safety Standards: UL 873.
Applicable EMC Standards: IEC
Estimated Max. Production Lifetime: 5 years.
Reliability in MTBF: 0.09 years.
Service Strategy: Repair.

35. Safety requirements for keypad block
Compliance with IEC
Compliance with IEC
Compliance with IEC
Compliance with IEC
Compliance CISPR11- RF Emissions

36. Block Detail Design Specifications relay outputs: output 1: 5 Amp
output 2: 1 Amp, N.C. & N.O. dry contacts, DC 30V max.
operating voltage: DC 12V (DC 10-14V)
current drain: mA
duress output: NPN transistor with open collector output, switches to ground (-) when activated, 100mA/25V DC max.
codes available: User 1 & 2, Super User, Master, Duress and Accelerated codes
code combinations:
dimensions: 4.6" x 2.9" x 1.9"
weight: ± 6.5oz (net), ± 8.1oz (gross)

37. Reliability Assessment, Growth (Keypad Block)
Total FIT’S =
MBTF =
Dominant unreliable parts are LM741 Op-Amp and Switches
Obvious resolution for unreliable parts is to make the switches waterproof as well as dustproof and of a better quality to increase reliability factors as well as better component selection on the Op-Amp.

38. Power Supply Block Owner: Hector Gomez
The purpose of the power supply is to supply energy to all the blocks. It will also provide overload protection in case of short circuit in the product.

39. Performance Requirements
To deliver power at +/- 5% of required voltages with low noise.
To supply enough current for all the blocks
To turn off entire blocks with a toggle switch

40. Power Supply Block to Block Interface

41. Block Breakdown Temperature sensor Keypad/Security Power Supply AC/DC
60HZ
Power Supply
AC/DC
120AC
5DC/24DC
3.0 Amp
Scale
Signal conditioner
Display
Flow solenoid
Hector

42. Block Detail Design Transformer steps down voltage
Diode Bridge does the conversion of AC to DC Voltage with 3amps rated diodes and 10% ripple
First phase capacitor used to eliminate transients and makes voltage linear
LM317T regulates voltage and offers current limiting in case of failures in the system.

43. Block Detail Design Specifications operating voltage: 120VAC +/- 10%
60 Hz Input +/- 3 Hz
Output Voltage DC 5-12V
Output Current 3A
User Interfaces: Toggle switch (to turn off power)
dimensions: 8’’ X 10”
weight: 18oz (net), ± 8.1oz (gross)

44. Basic Operation
Transformer + Rectifier + Smoothing + Regulator

45. Transformer turns ratio = Vp = Np and power out = power in Vs Ns
 =  Np
   and   
power out = power in    Vs Ns
Vs × Is = Vp × Ip
Vp = primary (input) voltage Np = number of turns on primary coil Ip  = primary (input) current
   
Vs = secondary (output) voltage Ns = number of turns on secondary coil Is  = secondary (output) current

46. Bridge Rectifier

47. Output with a Small Ripple

48. Complete Rectification
10% ripple, C= (5 X I) / Vs X f
C  = smoothing capacitance in farads (F) Io  = output current from the supply in amps (A) Vs = supply voltage in volts (V), this is the peak value of the unsmoothed DC f    = frequency of the AC supply in hertz (Hz)

49. Reliability Analysis of Power Supply
Total FIT’S :
MTBF : 1/186.65= .005
Dominant part for unreliability is the switch with lambda = 44.
Elimination of mechanical switch will reduce considerable the lambda factor.

50. Display Block Owner: Sneha Juvekar
The purpose of the display block is to convert the analog signal from the signal conditioning block to the digital signal and to display either the temperature inside the kegerator in degree Celsius or weight of the tank in pounds on the 7 – segment LEDs and to eliminate the switch bounce caused by user interface.

51. Performance Requirement for Display
User Inputs:
-Input: 0 to 5VDC Analog signal from signal conditioning block and 5 to 6VDC from power supply.
-Indicator Viewing Environment: Bright light.
-Switch Type: SPST (Mechanical) Switch.
-Analog Input Signal Frequency: 67Hz.
-Analog Input Signal Impedance: 800ohms.
-Power Signal Input Frequency: 57 – 63Hz.

52. Performance Requirement for Display
Accuracy:
-Within 1% to 5%
User Indicators:
-Indicator Parameter: 4 7-segment LEDs.
-Binary Indicator Technology: LED.
-Analog Indicator Technology: Filament.
-Numeric Indicator Technology: 7–segment LED.
-Applicable User Interface Type: Analog Switch
-Mechanical Interfaces: PCB

53. Performance Requirement for Display
Operation Modes:
- Applicable Power Input Type:DC.
-Functional Mode: Normal.
-Functional Features: Secure
-Functional Threshold voltage for a CMOS Hysteresis gate: 0.45 to V
Electrical Interfaces:
-Signal Type: Analog.
-Signal Direction: Input.
Mechanical Interfaces:
-Mechanical Interfaces: PCB.
Overall Product Association:
-Required to convert the analog signal into a readable measurement of either Temperature or Weight.

54. Standard Requirement for Display
Max. Material Cost: $149.52
Max. Manufacturing Cost: $22.50
Max. Display Volume: 2.7 cm3
Max. Display Mass: 7lbs.
Total Components required: 17
Total PCB Area:
Input Voltage Requirements: 5 to 6VDC
Input Current Requirements: 200mA.
Max. Total DC Power: 7.5Watts

55. Standard Requirement for Display
Min. Operational Ambient Temperature Range: 0 to 32 degree Celsius.
Min. Operational/Storage Ambient Humidity Range: 100 %Rh.
Min. Storage Ambient Temperature Range: -50 to 65 degree Celsius.
Applicable Safety Standards: UL 873.
Applicable EMC Standards: IEC
Estimated Max. Production Lifetime: 5 years.
Reliability in MTBF: 0.04 years.
Service Strategy: Repair.

56. Standard Requirement for Display
Full Warranty Period: 2 years.
Consumption Power: 7.5 Watts.

57. Safety Requirements for Dispaly
Compliance with IEC
Compliance with IEC
Compliance with IEC
Compliance with IEC
Compliance with MIL-PRF-38535
Compliance with MIL-STD-202
Compliance with UL 1741
Compliance CISPR11- RF Emissions

58. Display: Block interface
Power Signals
Type
Direction
Voltage
Voltage Range
Freq
Freq Range
% V-Reg
V-Ripple
Current
Nominal
Min
Max
Power supply
DC Power
Input 6V 5V
7.5V DC
N/A
0.01
1.8V
1.0A
Analog Signals
Type
Direction
Coupling
Voltage Max
Impedance
Freq Range
Leakage
Amplitude
Min
Max
Signal Conditioner
Analog
Input
Direct
5.0V
800 ohm
1.2Kohm DC
N/A
10pA
800ohms
1.2Kohms

59. Block Breakdown 7 segment LEDs A/D Converter Multiplexer
Input of 5 to 6 VDC from power supply
Input analog signal from signal conditioning block
7 segment LEDs
A/D Converter
Multiplexer
(CMOS Analog Switch)
Mechanical Switch
Hysteresis Buffer
Analog Debounce
User

60. Block Detail Design

61. Block Detail Design
Multiplexer which is the CMOS Analog Switch MAX319 takes the analog input signal from the signal conditioning block and the output of the Switch is connected to A/D converter.
Analog Switch is implemented in order to ensure that the switch bounce stops before the Hysteresis gate reaches its input threshold voltage.
CMOS Hysteresis gate with a threshold voltage of 0.45 to 0.55V in order to pull the input out of the threshold the first time the gate switches.
Mechanical Switch is used to select either the temperature signal or weight signal as an input for the Multiplexer.

62. Block Detail Design
ICL7107 A/D Converter is used to take the analog input signal from the Multiplexer and convert it to digital signal which provides an input digital signal to the 7-segment LEDs.
7-segment LEDs is used to display the temperature and weight measurements in numbers.
3 rightmost LEDs display numbers from 0 to 9 and the leftmost LED can only display number 1 and if the measurement is negative, it displays a “-” sign.

63. Block Detail Design Specifications: Features:
Supply Voltage: +/-5V (Symmetrical)
Power requirements: 200mA (maximum)
Measuring range: +/- 0 – VDC in four ranges.
Accuracy: 1%
Features:
Small size.
Low cost.
Simple adjustment.
Easy to read.
Durable.

64. Reliability Assessment, Growth (Display Block)
Total FITS:
MTBF:
Dominant part for unreliability with highest lamda: switch
Implementing a flip-flop instead of a mechanical and manual switch

65. Load Cell Block Owner: Nick Bouche
The load cell will measure the weight of the keg and its contents. This will then be calibrated such that the weight of the keg will be zero so that only the contents are weighed. This weight will then be converted to volume.

66. Standard Requirements
Compliance with IEC
Compliance with IEC

67. Performance Requirements
Accurate within 0.8 lbs

68. Block to Block Interface for Load Cell

69. Breakdown Diagram Power Force Sensor Zero Calibration
Weight to Volume Converter
To Signal Conditioner

70. Detail Design
Force sensor will be used for measuring weight

71. Solenoid Valve Block Owner: Nick Bouche
The solenoid valve block will dispense liquid per the users’ input. The user must enter in the correct code and then select one of a number of sizes. This block will be responsible to dispense liquid for only as long as needed to pour the correct amount of liquid.

72. Standard Requirements
Compliance with CSA C22.2
Compliance with IEC

73. Performance Requirements
Dispense the amount of liquid wanted using
A known flow rate
A timer
User will select a position on a switch to determine the amount of time the valve will open
User will push a button to open the valve for the select time period

74. Block to Block Interface for Solenoid Valve

75. Breakdown Diagram Size 1 Size 2 Size 3 Password from keyboard
Flow Control
Power
Relay
Solenoid Valve

76. Detailed Design

77. Detailed Desgin
R1 will vary based on the users’ selection of volume of liquid to be dispense.
R1 determines how long the signal will be 5V before dropping to 0V.
R3 acts to create a voltage divider so that the voltage at that point is 5V so that it matches the input signal from the keypad.
The switch that closes the circuit at t=0 will be a momentary N.C. push button.
The output from this circuit will be the input for the relay which will then feed power to the valve.

78. Reliability Assessment, Growth (Solenoid Block)
Total FIT’S : 319.3
MTBF :
Dominant part for unreliability are the relay and the solenoid valve.
A relay and a solenoid valve that would have higher maximum rated voltage would improve the reliability.