1. Group 18 Lucas Chokanis Daniel Ramirez Lloyd Harrison Philip Teten

2.  A Proposal from Researchers to Implement Their Algorithms  Design an Experimental Thermostat to Control a Vehicle’s Heating, Ventilation, and Air Conditioning (HVAC) Systems  Provide a Control System that is Feasible to adapt for Future Modifications

3.  Ability to Detect Input: ◦ Temperature of the Vehicles Interior ◦ Temperature of the Blower Motor ◦ Extra Temperature Sensor for Researchers Use  Control Output: ◦ Speed of the Blower Motor (High, Med, & Low) ◦ Speed Command of the PMSM Motor ◦ Condenser Fan ◦ Clutch Control  Implement a User Interface ◦ LCD Screen and LED’s for Feedback ◦ Push Buttons for User Control

4.  Electrically Noisy Environment: ◦ Use of Parts that Meet Automotive Requirements  15 ft Transmission Lines: ◦ PMSM Motor Control ◦ Two Remote Temperature Sensors  Highly Intuitive Programming: ◦ Giving Researchers Ease of Understanding ◦ Communicating Multiple Temperature Readings Via SPI Bus

5.  Voltage Received: ◦ 12 to 15 VDC  Output to Motors: ◦ 12 VDC Three Speed Blower Motor Control  High, Medium, Low ◦ 12 VDC Condenser Fan ◦ 12 VDC Clutch Control ◦ Linear 0 to 2.63 VDC “Step” Speed Command  Relays: ◦ Four 15 Amp Relays ◦ One 30 Amp Relay ◦ Coil Voltage of 12 VDC  Microcontroller ◦ MSP430 or C2000

8. ParametricsMSP430F2274-Q1TMS320F28030LM4F110B2QR Architecture16-bit32-bit Flash (KB)32 Frequency (MHZ)166080 RAM (KB)112 GPIO324443 I2C114 UART118 SPI/SSI124 ADC10-Bit/12 channels12-bit/16 channels12-bit/12 channels RatingAutomotiveStandard

9. The chosen microcontroller is the MSP430F2274-Q1 for the following reasons:  Ultra-Low power  Code Composer Studio IDE  Qualified for Automotive Applications  Sponsor provided the MSP430 Target board and USB programmer

11.  Ambient temperature Sensor: ◦ Housed on main thermostat circuit board. ◦ Provides feedback to the user via LCD screen  Blower Motor Temperature Sensor: ◦ Remote sensor location. ◦ 15ft away from main board as required by the customer. Its purpose is to keep track of the rate at which the blower motor is cooling.  Auxiliary Temperature Sensor: ◦ Remote sensor location (<15ft away from main board).

12. ModelManufacturerAccuracy Temp. Range Current Draw OutputPrice $ LM35A Texas Instruments ±0.25ºC -40ºC to 110ºC 60µA Linear Voltage 5.60 LM35CA Texas Instruments ±0.25ºC -40ºC to 110ºC 60µA Linear Voltage 14.61 ADT7420 Analog Devices ±0.25ºC -40ºC to 125ºC 265µA 16-Bit 4.87 ADT7320 Analog Devices ±0.25ºC -40ºC to 125ºC 265µA 16-Bit SPI 4.87 ADT7310Analog Devices ±0.50ºC-40ºC to 125ºC 265µA 16-Bit SPI 4.87 TMP100Texas Instruments ±3ºC-55ºC to 125ºC 45µA2.15

13. The chosen temperature sensors were the ADT7320 for the following reasons:  Very high accuracy rating on a wide temperature scale.  We can expect reliable temperature readings in a cold environment such as the evaporator.  User programmable with multiple features  Temperature resolution up to 16-bits.

15.  Extending The SPI Bus for Long Distance Communication: ◦ For the remote sensors, it is possible that propagation delay could be significant enough to hinder data transmission. ◦ Once we attempt to conduct SPI communications at distances greater than 15 feet, we will know if propagation delay will require a hardware solution. ◦ If this turns out to be the case, dual differential transceivers will be used to refresh the clock signal protect the data transfer from noise. ◦ If the signal is fed back to the master from the slave, data transmissions between the master and slave will occur at the same delayed clock signal.

17.  Although the ADT7320 sensor performed above our expectations, we realized that an initialization subroutine was required for it to function reliably.

20.  4 Digits 1 Decimal Accuracy

21.  Driver Uses Less Pin Outs  Good for Intuitive Programming B3B2B1B0LCD Display 00000 00011 00102 00113 01004 01015 01106 01117 10008 10019 1010- 1011E 1100H 1101L 1110P 1111(blank) D1D2D3D4Function 0000No Change 0001Store Data in Latch 4 to be Displayed in Digit 4 0010Store Data in Latch 3 to be Displayed in Digit 3 0100Store Data in Latch 2 to be Displayed in Digit 2 1000Store Data in Latch 1 to be Displayed in Digit 1 1111Store Data in All Data Latches, Display All

23.  View Changing: Scroll Through

24.  Temperature Set for Nominal Setting

25.  Setting the Blower Motor State

30. Solid-State Relays (SSRs) Vs. Electromechanical Relays: Relay TypeProsCons Solid-state  Faster switching times  Increased lifetime (no moving parts)  Bounceless switching  No sparking or arcing  Silent operation  Higher ON resistance (more power dissipated)  Small OFF resistance (small reverse leakage current)  Fails “short” Electromechanical  Lower ON resistance (ohmic contacts)  Higher OFF resistance (no current flow)  Fails “open”  Noisy  Shorter lifetime (10^5 to 10^7 switching cycles)  Switch bouncing  Arcing across contacts

31. Motor Control: Choosing Relay Current Rating DC Supply Voltage (V) LO-speed Current (A) MED-speed Current (A) HI-speed Current (A) 12.05.78.615.0 12.55.98.915.6 13.06.29.016.1 13.56.49.316.9 14.06.69.517.4 14.56.89.818.0 15.07.19.918.7 Blower motor current draw (low, medium, and high speeds) Note: Highlighted values are interpolated values due to limitations in test equipment.

32. Motor Control: Choosing Relay Current Rating Condenser Fan Motor Current Draw DC Supply Voltage (V) Motor Current (A) 12.07.0 12.57.5 13.07.9 13.58.2 14.08.7 14.59.1 15.09.4 Note: Highlighted values are interpolated values due to limitations in test equipment.

34. P/S section:3.3V5V Items Drawing Current 6.5 mA – MCU50 uA – LCD driver 795 uA – Temperature sensors (3 x 265uA) Total per section:7.3 mA50 uA Design current limit: 10 mA1 mA P/S efficiency:91 %84 % Current Draw

35. 3.3V P/S EFFICIENCY 5V P/S EFFICIENCY

36. Load Supply Voltage (V) Supply Current (mA) 3.3V Output Current (mA) 5V Output Current (mA)Efficiency (%) Minimum121311.39.7755.2 151211.39.8348.0 Medium121112.26.3954.7 151012.26.3948.1 Maximum12 12.86.8153.0 151112.86.8146.2 Regulator Efficiency

43. Item PriceQuantitiyPaidTotal Microcontroller - MSP430F2274-Q1 Free Sample1Yes- Temperature Sensors - ADT7320 $ 4.873Yes $ 14.61 PCB by PCBFabrication.com $ 76.006Yes $ 457.00 LCD Display - Lumex LCD Free Sample1Yes- LED for User Interface Owned8Yes- Push Buttons for User Interface $ 0.195Yes $ 0.95 Dual Differential Driver - DS90LV027AQMA Free Sample2Yes- Dual Differential Receiver - DS90LV028AQMA Free Sample2Yes- Shielded Twisted Pair - C1352-100-ND $ 66.961Yes $ 66.96 NPN transistor 200mA ICmax, 40V Vce(breakdown), through hole $0.1710 Yes $ 1.74 Switching Regulator - TI LM26003 Free Sample3 Yes - Relay automotive SPST 12V, 15A$1.796Yes $ 10.74 Relay automotive SPST 12V, 30A$5.022Yes $ 10.04 Capacitors $2.5065 Yes $ 17.47 Diode, Schottky 40V 30mA, through hole $0.665 Yes $ 3.30 Inductor 1mH, 10% through hole $2.793 Yes $ 8.37 Resistors $0.7277 Yes $ 6.79 TSSOP-20 to DIP-20 SMT Adapter (for TI LM26003 chip) $4.492 Yes $ 8.98 TOTAL $ 606.86