Microchip Technology Humidity Sensor PICtail Spécifications

Efficient HVAC / Humidity Control and Feedback System EEL 4914 Group 6 Summer 2010 Cory Glass Derick Holzmacher Andrew Mertens Joshua New

2 unit can be commanded by the finger or a stylus. When purchasing the LCD touch screen it will be composed of a touch sensor,

92 Table 31 Commands expected to be used in order to place buttons and hotspots on the LCD screen 3.5.4 Macro Commands and File Format As well as bi

93 allow a series of commands to be invoked by a single command. The two main advantages of this are to speed up the display and to reduce the spac

94 #define example 1 t “‟0‟” „1‟ „2‟ #end The following command will use the above macro to display the text “Hello” at location x=40,

95 Efficient HVAC Control and Feedback SystemMain Control UnitUser Interface Remote Sensing Unit Bidirectional Communication with LCD Touch Screen

96 transmission. The ZigBee chip then transmits the information to the ZigBee chip on the Main Control Unit. The Main Control Unit is the most comp

97 wireless chip. After considering readings from the sensors, the web server, and LCD user interface; the Main Control Unit must come to a decisio

98 shown below, illustrates the block diagram of the secondary microcontroller which contains the peripheral connection with the different

99 Figure 51 - Typical Relay setup for HVAC Control Systems The LCD touch screen user interface is one of two ways the user can interact with the

100 Section 4: Prototype 4.1 Vendors These vendors serve a special role and purpose in the development of the HVAC control system as well as have a

101 4.1.3 Sensirion Sensirion is an engineering firm that is located in the municipality in the Canton of Zürich, Switzerland. This company consists

3 Figure 1 Residential Energy Use (Permission Pending from National Academy of Sciences) As the cost of energy increases, the need for a low power,

102 you give yourself enough workspace to add more electronic components if necessary. 4) After that the PCB designer must select the numbe

103 Pads are defined as a portion of a pattern on PCB‟s that are selected for the purpose of surface mounting electrical compone

104 - Another aspect about a snap grid is that it will make editing, movement of tracks, and components easier to do because the board wil

105 Characteristic Impedance      Zo = impedance of an infinitely long line (in ohms) R = resistance (in ohms) L = inductance (in H) G

106 main control unit was batteries but our group decided to implement the 24V AC wire into our design, saving the user the hassle of ever

107 In order to transform the input voltage from 24V AC to 3.3V DC several steps must be taken. First, the signal needs to be converted

108 signal, so a capacitor is placed between the rectifier and the regulator in order to further smooth the signal. Once smooth, the signal is now

109 capable of providing current for an extended period of time. The secondary microcontroller draws 200mA max, the Zigbee chip

110 SRS/SRSZ XX VDC S L Model of relay Nominal Coil Voltage Structure Coil sensitivity SRS 03 Sealed type L: 0.36W Table 34 Key Characteristics SRS

111 delivered to the array driver when the I/O pin goes to its “high” state. This range of current is within the range accepted by the arr

4 for the user. A smart HVAC control system would have a diagnostic element that would present the user with the expected problem and a solution fo

112 devices are subjected to. Figure 55 below shows an example of a possible weatherproof housing for the remote sensing unit. 5"8&

113 also be manipulating the temperature at the remote sensing unit to simulate the outdoor temperature. Depending on the temperature change at bot

114 5.1 Explorer 16 Development Board Microchip‟s® Explorer 16 Development board provides a low cost, modular development system for 16-bit

115 Debugging and testing is going to be the Explorer 16 Development board‟s primary function. The 6-wire In-Circuit Debugger (IC

116 The MRF24J40MB PICtail/ PICtail Plus Daughter Board can be plugged into the Explorer 16 Development Board. The 30-pin card edge connecto

117 between the two devices, and the daughter board handles all of those connections as seen the Figure 59 below. Figure 59 MRF24WB0MA

118 5.5 Equipment To observe and test the behavior of our HVAC control system we are going to use the available devices that are presently in the Se

119  Soldering Gun This electric tool is used to solder loose wire connections in a circuit or network. To accompany the gun we must have solder

120 Main Microcontroller Secondary Microcontroller Supply Voltage: 3 – 3.6V Supply Voltage: 1.8 – 3.6V Up to 40 MIPS 4 Kbytes program memory Two 40

121 intelligent decision to satisfy the preset temperature and relative humidity levels in the most effective and energy efficient manner. The sy

5 determine whether or not the outdoor air is suitable to be brought into the building. Another objective of the remote sensing unit

122 The subsystem that controls new air flow into the building is required to control four dampers in the ducts of the HVAC system, and is required

123 between the two settings allows the user to specify to the system how much the conditions must differ from the set conditions before action will

124 component, the Main Control Unit. The Remote Sensing Unit uses a single sensor that is capable of making the temperature an

125 on the display and also reports to the main microcontroller what has been touched on the screen. The display is composed of a home

126 humidity as well as manipulate all other options that are available on the LCD touch screen. Considerations have been made to allow features t

127 Bibliography  Levenhagen, John I. and Donald H. Spethmann. HVAC Controls and Systems. New York, NY: McGraw Hill, 1993.  Heath, S

128 <http://www.sensorsmag.com/sensors/humidity-moisture/choosing-a-humidity-sensor-a-review-three-technologies-840>.  Tennermann, Jim. Th

129  “How Can I Get Started.” Getting Started with Embedded Touch Screens. Reach Technology Inc, 2010. <http://www.reachtech.com/evaluate/how_c

130 Appendix A: Datasheets Explorer 16 Development Board User‟s Guide by Microchip dsPIC33FJXXXGPX06A/X08A/X10A Data Sheet by Microchip PIC24F04KA20

131 Appendix B: Copyright / Permissions Derick We would be glad to let you use 3M images with the proper "Provided courtesy of 3M Touch Syste

6 1.3.3 LCD Touch Screen Display The objective of the LCD touch screen display is to provide the user an intuitive, easy to manipulate means of cont

132 service? Please complete the form below. Required fields are indicated by an asterisk (*). Top of Form *Subject of your message:Asking permiss

133 *Message:I am a Senior at the University of Central Florida in Orlando, Florida. I am in my Senior Design class and our group is building an HVA

134 National Semiconductor Permission: Evervision LCD Permission:

135 Reach Technology Permission:

136 Microchip Permssion:

137 Home > Contact Info Contact Us First Name * Derick Last Name * Holzmacher Title Electrical Engineer Company * University of Central

138 Country * United States Postal Code/Zip * 32765 Comments I am a Senior at the University oI am building an HVAC control sThanks very much.

139 Phone 727-580-6767 Fax E-mail Address [email protected] Sales Manager Action (Select one) Response RequiredCommentary Only Part Number

140

141 Abbreviations and Acronyms AC – Alternating Current ACK – Acknowledgement Frame ADC – Analog to Digital Converter CpE – Computer Engineering CP

7 The system is intended to be able to be retrofitted to an existing HVAC system, and therefore several requirements must be taken into consideratio

8 The system needs to be able to expand for features to be added in the future. Later on the sponsors may want to develop another version of the sy

9 programmer. He is also the only group member with experience in setting up a web server therefore he is best fit for that responsibility as well.

10 Roles and Responsibilities for Senior Design I Paper DerickCoryAndrewJoshuaExecutive SummaryMotivationObjectivesDetailed SpecificationsDetailed R

11 microcontroller has multiple inputs (user settings, indoor temperature and relative humidity conditions, and outdoor temperature and relati

12 will allow us to write the code in the C language which we are all familiar with. This part of the programming determines how the buildi

13 Efficient HVAC Control and Feedback SystemMain Control UnitUser Interface Remote Sensing Unit Bidirectional Communication with LCD Touch Screen

14 Our project was selected during the first meeting with Dr. Richie when he reviewed our “iTemp” project idea and asked us if

15 cited and the necessary steps have been taken to avoid copyright infringement, and to get the document printed, bound, and ready to han

16 Figure 5 Meeting Timeline The other type of event in Figure 5 above is sponsor meetings. These do not have a set schedule, but happen when the

17 The sponsor will order all of the parts and have them shipped to their place of residence. In order to provide the sponsor with the list of part

18 Section 2: Research 2.1 Research Methods Our group came together and met generally for 2 days every week and would distribute and assign the

19 For the design section of the report we focused our research on the specific parts we chose for the Efficient HVAC Control and Feedback System.

20 microcontroller to ensure we develop the main microcontroller to operate to their exact specifications. The performance of the main micr

21 main microcontroller to communicate with the other components of the main control unit. In addition to these components, the

i Table of Contents Section 1: Introduction / Definition ...

22 The MPLAB Integrated Development Environment and the MPLAB C30 C Compiler are ideal for our project because it allows us to p

23 from the same manufacturer we are able to use the same development board to program multiple devices. Voltage and current requirements: The sou

24 understandable form that the user will be able to comprehend. The microcontroller has 256 Kbytes Flash Memory which will hold our pro

25 The I2C protocol will be used to interface the main microcontroller to the temperature and relative humidity sensor. The microcontro

26 the dsPIC33FJ256GP710A. The cost of the microcontroller itself is a very small percentage of our overall costs, but we kept in mind that should t

27 Pin Name Pin Type Pin Description AVDD Power Positive supply for analog modules. AVSS Power Ground reference for analog modules VDD Power Positiv

28 The main microcontroller shares the main control unit with two devices requiring SPI connections, one device requiring an I2C connection,

29 output rating. This component is not included in the following diagram, but will be discussed in detail in the relays section of this paper. Fi

30 2.3 Secondary Microcontroller For the secondary microcontroller for the system, we needed a simple and very low power consuming component. This s

31  4 Kbytes Flash Program Memory for storing and executing application code  512 Bytes RAM data memory The microcontroller is also cap

ii 2.7.1 Remote Access ... 45 2.7.2 TCP/IP ..

32 BatterySecondary MicrocontrollerSHT21Temperature and Relative Humidity SensorPIC24F04KA201 Secondary MicrocontrollerMRF24J40MBZigBee Wireless Tra

33 Some important factors when choosing the best relay to purchase for the HVAC control system are:  Affordability, whether it is cost effic

34 Figure 10 Typical HVAC relay setup Researching different types of relays led us to come across the website: http://www.deltrol-contro

35 the relay receives the correct current and voltage. Another option for this step is to use a relay driver which is a surface mount chip with sev

36 The surface acoustic wave technology features two transducers so that when the panel is touched it can find the coordinate accordingly. These t

37 Figure 13 Capacitive touch screen (Reprinting Permission Requested from 3M Touch) To differentiate all three different varieties of touch screen

38 last?) 5 years for 5 Wire Cost Inexpensive Expensive Average cost Sensitivity Very sensitive to scratch Sensitive to scratch Sensitive to dirt Ad

39 driver will permit the touch screen and the computer to work together. The most commonly used touch screen driver is the mouse-emulation

40 2.6.1 Ethernet and Wireless Routers Ethernet is a branch of wired technologies under the Local Area Network communication. Ethernet‟s

41 relays controlling the different heating and cooling options so that the appropriate action can be carried out. The question becomes which form o

iii 3.4.2 Electrical Characteristics ... 86 3.5 SLCD5 Control

42 Pros Cons Transmission range between 10 – 75 meters (33 -264 feet) and up to 1500 meters for ZigBee pro On the cluttered 2.4 GHz ISM band Maximum

43 transmit approximately 10m and Class 3 uses up to 1mW of power and can transmit approximately 1m. Like any protocol, there are dr

44 (Mbps), which is overkill for our system. By adjusting throughput to 1 Mbps, we can extend the indoor range from 30 meters, to 90 meters, which i

45 the main microcontroller through the ZigBee method, it too must have some basic requirements, which are also listed below in Table 9.

46 This means there is a huge market for applications to allow consumers to access and manipulate their home or office appliances and HVAC systems w

47 2.7.4 Internet Layer The Internet layer helps define how interconnected networks function. This layer is the lowest layer concerned with devices

48 2.7.6 Application Layer The application layer is that which network applications operate at. Applications that operate at this layer are,

49 TCP/IP Stack uses a multitasking technique called cooperative multitasking. In a cooperative multitasking system, there is more than one task; e

50 MPFS_WRITE_PAGE_SIZE(mpfs.h) 1-255 To define writable page size for current MPFS storage media Table 11 Configuration used by MPFS.C StackTsk.c

51 not required. This module will be automatically enabled if there is at least one high-level module requiring TCP. Table 13 Configuration used by

iv Table of Figures Figure 1 Residential Energy Use ... 3 Figure 2

52 UDP applications Table 15 Configuration used by UDP.c MAC.c handles the Media Access Control operations. This allows for the emulatio

53 MAX_HTTP_ARGS (HTTP.c) 1-31 To define maximum number of HTML form fields including HTML form name MAX_HTML_CMD_LEN (HTTP.c) 1-128 To define maxim

54 Figure 16 Mandatory programming sentences The provided TCP/IP stack is specifically written to utilize the Realtek RTL8019AS Network

55 that the same message can be retransmitted, if required. The size of this buffer can be specified. 2.7.9 Microchip HTTP Server With Microchip‟s

56 Figure 17 Uploading an MPFS Image using FTP To provide the user with a dynamic page in order to view current system data, the use of CGI will be

57 Possible values for this parameter are: Value Meaning HTTP_START_OF_VAR This is the very first callback for given variable for the current insta

58 During processing of this file, HTTP encounters the „%04‟ string. After parsing it, HTTP makes a callback. HTTPGetVar(4, HTTP_START_OF_VAR, &am

59 Figure 21 MPFS Image Format The length of the Reserved Block is defined by MPFS_RESERVE_BLOCK. This block can be used by the main application

60 block. All file names are stored in upper case to make file name comparisons easier. Each FAT entry points turn to a data block that contains t

61 2.11 Scripting Languages 2.11.1 PHP PHP is a widely used, general-purpose scripting language. It was originally designed for web deve

v Figure 39 SHT21 Normal operating range ...82 Figure 40 SHT21 pin layout ...

62 2.12 Power 2.12.1 Main Control Unit / LCD Touch Screen User Interface The main control unit and LCD touch screen user interface are to

63 2.13 Batteries Batteries are going to be used to store capacitive charge in the secondary microcontroller for the HVAC control system

64 These batteries on average contain a voltage of 1.2 V, a specific energy of approximately 70 W*h/kg, and an energy density of 300 W*

65 electricity mains. A brownout occurs when there is a decrease in voltage from an electrical power supply. Both of these conditions have serious

66 When using the manual air control timer mode: Door 1 (damper 1) is open, door 2 (damper 2) is closed and door 3 (damper 3) is open.

67 handle on the outside of a duct. Depicted below in Figure 25 is an example of what manual balancing damper looks like. 18"18" Figure 2

68 In order to purchase HVAC automated zone dampers there are some questions that must be considered before a purchase is made. Pick an

69 commercial units, vehicles as a digital or analog display, and thermometers (to read a person‟s internal temperature or for instance; to read the

70 2" Figure 28 Bead type thermistor ((Permission is granted under the GNU Free Documentation License, http://en.wikipedia.org/) Different temp

71 efficient or cost - effective the sensor is. If all these conditions are met, then the customer is on the right track in purchasing a sensor. An

vi Table 21 Configuration used by SLIP.c...53 Table 22 Features of MRF24J40MB

72 Figure 30 Output Signal in mV vs. Absolute Humidity in g/M3 for Thermal Conductivity sensors (Reprinting Permission Requested from Questex Media

73 whether the sensor is weather proof or resistant, cost - effectiveness, size, and maintainability. Relative humidity is an important conce

74      where Tc = temperature in degrees Celsius. The vapor pressure of the air is also found according to the

75 UserPower RelaysAdjust ComfortSettingsAdjust VentingSystemAdjust SettingsAdjust PowerSettings«extends»«extends»Get Sensor ReadingsProcess HVACCon

76 Key Features of the MRF24J40MB Operates on ISM Band 2.405 – 2.475 GHz freq. Small size: 22.9 mm x 33.0 mm Supports ZigBee®, MiWi and MiWi P2p

77 clock (SCK), while the data will exchange through the SPI data in and out (SDI, SDO) pins. All data communications with the module are

78 Digital I/O Input High Voltage (VIH) 0.5 x VDD ______ VDD + 0.3 V Input Low Voltage (VIL) -0.3 ______ 0.22 x VDD V Table 23 MRF24J40MB Recommende

79 The main block diagram for the MRF24WB0MA module is shown in Figure 36 below. This diagram depicts the main connections between the

80 The MRF24WB0MA has several power states. These are Hibernate, Sleep, and Active, which has two sub-states. The power state diagram in t

81 Figure 38 MRF24WB0MA Power State diagram (Reprinted with permission from MicroChip®) 3.3 Temperature and Relative Humidity Sensor In order to

1 Section 1: Introduction / Definition 1.1 Executive Summary Electrical Engineering is a diverse field with applications that affect everyone in the

82 Figure 39 SHT21 Normal operating range (Reprinted with permission from Sensirion) The SHT21 has a default resolution of 12 bits for relative hum

83 Data can be transmitted across the SDA line only after a “start condition” has been met. The start condition entails the SDA line g

84 sensor without having to turn off the power. The soft reset function takes less than 15ms. The user register is an eight bit register that comes

85 TFT-LCD panel, and the SLCD5 controller (SLCD5 controller will be discussed in detail in a later section). To activate the LCD touch screen we ca

86 3.4.1 Environmental Conditions for Evervision LCD Panel Our resistive touch screen device we purchased has many environmental conditions

87 3.5 SLCD5 Controller The SLCD5 controller is what provides the GUI for the LCD interface. It is meant to give the developer a simple way to gene

88 Features of SLCD5 Drives digital TFT displays at QVGA and VGA resolution Beeper for audible touch feedback and alarms 16 bit color 3” by 4.5”

89 SLCD5. 4.5"3.0" Figure 45 Connectors and Jumpers Layout of the SLCD5 (Reprinted with permission from Reach Technologies Inc) The SLCD5

90 3.5.2 Touch Interface The touch controller of the SLCD5 is meant to interface to a four wire resistive touchscreen. Touch sensitive areas o

91 be in 24 bit RGB color. The SLCD5 uses 16 bit color in 565 formatting, but the BMPload program does the required translation. The BMPlo