Hvac control and Feedback System 0 Group 2 Steve Jones Mathew Arcuri Elroy Ashtian, Jr
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- 3.4.1 Environmental Conditions for Xenarc LCD Monitor
- 3.4.2 Electrical Characteristics
- 3.5.1 Electrical Characteristics
- 3.5.2 Wi-Fi Dongle Design
3.4 LCD ScreenThe chosen LCD touch screen panel is developed by Xenarc Technologies Corporation which will be implemented into our design as the display for the system's user interface for the efficient HVAC control and feedback system. Since this is one of the most expensive components of the design, we chose this screen based on the fact that it provides excellent display resolution and has a compatible connector that can be interfaced with the Beagle board. The sponsors' desire was to keep the idea of a large, touch screen user interface display area as in the first version of the system while keeping the cost down to both stay within our budget and keep the overall cost of the overall system as low as possible. We have chosen to purchase a 7 inch Thin Film Transistor (TFT) LCD Touch screen Monitor with both Digital Visual Interface (DVI) and Audio Video (AV) inputs. The LCD touch screen can be utilized with either the users finger or a pen to provide input into various states of our HVAC control system. On the main home screen of the LCD screen the user will be able to set the desired temperature and relative humidity for in cooling or heating modes by tapping on the radio buttons provided, view the current temperature and relative humidity inside the structure that it is housed, view the current temperature and relative humidity outside where the remote sensor unit is located, and choose between several settings that range from maximum savings to maximum comfort which adjusts the system's tolerance for temperature and relative humidity variation between set points. The model number of the Xenarc touch screen chosen is 706TSA. Table 7 below describes the features associated with the LCD.
Table Important descriptors of the Xenarc LCD panel The key feature of the panel is that it is considered a 5-Wire Touch screen Display. This type of display is the most durable resistive analog that has drift-free operation even when exposed to temperature fluctuation. It's approximated lifespan is 35,000,000 touches versus 1,000,000 touches from 4-wire resistive touch screen displays. Increased optical quality compared to most small scale LCDs allows for high brightness and a sharper display. With greater touch point density, faster response time and increased speed, the 7" Xenarc Touch screen monitor is capable of providing above adequate visualization to this system. The physical specifications of the LCD touch screen matches the basic requirements requested by the sponsors and provides an optimal essential function for the system's success. Since this is the only portion of the system that a potential customer would interact with, the LCD panel must be as pleasing to work with and attractive. The physical specifications for the Xenarc 7 inch LCD are shown in Table 8 below. (Reference 1)
Table Specifications for 7 inch Xenarc LCD Panel 3.4.1 Environmental Conditions for Xenarc LCD MonitorThe resistive touch screen monitor purchased has a few environmental conditions that needed to be kept in mind. They include storage temperature and operating ambient temperature. The operating temperature can withstand a minimum value of -22° Fahrenheit (-30° Celsius) and a maximum value of 185° Fahrenheit (85° Celsius). For the storage temperature's parameter it can be held at the same temperature range as the operating temperature. Table 9 describes the environmental conditions that must be followed when dealing with the Xenarc 7” LCD with touch screen interface. (Reference 1)
Table Environmental conditions when working with Xenarc 7" LCD 3.4.2 Electrical CharacteristicsThe most important specifications that we must follow when dealing with the Xenarc 7” LCD screen are the electrical characteristics. These characteristics include but are not limited to, digital power supply voltage, power supply current, input high threshold voltage, input low threshold voltage, and power consumption. Table 10 shown below describes how much power, and voltage that will be needed to operate the 7” Xenarc LCD Monitor. . (Reference 1)
Table Xenarc Specs 3.5 ARM Microprocessor Board The ARM microprocessor is what helps to drive the Graphical User interface for the LCD display. It is provides the software developer with a simple way to develop a user interface on the Linux operating system on the screen for to satisfy his or her needs without having to do a great deal of low level graphical programming which would increase the chances of system errors and exceptions. The ARM lies on the Beagle board which is essentially the connector piece between the microcontroller and the LCD interface. The microcontroller would not be capable of producing the information and endure the constant interaction with the user and communication with the system modules because it does not have enough processing power. The board is able to boot a working version of Linux onto the screen, allow for applications written in java to run on the system its greater easy than the previous iteration of the project. With the use of an operating system environment, users will have a more dynamic experience then a static one with the bitmap constructed layout in the first version of the HVAC Feedback system. The high level board is required to be programmed separately from the microcontroller and utilize a separate procedure to accomplish this portion of the programming. The ARM microprocessor is even more essential to the overall system than the LCD screen itself. Although the LCD screen is what the user interacts with and is the only part of the system to be seen by the user, the high level board is responsible for making sure the LCD screen performs the tasks expected of it by the user and responds accurately to the user input. The LCD touch screen contains high quality resolution and have at least 16 bit color. The Beagle board has many features that will satisfy the design requirements of our group. The features of the Beagle board are listed below in Table 12:
Table HLCU features 3.5.1 Electrical CharacteristicsThe electrical characteristics of the Beagle board are important and must be taken into consideration for the overall design and stability of the Efficient HVAC Feedback System. These specifications were considered throughout the development of the system and in the final design of the system. The board draws about 5 V DC and 2A. In order for the Beagle board to operate it requires connections for power, communications, panel, and inverter. A DC power supply is used to provides the system with sufficient power so that the board may function efficiently. Supplies that provide additional current than what is specified can be used if additional current is needed for add on accessories. The amount specified is equal to that supplied by a USB port. A voltage of 1.8V is driven through the board in operation to various components. Table 12 shows the DC power supply specifications.
Table DC Power Specs The Beagle board supports RS-232 for serial communication via UART3 is provided by DB9 connector on the Beagle Board for access to an onboard RS232 transceiver. A USB to Serial cable can be plugged directly into the Beagle. A standard male to female straight DB9 cable may also be used. Below is an illustration of this in figure 39. 
Figure HLCU Communication Setup 3.5.2 Wi-Fi Dongle DesignSince the BeagleBoard does not have a Wi-Fi module we had to choose one that was both able to run on Linux due to having driver support for the operating system and up to the latest wireless standards to ensure compatibility with wireless networks. This meant that the card had to comply at least with 802.11G and ideally 802.11G/N. We also wanted a card that did have the ability for WPA encryption and ideally also WPA2 as these are now the recommended encryption schemes for wireless networks. Previous encryption algorithms were insecure. For this task we choose the Belkin F5D7050 v3002 Wi-Fi module. This has been a known compatible module for the Linux operating system, a rare thing for a USB based Wi-Fi module. It also supports 802.11B and 802.11G support with encryption support of WPA. The Dongle will attach to the BeagleBoard via USB. Directory: seniordesign -> sp2011su2011 sp2011su2011 -> Group 5 Spr-Sum 2011 seniordesign -> Senior Design II paper seniordesign -> Remote Touchscreen-Controlled Defense Turret Senior Design Documentation Courtney Mann, Brad Clymer, Szu-yu Huang Group 11 seniordesign -> Flight Performance Data Logging System seniordesign -> Amphibious vehicle seniordesign -> T-100 Watch Dog (Autonomous Security Vehicle) seniordesign -> Ehvac: Wireless Modular Multi-Zone hvac controller Group b javier Arias Ryan Kastovich Genaro Moore Michael Trampler seniordesign -> Table of Contents Executive Summary 2 Download 0.56 Mb. Share with your friends:
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