ECE 477 Design Review Group 3  Fall 2005

Outline Project overview Project-specific success criteria Block diagram Component selection rationale Packaging design Schematic and theory of operation PCB layout Software design/development status Project completion timeline Questions / discussion

Project Overview P.E.T. Express will use RF-ID technology to control access through a common pet door. The P.E.T. Express will utilize a Motorola MC9S12NE64 and will include feedback ability through an LCD display, embedded web server, and keypad input. These features, along with software controlled permissions, will control the locking action of the pet door through the use of pulling solenoids.

Project-Specific Success Criteria Ability to unlock pet door in response to RFID tag detection or manual override pushbutton. Ability to configure pet door and monitor its status via an embedded web server. Ability to provide audio feedback ("beep") in response to RFID tag detection. Ability to display pet door status locally on an LCD (suggest using RPG to scroll/select). Ability to continue operation in the event of A.C. power failure (battery backup).

Block Diagram

Component Selection Rationale Microcontroller – MC9HS12NE64 (112 pin) Adequate RAM and FLASH 2 SCI ports, Embedded Ethernet, Timer module Prior knowledge of product and available support LCD – Crystalfontz CFA-634 SCI output 4x20 character display RFID - Intersoft WM-RO-MR2 SCI output, customizable antennae Adequate transmission range (~10”)

Component Selection Rationale Keypad and Encoder – Allelectronics KP-23 & Fairchild MM74C922 Adequate functionality (16 keys) Reasonable encoding (4 bits) Solenoid – Allelectronics SOL-58 Adequate range of motion Adequate pulling force Spring return Power Supply - PST-AC0407 120 W Adjustable Output Adjustable output voltages Adequate current rating (6.8 A) Battery - 12V / 7Ah Sealed Lead Acid Battery Adequate voltage and current supply Able to be charged easily

Packaging Design P.E.T. Express will consist of two main sections: a pet door and a control module. The pet door will house the solenoids and the RF-ID antenna will wrap around it. The power and control lines for the solenoids and the antenna lead will run from the control module to the pet door. The control module will house the PCB, external circuitry, and all the associated peripheral devices. A power cord from the wall and control lines out will attach to the outside. It will be of an appropriate size to mount to a normal door.

Schematic/Theory of Operation Power System Overview 18V Input Supply – Supply Voltage from AC switching power supply. 15V Linear Regulator – Converts 18V to 15V using LM317; Used for battery charging circuit and solenoid power. 9.6V Linear Regulator – Converts 15V to 9.6V using LM317; Used as input to RF Reader. 5V Switching Regulator – Converts 15V to 5V using LT1076; Used as input to LCD, RS232 level translator, speaker, and solenoid driver circuits. 3.3V Step-Down Regulator – Converts 5V to 3.3V using LTC1174; Used as input to the microcontroller, keypad encoder and Ethernet transformer. 18V Input Supply 15V Regulator 9.6V Regulator 5V Regulator 3.3V Regulator

Schematic/Theory of Operation 15V Linear Voltage Regulator Incorporates a fuse Overload protection circuitry Battery trickle charger Dual voltage bus depending on operating mode

Schematic/Theory of Operation 9.6V Linear Voltage Regulator 15V input Overload protection circuitry

Schematic/Theory of Operation 5V Switching Voltage Regulator Switching voltage regulator High current output Resistant to input voltage variation

Schematic/Theory of Operation 3.3V Power Supply Regulator 5V input voltage Overload protection circuitry

Schematic/Theory of Operation Microcontroller 112 pin package Controls all peripherals 64K RAM available

Schematic/Theory of Operation Ethernet Controller Transforms Ethernet signal for transmission Capable of full duplex operation Contains LEDs for visual feedback verification

Schematic/Theory of Operation RF-ID Reader Onboard tunable antenna connection Signal receive interrupt 1ms delay before half-duplex RS232 transmission Operating range of ~10 inches

Schematic/Theory of Operation LCD 4x20 character display Separate LED backlight turn-on Half-duplex RS232 communication

Schematic/Theory of Operation Keypad Circuitry Versatile 16 key keypad 4-bit coder to reduce I/O pin usage Data-Available interrupt pin

Schematic/Theory of Operation

Schematic/Theory of Operation The RF-ID reader will send an interrupt to the microcontroller when a tag comes into range that will enable the SCI port for transmission via RS232 connectivity. The microcontroller compares the received transmission with a set of permissions previously entered through either the keypad or the embedded web server by the user. If the permissions are recognized as admissible, the microcontroller will output a signal to the solenoid driver circuit which will engage the solenoids, thus unlocking the door. Information about system settings can be viewed either on the LCD using the keypad to navigate or by accessing the embedded web server using a PC.

PCB Layout Design Considerations Separate digital and analog grounds Make ground loops as short as possible Similar circuits were placed closely together for clarity and ease of routing. Increased trace size for power supplies and larger current supply and ground buses Decoupling capacitors were used for the larger IC devices such as the microcontroller.

PCB Layout

PCB Layout Power MOS Circuitry Optoisolators 3.3V Power Regulator 5V Regulator

PCB Power Regulators 9.8V Regulator and 15V Regulator

Microcontroller

PCB Layout Keypad Encoder

PCB Layout DB9 Connectors at edge of board

Software Design/Development Status On power-up, the microcontroller will enter a startup code section which will initialize the device, performs a debug sequence, set defaults, and load the web server. Next, it will enter a continuing loop which will poll the possible interrupts of the system: keypad, RF-ID, and Ethernet controller. When one of these interrupts is asserted, the software will address it accordingly. Additionally, there will be setup menus for entering permission information and an online engineering mode to check ports, SCI, web server, and other modules. The software will cause the microcontroller to enter power down mode if an interrupt is not received in a certain time and will be resumed on assertion of aforementioned interrupts.

Project Completion Timeline Week of: Primary Task Secondary Task Oct 10-Oct 16 Design Review Revisions Preliminary Coding Modules Oct 17-Oct 23 Code Module Testing Oct 24-Oct 30 Patent Liability Analysis Hardware and Software Development Oct 31-Nov 6 Reliability Analysis Nov 7-Nov 13 Software Design Considerations, Narrative, and Documentation Report Preliminary Debugging Nov 14-Nov 20 Social and Environmental Analysis Debugging Nov 21-Nov 27 Debugging and Assembly User Manual Development Nov 28-Dec 4 Final Report and Video Dec 5-Dec 11 Poster and Senior Design Report Dec 12-Dec 14

Questions / Discussion