Transcript Midterm Design Review

ECE 477 Design Review
Team 07  Fall 2007
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
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Project Overview
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Hand held TV remote
- Can “learn” IR signals from existing remotes and
recreate these signals
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LCD display on device
- Capable of receiving a composite video stream at
2.4GHz and display it on the screen
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Touchscreen interface
- Can take touch input on screen to change channel on
device and change channel on TV
Project Overview
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Runs on rechargeable batteries
The device runs on rechargeable batteries and
has a built-in charging interface to charge the
batteries from a wall wart input
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2.4 GHz video receiver
Receives composite video from a 2.4GHz
transmitter. This transmitter is connected to an
external TV box with remote capabilities.
Project-Specific Success Criteria
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PSSC #1
An ability to decode a Composite video signal
(transmitted via a 2.4 GHz wireless link) and display it
on an LCD touchscreen.
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PSSC #2
An ability to input user commands from
an LCD touchscreen.
Project-Specific Success Criteria
 PSSC #3
An ability to program (“learn”) the IR
modulation scheme used by the user’s
television set and “cable box”.
 PSSC #4
An ability to transmit IR commands
(separately) to a television receiver and to
a “cable box”.
Project-Specific Success Criteria
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PSSC #5
An ability to intelligently recharge the
remote’s battery and monitor its status
(e.g., display a battery fuel gauge).
Block Diagram
Component Selection Rationale
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Microcontroller – PIC24 Series by Microchip
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Processing power: 80 Mhz
On-chip peripherals: SCI, SPI, TIM, ATD, PWM
Cost: $10.70
Low power consumption
Component Selection Rationale
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LCD Module – MTF-T035DHSLP-A by Microtips
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Size and resolution: 3.5” diagonally, 320x240 at 18 bit, 30 fps
Integrated touch panel
Digital input: TFT interface
Cost: $47
Component Selection Rationale
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Touch Screen Controller –
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Serial Interface
Low power consumption:
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ADS7843 by TI
750μW at a 125kHz throughput rate and a 2.7V supply
Under 0.5μW during shutdown mode
Energy Conservation:
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Accurate output on first conversion cycle
Pen Interrupt Request Feature.
Component Selection Rationale
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Wireless Receiver – AWM634RX by Airwave
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Compatibility with NTSC video format
Low power consumption
Operation Frequency Range of 2400 ~ 2483MHz
Cost: $27
Works ideally with sister transmitter (AWM630TX) with cost of $16
Component Selection Rationale
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Battery Charger – DS2715 by Dallas Semiconductor
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Can charge battery packs with anywhere between 1 and 10 batteries
Works with NiMH batteries
Allows use of batteries during charge
Battery Monitor – DS2438 by Dallas Semiconductor
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Simple three pin interface (Positive Lead, Negative Lead and MicroC interface)
Works for NiMH batteries
Designed for battery packs between 2 and 6 batteries
Packaging Design
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Packaging Considerations:
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AA Batteries
 2.01”
Length
 0.56” Diameter
 6 Batteries Total (2 Columns, 3 Rows)
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LCD Screen
 3.5”
Diagonal
IR LEDs
 3 push buttons for power
 Handheld
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Packaging Design
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
Schematic/Theory of Operation
PCB Layout - Considerations
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Placing the power management portion of the PCB at
the lower end to allow easy access to the battery pack
Separate the analog (2.4GHz receiver and ADC) portion
from the digital (LCD, Touch controller, Microcontroller)
portion
Place Receiver on the top left of the device to minimize
noise picked up by the antenna
Place oscillator as close to the ADC as possible
Place bypass capacitors as close to IC’s as possible
Avoiding 90deg traces (using 135deg traces)
Separate grounds for analog and digital circuits
PCB Layout – Component Placement
PCB Layout – Bypass Cap for MicroC
PCB Layout – ADC Oscillator Placement
PCB Layout – Charger Circuit
PCB Layout – Plan of Action
Complete routing (possibly un/reroute) to
better optimize traces
 Add mounting holes to the edges of the
board
 Add RS-232 port for programming MicroC
 Add level translation for RS-232
 Add socket for wall wart input at an edge
 Antenna being wired to header on board
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Software Design/Development Status
Software Design/Development Status
Software Design/Development Status
Project Completion Timeline
Questions / Discussion