Team: Wireless Nothing

1
Team Wireless Nothing
Preliminary Design Review
Team members
Derek Lindberg
Sean McDevitt
Nick Ciocco
Eric Hoffman
Chris Browne
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What is this Device?

• Two-way wireless communication between to
  separate motorcycles.
• One-way wireless CD quality audio streaming from
  a portable devices audio jack.
• Adjustable volume, microphone gain, and channel
  selection.
• Restricted access to broadcasted audio.
• Modular implementation of a wireless
  communication and audio listening device

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High Level Concept
Short range RF
Long Range RF
Short range RF
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Functional Block Diagram - Headset
Microcontroller
Microphone
Headphones
I2C
I2C Bus
DAC Codec
ADC Codec
I2S
I2S
Transceiver
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Transceiver
ADC/DAC OR Transceiver
I2S
Receiving Transceiver
Single Chip Wireless Transceiver (nRF24Z1)
Transceiver

• 2.4 GHz operating frequency
• Low cost
• Low power
• High-fidelity sound (16-bit)
• Channel selection
• Integrated control channel
• 1Mbit/s 4Mbit/s Data Rate
• I2S or S/PDIF Audio Input (16bit)
• SPI or I2C
• Integrated Frequency Hopping Scheme

I2C
Microcontroller
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Antenna Considerations
2.4 GHz Printed Monopole
2.4 GHz Chip Antennas

• Size 23cm x 1.5mm

• Size Tiny lt 1cm2
• Reduced gain from reduced size

2.4 GHz Printed Whip Monopole

• Size 12mm x 20mm

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Functional Block Diagram Headset, DAC/ADC
Microcontroller
Microphone
Headphones
I2C
I2C Bus
DAC Codec
ADC Codec
I2S
I2S
Transceiver
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DAC/ADC
Microphone
Headphones
MP3 Player
Single Chip DAC/ADC I2S Codec

• Convert between analog and I2S
• Low power low cost
• High quality 16 bit sound
• DAC and ADC in single chip for simplicity
• Integrated gain control, volume control and
  speaker drivers if possible
• I2S communication to Transceiver
• I2C control from Microcontroller

Analog
DAC / ADC
I2S
I2C
Microcontroller
Transceiver
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Functional Block Diagram - uC
Microcontroller
Microphone
Headphones
I2C
I2C Bus
DAC Codec
ADC Codec
I2S
I2S
Transceiver
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Microcontroller

• Primary Functions
• Timing
• Control power consumption
• User feedback (tones, battery level)
• Process user input (buttons)
• Microcontroller (MSP430F156)
• Features
• 24kB Flash, 1024B RAM
• Very-low power
• 330uA active
• 1.1uA standby mode
• 12bit DAC
• I2C and SPI interfaces in hardware
• 48 IO pins
• Overkill, but we will never have to worry about
  exceeding code space or having too few IO pins
  during dev.

Microcontroller
I2C
Transceiver(s)
ADC/DAC
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State Diagram Headset
Tx
Packet Tx
Always
Base Station Found
Wake-On-Voice
Init
Base Station Search
Idle
Wait
Packet Received
Wait
Packet Decoded
Rx
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High Level Concept
Short range RF
Long Range RF
Short range RF
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Functional Block Diagram Base Station
Microcontroller

• Serves as a booster for the helmets voice
  communications
• Receives voice from helmet and retransmits with
  larger gain
• Receives voice communication from other
  motorcyclist(s) and transmits them to the helmet
• Given input from helmet, switches between voice
  communication and music

I2C
Base Station to Helmet Transceiver
Base Station to Audio Device Transceiver
I2C/I2S Bus
Base Station to Other motorcyclist Transceiver
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State Diagram Base Station
Remote Tx/Rx
Voice Timeout w/o Audio
Always
Headset Found
Audio Device Present
Init
Headset Search
Idle
Voice Detected
Voice Timeout
Audio Device Present
Wait
Wait
No Audio Present
Local Audio
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High Level Concept
Short range RF
Long Range RF
Short range RF
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Functional Block Diagram - Media Device

• Transmits streaming wireless audio from a
  portable device such as an mp3 player
• Audio is played back in the helmet
• Has a lower priority than voice comm
• Same PCB as Helmet
• (headphone portion left unpopulated)
• Simplifies Design
• Single circuit to debug

Microcontroller
Media Device
Analog
I2C
ADC Codec
I2C Bus
I2S
Transceiver
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State Diagram Media Device
Always
Base Station Found
Audio Levels Present
Init
Base Station Search
Idle
Remote Tx
Wait
Audio Timeout
Wait
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Highly Modular Design
Base Station
Headphone/Mic
Wireless Audio Transmitter
Audio Codec
Tx/Rx
Audio Codec
uC
Tx/Rx
uC
Tx/Rx
uC
Tx/Rx
Tx/Rx
Audio Codec

• Each component is composed of several re-useable
  modules
• We only need to do low-level design and testing
  once

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Division of Labor
Team members Responsibility
Derek Lindberg Hardware layout and assembly, firmware programming
Sean McDevitt Antenna and Transceiver design
Nick Ciocco Transceiver design and PCB layout overview
Eric Hoffman Hardware layout and assembly, firmware programming
Chris Browne Assembly firmware programming, hardware integration
Group Responsibilities

• Documentation, system development, integration,
  system testing, and documentation

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Project Timeline
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Risks and Contingencies
Risks
Prevention

• Unfamiliar Interfaces and Devices
• I2C/S, Transceiver, Codec
• Difficulty controlling codec/transceiver w/ uC
• Limited transmit range / Problems w/ interfering
  devices
• Lead time on components / Availability problems
• Difficulty getting RF link working
• (RF protocol)
• Compliance with FCC regulations

• Help from TAs, Manufacturers, Dev Boards
• Nordic, Texas Instruments
• May be short range for Expo
• Ordering samples far ahead of time
• Use Nordic dev board
• Will ignore them

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Questions ?