Team: Wireless Nothing

Preliminary Design Review Handmade by Robots

ECEN 4610 Spring 2006Hands-Free Low-Profile Wireless Radio

Team members

Derek Lindberg

Sean McDevitt

Nick CioccoEric Hoffman

Chris Browne

Team: Wireless Nothing

Preliminary Design Review



• Two-way wireless communication between to separate motorcycles.

• One-way wireless CD quality audio streaming from a portable device’s audio jack.

• Adjustable volume, microphone gain, and channel selection.

• Restricted access to broadcasted audio.• Modular implementation of a wireless

communication and audio listening device

What is this Device?



High Level Concept

Short range RF

Short range RF

Long Range RF



DAC CodecADC Codec

MicrocontrollerMicrophone Headphones

Transceiver

Functional Block Diagram - Headset

I2C

I2S I2S

I2C Bus



ADC/DAC – OR – Transceiver

Transceiver Single Chip Wireless Transceiver (nRF24Z1)• 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

——I2S——

——I2C——

Microcontroller

Receiving Transceiver

Transceiver



• Size ~ 23cm x 1.5mm2.4 GHz Printed Monopole

• Size ~ 12mm x 20mm2.4 GHz Printed Whip Monopole

2.4 GHz Chip Antennas• Size ~ Tiny < 1cm2

• Reduced gain from reduced size

Antenna Considerations



DAC CodecADC Codec


Transceiver

Functional Block Diagram – Headset, DAC/ADC

I2C

I2S I2S

I2C Bus



Microphone

Microcontroller

Headphones MP3 Player

DAC / ADC

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

——I2S——

Transceiver

——I2C——

——Analog——

DAC/ADC



DAC CodecADC Codec


Transceiver

Functional Block Diagram - uC

I2C

I2S I2S

I2C Bus



Transceiver(s)

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.

——I2C——

ADC/DAC

Microcontroller



State Diagram – Headset

Init Base StationSearch Idle

Rx

Tx

Always Pack

et Tx

Base Station Found

Wait Wait

Packet DecodedPacket Received

Wak

e-On

-Voi

ce



High Level Concept

Short range RF

Short range RF

Long Range RF



Functional Block Diagram – Base Station

Microcontroller

Base Station toOther motorcyclist

Transceiver

I2C

I2C/I2S Bus

Base Station toAudio DeviceTransceiver

Base Stationto Helmet

Transceiver

• Serves as a booster for the helmet’s 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



State Diagram – Base Station

Init HeadsetSearch Idle

Local Audio

RemoteTx/Rx

Voice Tim

eoutVoi

ce D

etec

ted

Always Voice T

imeo

ut w

/o

Audio

Headset Found

Wait Wait No Audio PresentAudio Device

Present

Audi

o De

vice

Pr

esen

t



High Level Concept

Short range RF

Short range RF

Long Range RF



Functional Block Diagram - Media Device

ADC Codec

MicrocontrollerMedia Device

Transceiver

AnalogI2C

I2S

I2C Bus

• 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



State Diagram – Media Device

Init Base StationSearch Idle Remote

Tx

Always

Audio Timeout

Base Station Found

Wait Wait

Audio Levels Present



Highly Modular Design

uC

Audio Codec

Audio Codec

uC

Tx/Rx

Tx/RxTx/Rx

Tx/Rx

uC

Tx/Rx

Audio Codec

Base Station Headphone/MicWireless Audio Transmitter

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



Division of Labor

Group Responsibilities• Documentation, system development, integration, system testing, and

documentation

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



Project Timeline



Risks and Contingencies

Risks• 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

Prevention• 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



Questions ?

Date post:	11-Feb-2016
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Team: Wireless Nothing

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