GROBIGizmo Remote Operated Bluetooth

Interface

Sponsor: Calit2

Mentors: Paul Blair & Javier Rodriguez MolinaTeam: Kristi Tsukida & Eldridge Alcantara

Group 13ECE 191 Fall 2006 – Week 8

November 16, 2006

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jectAgenda

• Gantt Chart• Tasks Performed• Technical Content

– Bluetooth Status Detection– GIZMO User Interface– Motor Control Settings– Successive Approximation ADC

• Summary

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Gantt Chart

TASKS DURATION WK

1 WK

2 WK

3 WK

4 WK

5 WK 6

WK 7

WK 8

WK 9

WK 10

WK 11

Research -Hardware: Atmel, servo, accelerometer -Order parts: microcontroller, accelerometer

1 week

Design 1st Prototype (PC->AVR->Motor) -program microcontroller -integrate hardware components

3 weeks

Develop custom circuit -include microcontroller, Bluetooth, accelerometer -install on GIZMO truck

3 weeks

Design 2nd Prototype (Phone->AVR->GIZMO) -create phone software -program microcontroller

5 weeks

Optimize and add additional features 4 weeks Final Report 2 weeks Documentation 11 weeks

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Tasks Performed

• Sent commands from cell phone to GIZMO truck (Eldridge)

• Finished final circuit board design (Kristi)

• Wrote code to handle when Bluetooth is disconnected (Kristi)

• Wrote ADC code to read and process data from accelerometer (Eldridge)

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Block Diagram of Final Prototype

References:1 - http://nds2.photos.nokia.com/EUROPE_NOKIA_COM_3/r2/press/photo/phones/jpeg/05_6600_lores.jpg2 - http://www.ixbt.com/mainboard/images/barebones-2k3-may/pundit/pundit-bluetooth-module.jpg3 - http://www.roboter-teile.de/Shop/images/dbimages/artikel_0000017_s.jpg4 – http://memsic.com5 - http://responshphere.calit2.net/gizmo

Bluetooth Serial Adapter

Microcontroller

Accelerometer

Cell Phone

Circuit Board

GIZMO

12

3

4

5

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Tasks Left To Complete

References:1 - http://nds2.photos.nokia.com/EUROPE_NOKIA_COM_3/r2/press/photo/phones/jpeg/05_6600_lores.jpg2 - http://www.ixbt.com/mainboard/images/barebones-2k3-may/pundit/pundit-bluetooth-module.jpg3 - http://www.roboter-teile.de/Shop/images/dbimages/artikel_0000017_s.jpg4 – http://memsic.com5 - http://responshphere.calit2.net/gizmo

Bluetooth Serial Adapter

Microcontroller

Accelerometer

Cell Phone

Circuit Board

GIZMO

12

3

4

5

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Bluetooth Status Detection

• Detect Bluetooth disconnection– Stop truck when disconnected

• Bluetooth module has status pin which is low when disconnected

• Use microcontroller pin change interrupt to detect a high low transition

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GIZMO Remote Control User InterfaceVersion 2.0

Divided “Command” section into two parts

Added a section to display velocity

F

L S R

B L S R

F

B

Joystick

Keypad

CommandsL = LeftR = RightF = ForwardS = StopB = Backward

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Motor Control Settings• Settings modifiable

from phone menu• Different for different

ESC (electric speed controller) and motors

• Save settings to EEPROM of microcontroller

PW

M p

uls

e w

idth

SpeedLevel = 0

Speed level = 1 Speed level = 2

Max speed level

SpeedLevel = ...

Init speedBase speed

Forward Increment

Init time

time

Example: Modifiable settings for a forward PWM signal

high pulse needed to get truck tostart moving

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Block Diagram forADC and Accelerometer

Cell Phone

Accelerometer

Atmega164P

ADC DetermineAcceleration

TransmitBuffer

Bluetooth

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Successive Approximation ADC

End of ConversionSuccessive

Approximation Register

Digital toAnalog Converter

Sample andHold Circuit

http://en.wikipedia.org/wiki/Successive_Approximation_ADC

Output of ADC:

)12( N

Vref

Vin

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Successive Approximation ADC

1 0 0 0

1 1 0 0

1 0 1 0

1 0 1 1

1 0 1 1

8

12

10

11

11

DAC Output = 1.067 < Vin

DAC Output = 1.6 > Vin

DAC Output = 1.35 < Vin

DAC Output = 1.467 < Vin

Let ADC have 4 bits of precision

Let: Vref = 2 V Vin = 1.5 V

From formula:

11)12( 4 Vref

Vin

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• Current state: we can control the GIZMO truck through cell phone

• Plans for next two weeks: - send accelerometer data to cell phone (Eldridge) - install circuit board on GIZMO truck (Kristi) - motor control settings on microcontroller (Kristi) - motor control settings on phone (Eldridge) - optimize microcontroller code (both)