SuperTeam 12

Brett Dunscomb David HowdenKevin Bedrossian Chris Clary

NEED

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• Develop a simple application that utilizes a sensor and a microcontroller

• Take a user input from sensor to generate visual stimulus

• Custom 8 ball messages• Fun to build!

Motivation

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• Take a 50 year old toy and modernize it. • In an era where kids have tablets and

cell phones in kindergarten, their toys should share similar excitement.

• Keep it recognizable to those that grow up with the original toy.

• An upgraded version of the current toy

Objective

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Design a prototype for a digital version of the popular children’s toy “Magic 8 Ball” originally conceived by Mattel and improve upon it.

Alternatives

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• Current Magic 8 ball uses a plastic icosahedral (20 sided) die to display one of twenty possible messages

• Stuck with the same boring messages• Custom 8 balls cost $2000 for mold http

://www.ginifab.com/gift/custom_magic_8_ball.html

Requirements

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Acknowledge shaking motion to deploy message

Have at least as many messages as are in the original toy

Low power consumption Insure product is easy to use

for all ages

Our Approach

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• Use accelerometer to acknowledge user input (shaking motion)

• Display random messages on LCD screen

• Use familiar “Magic 8 Ball” casing to house system

State Diagram

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Display Mode

Switch mode

Sleep

Pick Message

Display Message

Time delay expiredDouble tap interrupt

Message chosen

Mode selected

Time delay expiredFree fall interrupt

Wait for interrupt

Design

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Motion MessageMicrocontroller DisplayAccelerometer

Power

SPIInterrupts

I2C

DC Voltage 3.3

9 Volt battery

• 3-axis measurement• Two configurable interrupt pins• Multiple low power modes• Capable of threshold detection

while in sleep mode• Vin of 3.3V with 3.3V logic

Accelerometer

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Analog Devices ADXL345 Breakout from Adafruit

Accelerometer

Implementation• I2C bus

communication• Threshold activity

interrupt• Low power state

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Atmega 328p• 8 bit processor• 8 MHz clock• 32K of flash memory• 2K of Ram• TQFP package 32 pins• Inexpensive

Microcontroller

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Display

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Nokia 5110/3310 monochrome LCD from Adafruit

• 84 x 48 pixel count• Backlit• Runs off 3.3 volt• Uses a SPI bus

Display

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Implementation:• Display all 20 original 8 ball messages• Readable in dark rooms• Displays Bitmaps

Power

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Implementation• 9V battery supply• LM 317 voltage regulator

steps down to 3.3V• Low power mode draws

5mA down from 30mA when displaying a message

Implementation

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Implementation

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IP and Prior Work

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• Atmel TWI_MASTER Library• Adafruit Library• Sparkfun Libray• Display code http://pastie.org/1332371• Mattel for the 8 ball shell and idea

Testing

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BREAD BOARD TESTS• Tested power circuit output• Tested random message display• Tested accelerometer output levels

IMPLEMENTATION TESTS• Tested power to components• Tested sleep mode• Tested shake response

Results

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• Initially tried powering the 8 ball with a shake generator but was unable to make it work

• 9V battery with single regulator was able to power all components

• System goes into sleep mode shortly after message is displayed

• System wakes up when shaken• Display was clear and easy to read

Costs

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• Nokia 5110/3310 LCD $ 10.00• ADXL345 Accelerometer $ 19.95• Atmega 328p $ 2.50• Header pins $ 1.25• Board $ 8.00• 8 Ball housing $ 8.00• Resistors, caps, etc $ 7.00• 9V battery $ 2.50

$ 59.20

Lessons Learned

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• Proper time management is important• Setting documentation standards early

and following them throughout is necessary

• Proper communication is key• Have all the surface mount components

ready to go at once, don’t try adding one later

• With access to reflow oven, the breakout board was an unnecessary cost

Contributions

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• Brett Dunscomb: display coding, breadboard testing, and microcontroller pin assignment for display

• Chris Clary: schematic design, passive component setup, and board layout

• David Howden: power system design, power system test and board layout

• Kevin Bedrossian: accelerometer coding, breadboard testing, and microcontroller pin assignment for accelerometer

• Group: documentation, final construction, component research, and implementation testing