Interactive Dynamic Sculpture

Western Washington University

Odin Ringsred

2012/2013

Introduction:

The Interactive Dynamic Sculpture gives observers and users the ability to alter statue shapes in a variety of ways, with relative ease. Users will be able to control the sculpture’s shape with audio signals, preset patterns, custom signal inputs, and manually with an audio equalizer. With the addition of a user interface, this dynamic sculpture will be a truly interactive learning experience for both the user and observers.

Hardware and Dimensions:

The Interactive Dynamic Sculpture will require AC/DC power adapter, voltage regulator, 3.5mm and 1/4” input jacks, buffering and mixing circuitry (potentiometers and op amps), Low-Pass filters, 4x20 LCD, 16 4x4 Button Keypad, LED indicators, a on-board electret microphone, CMOS SPST Audio Switches, function generator DIP, electromagnets, and a MSP430F248 Microcontroller with 48 GPIO pins and 48k memory. The dimensions of the base (component housing) will be no more than 28” x 4” x 4”, which should be sufficient space for the LCD screen and the keypad. The sculpture housing will be about 28” x 4” x 18” which should guarantee adequate space for the sculpture bodies. The dimensions of the LCD are 98.50mm x 61.00mm x 15.60mm (WxHxD) and the dimensions of the keypad are 2.7” x 3” x 0.36”. The overall structure of the project is shown below in Fig 1.

Sculpture Structure Sketch:

Figure 1

Ferrofluid

Sculptures

LCD Keypad EQ Dials

Microcontroller:

The sculpture will use Texas Instruments’ MSP430F248 Ultra-Low Power Microcontroller for providing a user interface via the LCD and keypad, turning on and off switches, and storing preset patterns and user input data. The MCU will use 9 GPIO pins for acquiring keypad data, 12 GPIOs for displaying data on the LCD and communicating with the MCU, 4 GPIOs for turning audio channels and the equalizer on/off, and 7 GPIOs for sending the preset data or the current user data to the proper electromagnet. The MSP430F248 also has 48KB (+ 256B of FLASH) of ROM and 4KB of RAM for storing the main program, preset pattern information, and current user settings. The MCU and its external components are shown below in Fig 2.

General MCU Layout:

Figure 2

External Interrupts:

All external interrupts are received from the keypad in order to change settings or switch modes. The 4 GPIO pins for the audio inputs and the equalizer will also control their respective indicator LEDs to show the user quickly what is controlling the electromagnets.

Analog Circuitry:

To reduce cost and program complexity, nearly all of the signal amplification, generation, and filtering will be done with analog circuitry. The audio inputs from the 1/4”, 3.5mm jacks, and the on-board microphone will all be filtered with a LPF to remove noise and frequency components outside the natural audible range. The signals will then be passed through a simple equalizer to adjust the signal’s bass, mid, and treble levels with a 3 different POTs, and then into the seven band graphic equalizer to generate DC voltages corresponding to the intensity of a specific frequency band. The signal will then pass into the amplification stage which will handle any additional amplification needed before the signal is used to drive each corresponding electromagnet directly.

For the preset and custom user adjustment modes, the analog DACs will be controlled digitally by the MCU’s 7 signal GPIO pins. The analog signal output of the DACs will then be amplified by the same stage as the audio signals, before they drive each electromagnet separately. The signal flow diagram is shown in Fig 3, and the general block diagram is shown in Fig 4.

Signal Flow General Block Diagram :

Figure 3

Overall Functional Block Diagram:

Figure 4

Power and Source Description:

The system will run off of an AC/DC power adapter with output voltage rails of 12− ¿+¿ ¿ ¿ , 5, and 3.3 volts. Power regulation standards will be implemented in the final product to keep the rails voltages constant. The 12v rail will power the keypad, the 5v rail will power most of the other components such as the op-amps and the EQ DIP, and the 3.3v rail will power the MSP340F248 and the audio switches.

For safety, all power conversions/regulation will be done inside the bottom electrical component housing to protect the user from high voltage levels and shock hazards. The power supply diagram is shown in Fig 5.

Power Supply Block Diagram:

Figure 5

Sustainability:

In order to minimize power consumption, the Interactive Dynamic Sculpture will be implemented with minimal parts, and low power components will be chosen where applicable. The system will run off of an AC wall outlet which will eliminate the need for batteries, and the waste they create. The worst case power dissipation is covered in table 1.

Table 1

Component Supply Voltage (v)

Max Current Maximum Power Dissipation (Watts)

16 Button Keypad 12 V 30mA 360mWLCD 4x16 5 V 4.2mA 21mWOPA835 Op-Amps(13) ± 5 V 13 x 40mA = 520mA 2.6WAudio Channel Switches SPST (CMOS Quad Bilateral)

3 V 5uA Negligible

Audio Jacks (1/4” and 3.5mm)

Line (-10dBV) Negligible

LED Indicators (7) 2 V 7 x (14mA) = 98mA 196mWMSP430F248

I/0 Core

3 V3 V

23 x 40mA = 920mA6mA

2.76W 63mW @ 16MHz

PCM61P DAC (7) ± 5 V 7 x 260mW = 1.82WMSGEQ7 7-Band EQ (1) 5 V 1 mA 5mWElectromagnets (7) ±5 V 7 x 0.5A = 7A 17.5W

Power Dissipation by Supply Rail:

12V Rail Dissipation = 360mW

5V Rail Dissipation = 21.95W

3V Rail Dissipation = 3.02W

Total Power Dissipation = 25.33W

Software Requirements:

The Sculpture software will be written in C using Code Composer Studio. A brief summary of the MCU software functions are shown in table 2.

Table 2

Function Name DescriptionWelcome Displays a welcome message and info on how

to start using the sculpture.Get Keypad Data Takes keypad data and change sculpture

parameters such as channel selection and driving signal data.

Display LCD Data Displays modes and inputted data on LCD. Preset Accesses a predetermined signal sequence

and output with send signal function.User Stores user input data for signal transmission

to the electromagnets.Channel Enable Enables channels and equalizer switches.Send Signal Sends user/preset signal data to DACs.Help Displays a help menu and help info on LCD.

User Interface and Flow Diagram:

The user interface will be a 16 key keypad for the user to navigate the menu displayed on the 4x16 LCD. The user will be able to choose from 3 different modes including Audio, Custom, or Preset. The Audio mode will have 3 different options for the source input including the 1/4”, 3.5mm, and ambient internal microphone. From there the user will select whether or not the equalizer should be enabled and then the proper channel will be opened, with or without the equalizer section. The system will then return the user to the mode select menu to where it will stay until another command is received. The Preset mode will ask the user to select a specific preset pattern, and then return them to the mode select menu. The custom input mode will have the user select a specific magnet, then the signal type, then the amplitude, and then the frequency before confirming that the user is finished. Once finished the display will ask the user to select another magnet and the process will start over. When choosing each signal setting, there will be the option to go back to the previous setting, or to go back to the mode selection menu. The interface flow diagram is shown in Fig 6.

User Interface Flow Diagram:

Figure 6

Development Plan:

The seven-band graphic equalizer DIP and the toner powder for making ferrofluid have already been ordered, but more research/experimenting needs to be done in order to figure out the requirements for the other analog components such as the LPFs. Over winter break, the prototype for the bottom and top casing chambers will be built, and the ferrofluid will be experimented with to determine the requirements needed by the drive electromagnet circuitry, among other things. The detailed development plan is shown in Table 3.

Project Timeline:

Table 3

Start Date End Date Task Description

10/29/2012 11/4/2012 Finish Final Project Proposal.

11/5/2012 12/2/2012 Work on hardware schematic and finding exact parts to order.

12/3/2012 12/7/2012 Finish Final Project Description and order parts.

12/10/2012 12/14/2012 FINALS and winter break starts.

12/18/2012 1/6/2013 Collect/build sculpture pieces and encasement.

1/7/2013 1/21/2013 Create full schematic of all components.

1/21/2013 2/3/2013 Prototyping: Electromagnets, drive circuitry, and power supply

2/4/2013 2/18/2013 More Prototyping: Finish drive circuitry and power supply, Start graphic EQ.

2/19/2013 3/3/2013 More Prototyping: Finish graphic EQ.

3/4/2013 3/17/2013 Start user interface and software development.

3/18/2013 3/31/2013 FINALS and spring break: nothing planned

4/1/2013 4/14/2013 Finish software development and coding.

4/15/2013 4/28/2013 Debug System

4/29/2013 5/5/2013 Create Software presentation .

5/6/2013 5/26/2013 Debug System and revise code.

5/27/2013 6/2/2013 Prepare for demonstration.

6/3/2013 6/3/2013 DEMONSTRATION

6/10/2013 6/14/2013 FINALS

Prototype Fixture Layout:

The bottom electronics compartment and the top viewing chamber will be constructed out of Plexiglas for visibility of the internal components. There will also be an access panel on the electronics compartment for troubleshooting components and all analog components will be surface mounted on a PCB for the final product after the system has been tested on a breadboard. The Plexiglas chambers will be used in the final design so the user can see the components and the general inner workings of the design. I chose Plexiglas as a building material because it’s clear and also very durable to help protect against breaks and possible ferrofluid leakage.

Development Tools:

Most of the development will be done with analog equipment through WWU’s EET lab. Testing the system will be done using the function generator, oscilloscope, DMM, and power supplies. Once the analog circuitry has been tested and verified for proper operation, the MCU and software will be tested with each sub system separately.

Electrical Specifications:

Specifications for the supply voltages, Maximum signal gain, audio signal line levels, and safe operating temperature are shown in Table 4 below.

Table 4

Specification DescriptionSupply Voltages ±5V, 12V, 3VMaximum Gain +20dBMaximum Bass Amplification +20dBMaximum Middle Amplification +20dBMaximum Treble Amplification +20dBMaximum 7-Band Equalizer Gain +24dBLine Level -10dBVMaximum Electromagnet Current 1AOperating Temperature 0 – 70 ℃

Parts List:

Table 5

Part Distributer Manufacturer Part No. Quantity Price per Unit

Lead Time

Black Toner Powder (1kg)

Lucky Store (China)

N/A N/A 1 $25.50 2 Weeks

7-Band Graphic Equalizers (4)

Aliexpress Mixed Signal Integration Corporation

MSGEQ7 1 $3.99 Received

16 Button 4x4 Keypad

All Electronics

ACT Components Inc.

ACT-07-30008-000

1 $12.50 Not Ordered

20x4 LCD Digi-Key Kyocera Display America, Inc.

C-51847NFJ-SLW-ADN

1 $17.72 Not Ordered

MCU Texas Instruments

Texas Instruments

MSP430F248 1 Free Sample

Received

DAC Aliexpress Burr-Brown PCM61P 7 $2.66 Not Ordered

CMOS Quad Bilateral Switch

Texas Instruments

Texas Instruments

CD4066B 1 Free Sample

Not Ordered

1/4” Stereo Input Jack

Digi-Key Switchcraft 112BPCX 1 $2.88 Not Ordered

Stereo 3.5mm Mini-Phone Jack

All Electronics

N/A SMJ-2 1 $0.85 Not Ordered

Op-Amps Texas Instruments

Texas Instruments

OPA835 13 Free Samples

Not Ordered

Ferrite U-Core (Electromagnets)

TSC Ferrite International

TSC Ferrite International

39-19-10 7 $0.39 Not Ordered

Mid-Range Speaker

N/A N/A N/A 1 Free (Salvage)

Obtained

Electret Microphone

All Electronics

Hosiden KUB2823 2 $0.50 Not Ordered

800 pt. Solderable Breadboard

All Electronics

All Electronics SB-800 1 $6.50 Not Ordered

Total Cost = $92.29

END OF DOCUMENT