New%20Human%20Computer%20Interfaces

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New Human Computer Interfaces
Class ? May 30 2007

• Amnon Dekel
• HUJI CSE, Spring 2007

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On the Menu

• Project Idea Presentations and Discussion
• Serial Communications
• Some more sensors
• Changing the world Actuators
• Milestones for the rest of the semester

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Serial Communications

• The Ardiono can communicated with other devices
  in the world using the Serial Communications
  Protocol
• You can use this to have a board Send data to
  another board and receive data from another
  board.
• You can also use this to have the board
  communicate with a workstation (Why?)

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Serial Communications

• This communication happens via the Arduino
  board's serial or USB connection and on digital
  pins 0 (RX) and 1 (TX). Thus, if you use these
  functions, you cannot also use pins 0 and 1 for
  digital i/o.
• Serial.begin(speed)
• int Serial.available()
• int Serial.read()
• Serial.flush()
• Serial.print(data)
• Serial.println(data)
• WORKSHOP http//itp.nyu.edu/physcomp/Labs/Serial

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Some More About Sensors
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Types of Input
Switches
Rocker switch
Push button
Slide switch
Toggle switch
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Sensitive Switches
Roller switch
Hair trigger/whisker switch
Magnetic/Reed switch
Mercury/Tilt switch
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Analog Sensors
Force Sensitive Resistor (FSR)
Pressure sensors
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Analog Sensors
Photocell
Temperature Sensor/Thermistor
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And more
And more Capacitance sensors Piezoelectric
sensors
Accelerometers
Flex Sensor
More info ITP Sensor Workshop Report
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Changing the World Actuators
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Examples
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Actuators

• Pneumatic
• Air Pressure causing movement
• Hydraulic
• Liquid Pressure causing movement
• Electronic
• Electro-magnetic movement
• Motors (Kinetic)
• Speakers (Audio)
• Lights (Visual)

More Info
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Motors

• Linear vs. Rotary movement
• Torque
• Gear

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Selecting a Motors

• Speed (RPM)
• Movement mechanics
• Controlling the Position
• Feedback about the position
• How much weight can it carry
• Torque
• How much power does it need
• Price

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Selecting a Motors

• Speed (RPM)
• Movement mechanics
• Controlling the Position
• Feedback about the position
• How much weight can it carry
• Torque
• How much power does it need
• Price

1. The moment of a force the measure of a
force's tendency to produce torsion and rotation
about an axis, equal to the vector product of
the radius vector from the axis of rotation to
the point of application of the force and the
force vector. 2. A turning or twisting force.
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Types of Motors
Stepper
DC
DC servo
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Motors

• DC Motor
• Cheap.
• Very easy to connect
• Minimum control
• Turns 360 degrees.
• Can add components for more control
• Speed change the voltage using a POT
• Direction change the polarity
• Position cant! ? Add an H-Bridge circuit

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Motors

• DC Servo
• Expensive
• Very easy to connect
• Includes all components
• Turns 90 degrees to each side
• Full control
• Speed change the voltage
• Position Needs CHECKING

Waiting for answer from Oren
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Controlling a Servo

• DC Servo - Controlling the position
• They rotate 0 to 180 degrees depending on the
  pulsewidth. About 1.5 sec to move 180 degrees.
• The DC Servo takes a pulse of between 1-2 ms
  every 20 ms.
• A pulse of 1 ms will turn the motor to 0 degrees
  1.5 MS will turn to 90 degrees, 2 ms will turn it
  to 180 degrees
• To keep a servo in its current position pulse it
  with the same pulse width every 18-20 ms to keep
  it there.

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Motors

• Stepper
• Cheap
• Usually 12V
• Hard to connect
• Need extra components
• Turns 360 degrees.
• Can stay still in one position
• Full control
• Position
• Speed

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Controlling Motors

• We want to control a few elements
• Speed
• Strength
• Direction
• Position

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Controlling Motors

• We want to control a few elements
• Speed ? power
• Strength ? Current
• Direction ? current direction/Pulse
• Position ? Pulse

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Controlling Motors

• Controlling the position

DC Motor
BS1
Controller ??? (H-Bridge)
PWM
????Feedback
Encoder
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Controlling Motors

• Using PWM to control the position
• For each motor we know the RPM in X Volt, how
  many rounds per minute.
• From this info we can calculate how many degrees
  a pulse moves in a certain time.
• When accuracy is important inertia should be
  taken into account (and gear to balance it)

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Where to get motors?
?????? ??????
?????? ????????
?????? ??????????
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PAUSE

• What have we been dealing with so far?

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Controlling the world?
?Sensing the world
Vision
Video
SOUND
Pressure
Analog Output
Controlling 220V world
Digital Input
Computing
Change
Analog INPUT
Output to the PC
Digital Output
Communications
Position
MOVEMENT (Motors)
Movement
Audio
Temperature
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Projects

• Whats a good project?
• Process
• Milestones
• Presentations

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Whats a Good Project

• Explores interesting, and preferably, novel
  scenarios
• Shows interesting use of the technology
• Exhibits a working prototype for at least one
  main part of the scenario.
• Explains how it fits into the wider scenario.
• Includes good documentation
• Project explanation, process, problems, code,
  possible improvements
• Project Poster

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Project

• If we have time
• Class Discussion of Projects
• Home Work
• Prepare a Project Proposal
• Intro What problem am I trying to solve
• Research (what exists)
• Concept
• Technology
• Milestones (7 weeks)