New Human Computer Interfaces

Amnon DekelHUJI – CSE, Spring 2006

Class 5May 9 2006

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On the Menu

• Group Exercise Review

• Serial Port: – Board2Board– Board2PC– PC2Board

• Some more sensors

• Changing the world: Actuators

• Projects

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Exercise Review

• View the exercise projects

• Problems and Difficulties?

• What Have You Learned?

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Serial Communications

• The OpenBoard 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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Board to Board

• Call soft-serial-on once at the beginning of the program.• Sending Values:

– Sending is done from Pin C0. – the command:

send1 value i.e. send1 100

• Receiving Values:– You can receive on 4 ports: B0, B1, B2, B3– To receive you need to do 2 things:

• check if a new value has been received on the pin. newin1? will check B0 (newin2? will check B1, newin3? will check B2, newin4? will check B3).

The code: loop [ if newin1? [do something with in1] ]

– Oren comments: to use in1 best to set it into a different variable, like: settemp in1 if temp = 100 [do something else]

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Board to PC• Use the regular programming cable configuration

Sending to the PC:• Use the send command (not send1). Anything sent this way will be sent to the PC serial port.

send value

Reading the data on the PC1. Make sure the PC is in fact receiving the data. Use a terminal program for this (like Hyperterm) 2. If all is well- write a program (in Java, C, whatever you like) to read the serial port.

Sending data to the Board from the PC:• You use the following primitives in your code on the board:

enable-recc (to enable receiving of serial data) recc? (check if a value is waiting in the serial buffer) recc (the value itself, so you can set into another variable)

• To send serial data to the board, use the send <8 bit integer> command from the programming environment.

• To send serial data from a different application on your PC, it should work just by sending numbers to the serial line, so enable the serial line and send an integer.

Some More About Sensors

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Push button Slide switch Toggle switch Rocker switch

Types of InputSwitches

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Sensitive Switches

Hair trigger/whisker switch

Roller switch

Mercury/Tilt switch Magnetic/Reed 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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Accelerometers Flex Sensor

And more …

And more:Capacitance sensors

Piezoelectric sensors

More info: ITP Sensor Workshop Report

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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• Linear vs. Rotary movement

• Torque

• Gear

Motors

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• 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

Selecting a Motors

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• 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

Selecting a Motors

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 servo

DC

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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: can’t! Add an H-Bridge circuit

Motors

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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

Motors

Waiting for answer from Oren

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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.

Controlling a Servo

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

– Position– Speed

Motors

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We want to control a few elements:

• Speed

• Strength

• Direction

• Position

Controlling Motors

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We want to control a few elements:

• Speed power

• Strength Current

• Direction current direction/Pulse

• Position Pulse

Controlling Motors

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Where to get motors?

חנויות טיסנים חנויות רובוטיקה

חנויות אלקטרוניקה

PAUSE

What have we been dealing with so far?

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Vision

SOUND

Analog INPUT

Digital Input

Sensing the worldControlling the world

Digital Output

Analog Output

Computing

Communications

MOVEMENT(Motors)

Output to the PC

Controlling 220V world

Movement

Position

Change

Pressure

TemperatureAudio

Video

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Projects

• What’s a good project?

• Process

• Milestones

• Presentations

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What’s 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)