Electronics and Networks: Week 3: Dumb things with Wires (II)Sensors and Motors

Jonah Brucker-CohenMatthew KarauMonday 10am - 12pmTrinity College Dublin MSc. Multimedia SystemsSpring 2003

Reading: Tyranny of the Moment

• Time = commodity• Slow Time vs Fast Time = private periods where we are able to think without interruption are the most valuable

• Fighting for unavailability• Past = finding information

• Present = filtering information

• More Technology = less time

Any Thoughts?

Sensors and Motors Overview

• What are sensors and how can we use them?• Examples of sensors (digital vs. analog)• Sensors we have to play with• Sensors in use• What are motors and how can we use them?• Examples of Motors• Motor Controllers• Motors in use• In Class Lab

What are sensors and how can we use them?

• Sensors: Anything that receives a stimulus and can respond to it

Example: Human - touch, taste, smell, see Machine - switch, pressure, light, heat, time, direction, force• Sensors are used for• controlling devices, reading• input from the body, space,• environment• Connected to BS2 sensors can provide input to drive objects locally or through serial connections

• Digital sensors return on/off values• Switches: rocker switch, button, magnet switch, photo transistor,

transistors, hall effects, pressure threshold, thermal, IR switch

Examples of Sensors: Digital

Others: Accelerometer, optical encoders

• Analog Sensors return a gradual range of values• Examples: Force Sensitive Resistors, Variable resitors:

Potentiometers (pots), photo resistor, thermistor (heat), Sonar

Examples of Sensors: Analog

Sensors we have to play with!

• Rocker Switches• Potentiometers• Hall Effects• Accelerometers (coming soon)• IR detectors/emmiters• Sensors you come up with!

Sensors in Use• Examples of Sensors used in projects

Crank the web: magnets

Copper Urchin: homemade switches

Brain Ball: Brainwave Sensor

Text Rain: camera

What are Motors and how can we use them?• Motors are electrically charged magnets that pull or push on each other in one direction or another. The field magnet is stationary while the armature (with wire couled around it) or electromagnet is repelled or attracted by the field magnet.• We can use motors for lots of things:

cars, appliances,fans, clocks,

massagers, mobile phones, CD Players, tape decks, car windows, toys, disk drives, aqauriums…

Examples of Motors• DC motors: usually 3-5 vlts Used for simple, non-precise movement Ex. Fans, RC Cars, model trains High pin for BS2

• Servo motors: hobby version 5 vlts Used for controllers - such as direction on RC toys, robotics for positioning Pulsout command for BS2

• Stepper motors: Used for precise positioning - inkjet printers, digital plotters, steering, disk drives Motor controller needed

Motor Controllers • Motor Controllers are separate pieces of hardware that interface to

microcontrollers to control them - they all talk serial! A Few Examples:

• MotorMind B: allows you to control the polarity (backwards/forwards) Movement of a DC motor - Ex. If you wanted to make your own RC Car

• Little Step U - Used for controlling Stepper Motors For instance if you want to turn your desk Chair into a rotating clock

• Ferret FT639: controls up to 5 Servo motors at once through serial If you wanted to make a robot walk - you can with one chip

Motors in use!Examples of cool projects that use lots o’ motors

Robotlab: jukebots

Snibbe: Breath Recorder

Scratch Machine

Danny Rozin: Wooden Mirror500 Servo Motors turns wood into video

In Class LabPlay with stuff in class