(edit sidebar)
Intro to Physical Computing Syllabus

Research & Learning

Other Class pages

Shop Admin

ITP Help Pages
Tom's pcomp site
DanO's pcomp site


Switches

Labs.Switches History

Hide minor edits - Show changes to output

Changed line 110 from:
%lfloat width=300 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
to:
%lfloat height=300 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
Changed line 113 from:
%width=300 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
to:
%height=300 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
Changed line 118 from:
%lfloat width=300 alt='Switching a motor and an LED'%[[Attach:switch_motor_led_bb.png|Attach:switch_motor_led_bb.png]]\\
to:
%lfloat height=300 alt='Switching a motor and an LED'%[[Attach:switch_motor_led_bb.png|Attach:switch_motor_led_bb.png]]\\
Changed line 121 from:
%width=300 alt='Switching a motor and an LED schematic'%[[Attach:switch_motor_led_schem.png|Attach:switch_motor_led_schem.png]]\\
to:
%height=300 alt='Switching a motor and an LED schematic'%[[Attach:switch_motor_led_schem.png|Attach:switch_motor_led_schem.png]]\\
Changed lines 111-112 from:
[-Switches in series -- schematic-]
[[<<]]
to:
[-Switching a motor -- breadboard-]
Changed lines 114-115 from:
[-Switches in series -- breadboard-]
to:
[-Switching a motor -- schematic-]
Changed lines 119-120 from:
[-Switches in series -- schematic-]
[[<<]]
to:
[-Switching a motor and an LED with a dual pole switch -- breadboard-]
Changed line 122 from:
[-Switches in series -- breadboard-]
to:
[-Switching a motor and an LED with a dual pole switch -- schematic-]
Changed lines 9-13 from:
'''Single Throw''' means there's only two contacts. The switch is open or closed.  '''Dual Throw''' means there's at least three contacts, and switching the switch moves the center contact from being closed with one outer contact to being closed with the other outer contact.

'''Single Throw''' means there's only one ser of contacts being closed or open by the switch's mechanism.  '''Dual Throw''' means there's two sets of contacts being controlled by the same mechanism.  With a dual throw
switch, you can switch two separate circuits with the same mechanism.

to:
'''Single Throw''' means there's only two contacts. The switch is open or closed.  '''Dual Throw''' means there's at least three contacts, and switching the switch moves the center contact from being closed with one outer contact to being closed with the other outer contact. Dual throw switches have at least three positions, typically

'''Single Pole''' means there's only one set of contacts being closed or open by the switch's mechanism.  '''Dual pole''' means there's two sets of contacts being controlled by the same mechanism.  With a dual pole
switch, you can switch two separate circuits with the same mechanism.

Changed line 110 from:
%lfloat width=400 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
to:
%lfloat width=300 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
Changed lines 113-114 from:
%width=400 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
[-Switches in series -- breadboard-]
to:
%width=300 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
[-Switches in series -- breadboard-]

With a dual pole switch, you could control both a motor ''and'' an LED like so:

%lfloat width=300 alt='Switching a motor and an LED'%[[Attach:switch_motor_led_bb.png|Attach:switch_motor_led_bb.png]]\\
[-Switches in series -- schematic-]
[[<<]]
%width=300 alt='Switching a motor and an LED schematic'%[[Attach:switch_motor_led_schem.png|Attach:switch_motor_led
_schem.png]]\\
[-Switches in series -- breadboard-]
Changed line 112 from:
to:
[[<<]]
Changed lines 2-4 from:
=======
(:toc Table of Contents:)

to:
Changed line 110 from:
%lfloat width=200 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
to:
%lfloat width=400 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
Changed line 113 from:
%width=200 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
to:
%width=400 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
Changed line 112 from:
%lfloat height=200 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
to:
%lfloat width=200 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
Changed line 115 from:
%height=200 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
to:
%width=200 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
Changed lines 108-116 from:
to:
!! Switching a motor

In a simple circuit, a motor is no different than an LED as a load. You can swtich it as well. Make sure your power supply can supply the current and amperage that your motor requires.

%lfloat height=200 alt='Switching a motor'%[[Attach:switch_motor_bb.png|Attach:switch_motor_bb.png]]\\
[-Switches in series -- schematic-]

%height=200 alt='Switching a motor schematic'%[[Attach:switch_motor_schem.png|Attach:switch_motor_schem.png]]\\
[-Switches in series -- breadboard-]
Added lines 84-85:
For more ideas on materials, check out [[http://www.kobakant.at/DIY/|How to Get What You Want]]. They have an excellent list of conductive materials and instructions.
Changed lines 104-106 from:
Through a combination of series and parallel switches, you can come up with a variety of combinations that make the light turn on.  Depending on where you add the LEDs, you can even have the same switches turn on different LEDs in different combinations.

to:
Through a combination of series and parallel switches, you can come up with a variety of combinations that make the light turn on.  Depending on where you add the LEDs, you can even have the same switches turn on different LEDs in different combinations. Try a few combinations and see what happens.

Added lines 104-106:
Through a combination of series and parallel switches, you can come up with a variety of combinations that make the light turn on.  Depending on where you add the LEDs, you can even have the same switches turn on different LEDs in different combinations.

Changed line 93 from:
%lfloat height=200 alt='Switches in parallel%[[Attach:switches_parallel.png|Attach:switches_parallel.png]]\\
to:
%height=200 alt='Switches in parallel%[[Attach:switches_parallel.png|Attach:switches_parallel.png]]\\
Changed line 101 from:
%lfloat height=200 alt='Switches in series%[[Attach:switches_series.png|Attach:switches_series.png]]\\
to:
%height=200 alt='Switches in series%[[Attach:switches_series.png|Attach:switches_series.png]]\\
Changed lines 82-103 from:
Come up with an everyday activity to which you can add three or four custom switches that, when combined, turn on a light.  For example, maybe the light comes on when you close the door, sit down, and open a book.  Or when you walk upstairs, put your keys on a side table, and remove your hat.  Combine your creativity with switches with what you learned in the [[Electronics|electronics lab]] to make this happen.
to:
Come up with an everyday activity to which you can add three or four custom switches that, when combined, turn on a light.  For example, maybe the light comes on when you close the door, sit down, and open a book.  Or when you walk upstairs, put your keys on a side table, and remove your hat.  Combine your creativity with switches with what you learned in the [[Electronics|electronics lab]] to make this happen.

!! Arrangements of switches

In planning your switch project, consider what happens when you arrange switches in different ways.  For example, try this circuit:

!!! Three switches in parallel. Any one of the three will turn on the LED

%lfloat height=200 alt='Switches in parallel%[[Attach:switches_parallel_schem.png|Attach:switches_parallel_schem.png]]\\
[-Switches in parallel -- schematic-]

%lfloat height=200 alt='Switches in parallel%[[Attach:switches_parallel.png|Attach:switches_parallel.png]]\\
[-Switches in parallel -- breadboard-]

!!! Three switches in series.  All three must be on to turn on the LED

%lfloat height=200 alt='Switches in parallel%[[Attach:switches_series_schem.png|Attach:switches_series_schem.png]]\\
[-Switches in series -- schematic-]

%lfloat height=200 alt='Switches in series%[[Attach:switches_series.png|Attach:switches_series.png]]\\
[-Switches in series -- breadboard-]

Deleted lines 4-6:
!!  Switches in Parallel

Changed lines 83-85 from:
to:
Make your own switch.  Find a way to turn a closing door into a switch, for example, or to close a switch when a person sits down.  Or figure out how to turn a hat into a switch, or a cane, or a zipper. Or perhaps the pieces of a puzzle can be switches.

Come up with an everyday activity to which you can add three or four custom switches that, when combined, turn on a light.  For example, maybe the light comes on when you close the door, sit down, and open a book.  Or when you walk upstairs, put your keys on a side table, and remove your hat.  Combine your creativity with switches with what you learned in the [[Electronics|electronics lab]] to make this happen.
Changed lines 65-66 from:

%lframe height=200 alt='conductive fabric'%[[Attach:conductive_fabric.jpg|Attach:conductive_fabric.jpg]]\\
to:
(:table border=0:)
(:cellnr:)
%
height=200 alt='conductive fabric'%[[Attach:conductive_fabric.jpg|Attach:conductive_fabric.jpg]]\\
Changed line 69 from:
to:
(:cell:)
Changed lines 72-73 from:

%rframe height=200 alt='copper tape'%[[Attach:copper_tape.jpg|Attach:copper_tape.jpg]]\\
to:
(:cell:)
%height=200 alt='copper tape'%[[Attach:copper_tape.jpg|Attach:copper_tape.jpg]]\\
Changed lines 75-76 from:
to:
(:tableend:)
Changed line 79 from:
%rframe height=200 alt='soft switches%[[Attach:soft_switches.jpg|Attach:soft_switches.jpg]]\\
to:
%height=200 alt='soft switches%[[Attach:soft_switches.jpg|Attach:soft_switches.jpg]]\\
Added lines 63-81:

A switch is nothing more than a mechanism to bring two pieces of conductive material together and separate them.  You can make a switch from any two conductors and a little creativity.  Consider, for example:

%lframe height=200 alt='conductive fabric'%[[Attach:conductive_fabric.jpg|Attach:conductive_fabric.jpg]]\\
[-conductive fabric-]

%height=200 alt='wire mesh'%[[Attach:wire_mesh.jpg|Attach:wire_mesh.jpg]]\\
[-wire mesh-]

%rframe height=200 alt='copper tape'%[[Attach:copper_tape.jpg|Attach:copper_tape.jpg]]\\
[-copper tape-]

All you need to do is arrange the two conductors in such a way that they can touch or not touch.  Sometimes a spacer layered between the two conductors helps.  For example, in this image you see three pieces of conductive fabric.  Two of the pieces have non-conductive layers on top of them.  When the non-conductive part is sandwiched between the conductive layers, you've got a switch that's pressed by touching.  The conductive parts touch when they're pressed through the holes in the non-conductive part. These two switches would have different sensitivities because the hole-to-material ratio of the non-conductive layer is different.

%rframe height=200 alt='soft switches%[[Attach:soft_switches.jpg|Attach:soft_switches.jpg]]\\
[-soft switches-]


Changed lines 26-27 from:
'''Pushbuttons''' or '''momentary switches''' stay closed only as long as you hold them closed.  Roller switches are pushbuttons with a lever and a roller attached.  They're useful when you need something to push against the switch gently to close it.
to:
'''Pushbuttons''' or '''momentary switches''' stay closed only as long as you hold them closed.  '''Roller switches''' are pushbuttons with a lever and a roller attached.  They're useful when you need something to push against the switch gently to close it.
Added lines 41-61:
'''Magnetic switches''' have two metal leaves in the end that are pulled together when a magnet is brought close to them.  They're useful when you can't have wires on both sides of the switch mechanism.

%height=200 alt='magnetic switch'%[[Attach:magnetic_switch.jpg|Attach:magnetic_switch.jpg]]\\
[-Magnetic Switch-]

'''Magnetic snaps''' are useful when you're making a soft circuit and need a fastener on the garment to close a switch.

%height=200 alt='magnetic snap'%[[Attach:magnetic_snap.jpg|Attach:magnetic_snap.jpg]]\\
[-Magnetic Snap-]

'''Whisker switches''' are made from a piece of spring steel or piano wire, and a center post.  An insulator such as a piece of electrical tape or shrinkwrap holds the two separate.  When the wire is touched, the spring bends and touches the metal post, and closes the switch. [[http://www.solarbotics.com|Solarbotics]] sells some nice whisker switches.

%height=200 alt='whisker switch'%[[Attach:whisker_switch.jpg|Attach:whisker_switch.jpg]]\\
[-Whisker Switch-]

'''Tilt switches''' contain a metal ball and contacts at one end.  When you tilt the switch, the ball touches both contacts, and closes the switch.  There are also '''mercury switches''' that do the same, but with a ball of mercury inside.  Avoid these, since mercury is very poisonous.

%height=200 alt='tilt switch'%[[Attach:tilt_switch.jpg|Attach:tilt_switch.jpg]]\\
[-Whisker Switch-]

Changed lines 26-28 from:
'''Pushbuttons''' or '''momentary switches''' stay closed only as long as you hold them closed. 

%height=200
alt='pushbutton'%[[Attach:pushbutton.jpg|Attach:pushbutton.jpg]]\\
to:
'''Pushbuttons''' or '''momentary switches''' stay closed only as long as you hold them closed.  Roller switches are pushbuttons with a lever and a roller attached.  They're useful when you need something to push against the switch gently to close it.

%lfloat
height=200 alt='pushbutton'%[[Attach:pushbutton.jpg|Attach:pushbutton.jpg]]\\
Added lines 31-32:
%height=200 alt='roller switch'%[[Attach:roller_switch.jpg|Attach:roller_switch.jpg]]\\
[-roller switch-]
Changed line 23 from:
%lfloat height=200 alt='switches'%[[Attach:switches.jpg|Attach:switches.jpg]]\\
to:
%height=200 alt='switches'%[[Attach:switches.jpg|Attach:switches.jpg]]\\
Changed line 28 from:
%lfloat height=200 alt='pushbutton'%[[Attach:pushbutton.jpg|Attach:pushbutton.jpg]]\\
to:
%height=200 alt='pushbutton'%[[Attach:pushbutton.jpg|Attach:pushbutton.jpg]]\\
Deleted line 0:
Added lines 23-25:
%lfloat height=200 alt='switches'%[[Attach:switches.jpg|Attach:switches.jpg]]\\
[-various types of switches-]

Changed lines 28-30 from:
to:
%lfloat height=200 alt='pushbutton'%[[Attach:pushbutton.jpg|Attach:pushbutton.jpg]]\\
[-pushbutton-]

Changed lines 33-34 from:

to:
%lfloat height=200 alt='Toggle switch'%[[Attach:toggle_switch.jpg|Attach:toggle_switch.jpg]]\\
[-Toggle Switch-]

%height=200 alt='slide switch'%[[Attach:slide_switch.jpg|Attach:slide_switch.jpg]]\\
[-Slide Switch-]

Added line 1:
Changed lines 3-5 from:
to:
=======
(:toc Table of Contents:)

Changed lines 8-12 from:
!! Resistor Ladders

!!

!!
to:

!! Switch Terminology

There are a few basic terms that get used with switches all the time.

'''Normally Open''' means that when the switch is in its normal position, the contacts are not touching, or open. '''Normally closed''' means that when the switch is in its normal position, the contacts are touching, or closed.

'''Single Throw''' means there's only two contacts. The switch is open or closed.  '''Dual Throw''' means there's at least three contacts, and switching the switch moves the center contact from being closed with one outer contact to being closed with the other outer contact.

'''Single Throw''' means there's only one ser of contacts being closed or open by the switch's mechanism.  '''Dual Throw''' means there's two sets of contacts being controlled by the same mechanism.  With a dual throw switch, you can switch two separate circuits with the same mechanism.


!!! There are lots of types of switches. 

A few types are shown here:

'''Pushbuttons''' or '''momentary switches''' stay closed only as long as you hold them closed. 


'''Toggle switches''' stay closed in one physical position and open in the other.''' Slide switches''' are similar to toggle switches.



!! Get Creative With Switches
Added lines 1-2:
(:toc Table of Contents:)
Added lines 1-7:
!!  Switches in Parallel

!! Resistor Ladders

!!

!!
  Edit | View | History | Print | Recent Changes | Search Page last modified on September 01, 2013, at 07:30 PM