02-20-2012, 02:08 AM
Why Get A Mechanical Keyboard?
People invest lots of money on mechanical keyboards for various reasons. Maybe they grew up with them and have fond memories of a IBM Model M pinging away. Maybe they got tired of throwing out mushy rubber domes every three years. The best reason is Mechanical Keyboards just feel better and they will make you more efficient at gaming/typing. After you try one most people find standard rubber dome keyboards mushy and boring! Unfortunately Mechanical Keyboards cost more than the $5 throwaway keyboard that comes with most computers and the first reaction you have may be "why bother - my keyboard works fine". Keyboards are the primary way in which you interact with your computer. Think about how much money you spend on the other devices you use to interact with your computer - computer mice (you probably have several), computer monitor, and graphics card. Your fingers deserve the best.
Mechanical keyboards are not easy to try out in the stores so the next part of the wiki will go into describing mechanical switches in some detail in an attempt to make it easier to imagine what they will feel like. Lots of pictures "under the hood" are included to help you with this.
Why Is It Called a Mechanical Switch Keyboard?
A typical "rubber dome" Keyboard looks like this. A peg will press down on a membrane with two conductive circles. A microcontroller scans what is called the switch matrix and information is sent to the PC.
![[Image: attachment.php?attachmentid=21009&d=1310786771]](http://geekhack.org/attachment.php?attachmentid=21009&d=1310786771)
Photo courtesy of cfishy
Take special note of that peg in the center of the dome. That peg when pushed to the bottom will press two membrane conductive "pads" together to form a circuit.
![[Image: attachment.php?attachmentid=29223&d=1319157065]](http://geekhack.org/attachment.php?attachmentid=29223&d=1319157065)
Animation courtesy of Lethal Squirrel
Another variation of the rubber dome switch is a scissor switch first used in laptops/netbooks but now on keyboards such as the Apple Aluminum. It's called "scissor switch" because under each key are plastic stabilizers. This allows the manufacturer to make a highly tactile small diameter and short length rubber dome without the switch not working because of off-center hits on the keys. You can see why it's called a "Scissor" switch because of the stabilizers. These scissors sit over the rubber dome and work in a similar manner. They do not provide any "spring" but act purely as stabilizers, making offcenter hits register correctly.
![[Image: attachment.php?attachmentid=29224&d=1319157093]](http://geekhack.org/attachment.php?attachmentid=29224&d=1319157093)
Animation courtesy of Lethal Squirrel
Mechanical keyboards all are designed to allow you to type without bottoming out to activate the switch. They generally (not always) rely on metal contacts and a spring in an individual switch. Capacitive circuits are included in this guide as well as buckling spring switches which use a spring/hammer mechanical action to press a membrane switch. Although they don't use metal contacts to close or open the switch they share having a mid-point activation in the switch travel. The end result is a switch with longer key travel and a precise feel.
A capacitive circuit. Although not "mechanical" in the sense of having metal contacts SOME foam/foil (not all - many early PCs use simple foam over foil contact switches) and Topre capacitive spring circuits use capacitance to activate the switch BEFORE it bottoms out.
Common Mechanical Switches
Cherry MX
A Mechanical switch often (not always) consists of a spring and two metal contacts like this.
A Cherry MX switch. Notice the gold on the contact point, what Cherry Corp. calls "Gold Crosspoint Contacts".
Keyboards switches are called SPST NO Momentarys by engineers. SPST - "Single Pole, Single Throw" means they are a simple switch that is either on or off, like a light switch. NO - means "Normally Open" - in other words continuing with that light switch analogy the lights are normally "OFF". "Momentary" means that as you push the switch down the lights go on and as you release the switch the lights go off.
Here is an animated GIF showing that as the key depressed the plastic "fingers" on the switch allow the spring metal switch to close and then re-open on the way back up. The "feel" of the Cherry MX switch is determined mainly by the profile of the plastic "fingers" and the stiffness of the spring.
![[Image: attachment.php?attachmentid=15446&d=1297554097]](http://geekhack.org/attachment.php?attachmentid=15446&d=1297554097)
![[Image: attachment.php?attachmentid=15450&d=1297554312]](http://geekhack.org/attachment.php?attachmentid=15450&d=1297554312)
![[Image: attachment.php?attachmentid=15449&d=1297554254]](http://geekhack.org/attachment.php?attachmentid=15449&d=1297554254)
The Cherry Blue, Green and rare Cherry "White" switches have two piece stems and make a plasticy Legolike "Click" sound as the two pieces snap against each other.
![[Image: attachment.php?attachmentid=15447&d=1297554154]](http://geekhack.org/attachment.php?attachmentid=15447&d=1297554154)
IBM Buckling Springs over Membrane Switches
IBM chose another mechanical arrangement where a buckling spring slaps a hammer down on a membrane.
A key sits on top of this spring which is attached to a hammer which slaps a membrane switch similar to the one in a common rubber dome keyboard.
![[Image: Modelm-cross.jpg]](http://deskthority.net/w/images/7/7e/Modelm-cross.jpg)
pic stolen from Deskthority.net
Hope you enjoyed support forum members!
People invest lots of money on mechanical keyboards for various reasons. Maybe they grew up with them and have fond memories of a IBM Model M pinging away. Maybe they got tired of throwing out mushy rubber domes every three years. The best reason is Mechanical Keyboards just feel better and they will make you more efficient at gaming/typing. After you try one most people find standard rubber dome keyboards mushy and boring! Unfortunately Mechanical Keyboards cost more than the $5 throwaway keyboard that comes with most computers and the first reaction you have may be "why bother - my keyboard works fine". Keyboards are the primary way in which you interact with your computer. Think about how much money you spend on the other devices you use to interact with your computer - computer mice (you probably have several), computer monitor, and graphics card. Your fingers deserve the best.
Mechanical keyboards are not easy to try out in the stores so the next part of the wiki will go into describing mechanical switches in some detail in an attempt to make it easier to imagine what they will feel like. Lots of pictures "under the hood" are included to help you with this.
Why Is It Called a Mechanical Switch Keyboard?
A typical "rubber dome" Keyboard looks like this. A peg will press down on a membrane with two conductive circles. A microcontroller scans what is called the switch matrix and information is sent to the PC.
Photo courtesy of cfishy
Take special note of that peg in the center of the dome. That peg when pushed to the bottom will press two membrane conductive "pads" together to form a circuit.
Animation courtesy of Lethal Squirrel
Another variation of the rubber dome switch is a scissor switch first used in laptops/netbooks but now on keyboards such as the Apple Aluminum. It's called "scissor switch" because under each key are plastic stabilizers. This allows the manufacturer to make a highly tactile small diameter and short length rubber dome without the switch not working because of off-center hits on the keys. You can see why it's called a "Scissor" switch because of the stabilizers. These scissors sit over the rubber dome and work in a similar manner. They do not provide any "spring" but act purely as stabilizers, making offcenter hits register correctly.
Animation courtesy of Lethal Squirrel
Mechanical keyboards all are designed to allow you to type without bottoming out to activate the switch. They generally (not always) rely on metal contacts and a spring in an individual switch. Capacitive circuits are included in this guide as well as buckling spring switches which use a spring/hammer mechanical action to press a membrane switch. Although they don't use metal contacts to close or open the switch they share having a mid-point activation in the switch travel. The end result is a switch with longer key travel and a precise feel.
A capacitive circuit. Although not "mechanical" in the sense of having metal contacts SOME foam/foil (not all - many early PCs use simple foam over foil contact switches) and Topre capacitive spring circuits use capacitance to activate the switch BEFORE it bottoms out.
Common Mechanical Switches
Cherry MX
A Mechanical switch often (not always) consists of a spring and two metal contacts like this.
A Cherry MX switch. Notice the gold on the contact point, what Cherry Corp. calls "Gold Crosspoint Contacts".
Keyboards switches are called SPST NO Momentarys by engineers. SPST - "Single Pole, Single Throw" means they are a simple switch that is either on or off, like a light switch. NO - means "Normally Open" - in other words continuing with that light switch analogy the lights are normally "OFF". "Momentary" means that as you push the switch down the lights go on and as you release the switch the lights go off.
Here is an animated GIF showing that as the key depressed the plastic "fingers" on the switch allow the spring metal switch to close and then re-open on the way back up. The "feel" of the Cherry MX switch is determined mainly by the profile of the plastic "fingers" and the stiffness of the spring.
The Cherry Blue, Green and rare Cherry "White" switches have two piece stems and make a plasticy Legolike "Click" sound as the two pieces snap against each other.
IBM Buckling Springs over Membrane Switches
IBM chose another mechanical arrangement where a buckling spring slaps a hammer down on a membrane.
A key sits on top of this spring which is attached to a hammer which slaps a membrane switch similar to the one in a common rubber dome keyboard.
pic stolen from Deskthority.net
Hope you enjoyed support forum members!
