Mechanical Keyboards

I was 15 when I first heard about mechanical keyboards.

Two classmates were discussing the keyboard one of them had just purchased.  I thought to myself: Aren't mechanical keyboards those old, all-white keyboards with springs?  Why would anyone want such an archaic thing!?  I had no idea how wrong I was!

Most people use a $10, maybe $20, rubber dome keyboard.  Some have done so consciously while others may not know that a better alternative exists.

What you need to realize is that mechanical keyboards were actually first and they keep getting made today.  (While technically every keyboard switch that makes physical contact - unlike those light/optical switches - is considered mechanical, regular rubber domes are excluded when referring to a mechanical keyboard or mechanical keyboard switches.)

Remember the keyboard of that Apple ][ you had back in the day?  Yes!  Mechanical.  Current (rubber dome) keyboards didn't come to exist because they are better quality, better for your RSI/carpal tunnel, or even up to par with the mechanical keyboards.  They came to exist because they are cheap.

If you chose to use a membrane (rubber dome) keyboard, that is fine.  I am not trying to tell you to use a different keyboard.  My goal is to tell you there is an alternative, what the differences are, why it might be worth it to pay $40-$150 for a keyboard, and why mechanical keyboards are awesome.

In order to be able to explain the differences, I need to explain how a keyboard works.

I will assume that you already know some basic electronics and know what a circuit is.  You need a closed circuit for the electricity to flow through.  Well, keyboard switches work like regular switches in a circuit.  When you press a key, you close the circuit and you let the electricity flow through.

In membrane keyboards, the switches are rubber domes that are all part of a single rubber sheet.

You can imagine how consistent each key press will feel, depending on whether you are pressing another key at the same time and which key that is.  That's right!  It won't feel consistent.  Another flaw of the rubber dome switches is that you have to bottom them out (press them until they hit the bottom of the keyboard), otherwise they won't actuate (a key press won't get registered).  The PCB that has the traces that the rubber domes press on in order to make contact and close the circuit so a letter can show on your screen is actually a couple of nylon sheets.  The only actual PCB in there is the one of the controller.  You are generally limited to the keycaps (the plastic keys on your keyboard that press on the rubber dome and have a letter, digit, or symbol printed on them) that your keyboard came with.  The quality of the printing on them is low, usually done via a tiny sticker.  When it rubs out - because we all know it eventually will - you either need to buy ugly lettering stickers or find a place that can laser etch letters into the keys.

Topre, Alps, and Cherry are three famous types of mechanical keyboard switches.

I will only be talking about the Cherry type of switches however (specifically their MX variant), as they are the ones I am most familiar with.

In mechanical keyboards, each switch is separate.

The PCB is an actual PCB.  More often than not, you have a metal plate to which the switches are clipped for further stability.  Per key backlighting is lately most often RGB (meaning you can switch the color without the need to desolder the LED and solder another one in its place).  The key travel and force needed for actuation is a lot less than that on a membrane keyboard and you don't have to bottom out the keys for them to register if you don't want to.  Although you have a choice.  There are switches with different amounts of force required for actuation or a different distance it needs to travel before a keypress is registered.

There are countless options for keyboards and switches, so you can definitely find one that will suit your needs.  If, for some reason, you can't find a keyboard that you like or that fits your requirements, you can join the awesome world of custom mechanical keyboards.  There are tons of reading material online by people who have already built one.

Whether you are looking to buy a pre-made kit that you need to solder and assemble or you are looking to design your own PCB schematic, get it printed, design your own switch plate, get it laser cut, use switch "X" with the spring of switch "Y" and the stem of switch "Z", you can be sure there are many others who have already done that and can help you on your journey.

The Cherry Mechanical X-Point (MX) style switches can be from many different brands, not just by Cherry America (the original manufacturer, patent holder, and once the only maker of Cherry MX-type switches).

No matter which brand you choose though, you can always count on the size of the switch, the pin positions, and the switch stem to be the same.  What does that mean though?  We will discuss the switch internals and the design of mechanical keyboards in a bit, so some things may not make sense yet, but it tells us the following:

Let's say you just bought a shiny new keycaps set you spent $60 on, but your co-workers keep complaining about the loudness of your Blue switches or your PCB has died and you need to replace it.  You can count on the new PCB to work with your existing switches and your keycaps to work with your new switches.

The design/internals of a mechanical keyboard are as follows:

PCB

I think that's pretty obvious.

It has the circuit traces printed on it, the diodes that limit the direction in which the electricity flows so your NKRO (N-key rollover) can work, the keyboard chip, and the LEDs for that sweet RGB.  It is what you solder your switches to.  As mentioned before, you have the options of buying a pre-made keyboard, buying it as part as a kit, buying a PCB only and sourcing the other parts from an older keyboard, or designing your own and getting it manufactured.

Switches

The types of switches in the Cherry MX family can be as many as flavors of ice cream, depending on whether they are clicky and when the click comes, their force curve, their tactility or lack thereof.

However, they are generally divided into four types: linear, tactile, tactile clicky, and clicky.

Each switch is separate and consists of the following parts:

The Switch Stem - The part that the keycap sits on top of and slides down when you press it, making the two metal pins inside the switch touch and close the circuit.

The Two Metal Pins - Two metal pins, each having one of its ends part of a circuit that closes when they touch.  Simple, right?  It is.  However, they play a big part in the switch tactility.  Whether it will be clicky, tactile clicky, tactile, or linear.  They are actually a bit more than just pins.  What comes out of the switch is the pins part, but inside they are a little bigger.  Depending on switch type, the stem may or may not have a notch that touches against one of them, creating resistance on push, giving you the feeling of a "bump" and maybe that metallic "click."  There are different type of switches and some use a separate clicker.

The Switch Housing - Holds the switch together and may have a socket for an LED for backlight or a hole on the bottom to allow an SMD LED soldered to the PCB to fit under it.  Usually, the SMD compatible switches have a clear top housing to let the light shine through.

The Spring - It keeps the switch from staying in pressed position when you are not pressing it and creates resistance, which accounts for the force the switch needs to be pressed with in order for a key press to be registered.  You can either choose a switch that needs the amount of force you want or buy a separate spring and change the switch's spring to adjust the force needed.  They can either be plate mounted or PCB mounted.

Metal Plate

While among keyboard enthusiasts and custom keyboards you can see stuff like 5 mm thick plates made of acrylic, they are usually, at least on pre-made keyboards, made out of 1.5 mm thick steel or aluminum.

They provide further sturdiness to the keyboard, take the stress off the PCB, and - the main purpose - they hold the switches.  The reason for the 1.5 mm thickness is that, if you look closely at a switch, you will see the notches that clip to the metal plate.  The distance between the top and bottom notches is, well, 1.5 mm.

Depending on the switch hole's cutout, you may be able to open the switch housing without having to desolder it and remove it from the plate first.

Case

While you can see some very pretty cases, we won't talk about keyboard cases/housings, as there is nothing interesting about their design in general.  They just hold everything.

Keycaps

They are the plastic things that sit on top of switches, usually have letters written on them, and may or may not allow lighting to shine through the letters.

Before talking more about keycaps, I want to teach you about the different keyboard form factors so we can clear up some terms.

Some common keyboard form factors/sizes are 100 percent (regular keyboard, with number pad on the side), 80 percent (also known as TKL or "tenkeyless" - lacks the number pad on the right), and 60 percent (lacks the F row and everything to the right from the Enter key).

Some weirder sizes are 65 percent, which is pretty similar to 60 percent, but contains some extra keys - the arrows for example.

Then there are split keyboards where literally the two halves of the keyboard are separate.

Next, you have the layout of the keyboard: ANSI or ISO.

This relates more to the physical shape of the keys.  An ANSI full-size keyboard has 104 keys.  The Enter key is in a single row.  ISO, on the other hand, has a weird looking Enter key, a short left Shift, and an extra key between left Shift and Z.

Then come keycap profiles.  This is the general form factor of the keycaps - the way they curve between the different rows, their size, and curve per key.  For example, SA profile keycaps have a different curve and shape from DSA keycaps.

Then you have the keycaps material and printing or lack thereof.

You can have them made from PBT, ABS, or other materials.  The printing can either be done with stickers, like on membrane keyboards, by laser etching, by dye sublimation, or by double-shot injection molding where the letter and the keycap are two different pieces of plastic.  You can't feel the legend in double-shot injection molding and they won't wear out.  Most common places for legends to be printed on keycaps is either the top or the front (known as stealth or ninja printing) - or to have completely blank keycaps.  This article, for example, has been typed on a 65 percent keyboard, with SA profile keycaps which, with the exception of the left Shift, the right Alt, the Enter, and the Backspace keys, have nothing written on them at all.

You can also have artisan keycaps.

The name speaks for itself: keycaps made by an artist that can look like anything you imagine.  For example, my Esc key is a two-piece keycap that is an alien head.

Obviously, this article doesn't touch on everything.

Some parts have been more detailed while others have been less so.

I don't intend to make you a keyboard scientist, but only to introduce you and perhaps interest you in mechanical keyboards.  If you don't know if the hobby is for you, but want to see what all the fuss is about, you have two options: Buy a cheap mechanical keyboard for around (or less than) $50 or buy a switch tester so you can test the different types of switches before deciding which one you like.