Your Ultimate Guide to Membrane and Mechanical Keyboards

Keyboards are input devices found in various appliances and equipment but are commonly associated with computers. If you look around in online or physical shops, you will see several types of keyboards such as wireless, virtual, ergonomic, and flexible.

The most prominent types, however, are the membrane and mechanical keyboards. If you are not using a novel kind of keyboard, then there is a high chance that you are using either of the two.

Before explaining the differences between membrane and mechanical keyboards, let us first look into their similarity.

Inside the keyboard case, there is a circuit matrix connected to a controller. Each node in that circuit matrix corresponds to a key. In both types of keyboards, a keystroke is registered when a circuit is closed at a certain node, sending a signal to the controller then to the computer.

So, what are their differences?

Membrane and mechanical keyboards are characterized mainly by their ‘switches’, or the mechanism by which their circuits are closed. Other than that, there are also differences in their features and components.

We will go over the characteristics of each type to help you decide which keyboard is the right one for you.

MEMBRANE KEYBOARDS

Membrane keyboard on an ATM machine

Membrane keyboards are simpler than mechanical keyboards, especially in terms of materials. Hence, they are usually cheaper than mechanical ones.

To give you a better idea, here are the components of a membrane keyboard:

  1. Keycaps. These are the physical keys you see on your keyboard. Keycaps may be classified as high profile if they are tall, and low profile if they are short or slim. There are other more specific classifications, but these are the basics.
  2. Upper case. This usually contains keyholders or the shafts through which the keycap sliders go in.
  3. Dome switches. As mentioned earlier, the main difference between membrane and mechanical keyboards is their switches. Membrane keyboards have tiny rubber or silicon domes that are located above their respective nodes on the circuit. Pressing down a key puts pressure on the dome below the keycap. When the dome collapses, it adds pressure to the layers of membrane underneath.
  4. Membranes. Membrane keyboards have three layers of membrane. The top and bottom membrane layers are circuit films that complete each other when they come in contact. The middle layer is an insulator with holes. This separates the two layers of circuits and limits the contact only at the nodes. When the rubber dome is pressed down, the top film is pushed through the hole of the second layer, touching the bottom circuit film. This completes the circuit and registers the keystroke.
  5. Bottom case. The bottom case supports all these parts. Some bottom cases may also have a thin layer of foam inside to protect the membranes.

Simple but amazing, right?

While we are still on the topic of membrane keyboard components, let me give you a brief overview of a special kind of membrane keyboard — the scissor switch keyboard.

Scissor-switch keyboard

Scissor switch keyboards are usually found on laptops and low-profile (slim) keyboards.

They are also membrane keyboards that use rubber domes. However, instead of having sliders that go through keyholders, they have a scissor-like mechanism. This mechanism allows the keycaps to travel up and down at a shorter distance.

Customizability

When it comes to customizability, your choices are extremely limited for membrane keyboards. It is almost impossible to get customized keycaps for them.

The build of sliders and keyholders of every keyboard may be different for each model. Your best option is to take each keycap out and paint or dye each one. Also, there are replacement domes sold online — I think this could pass up as a slight ‘customization’.

What are the pros and cons of membrane keyboards?

I will not be putting a hard line between the pros and cons of membrane keyboards. When it comes to the typing experience, its features may be preferable for some.

Nevertheless, others may not be into these if they want more audible and tactile feedback while typing.

Membrane keyboards feel softer to press and are usually quieter than mechanical keyboards. This is because the rubber domes produce little to no sound when they collapse or rise. They also give off little to no tactile feedback.

Membrane keyboards are cheap, spill-resistant, lightweight, and more portable due to their materials, but their materials are also the sources of their disadvantages.

The rubber domes and membranes are prone to wear and tear. Although mechanical keyboards also wear over time, membrane keyboards may do so at a faster rate.

Another issue regarding membrane keyboards is their very minimal key rollover. Key rollover is the ability of the keyboard to correctly register multiple keystrokes when keys are pressed at the same time.

The N in NKRO or N-Key Rollover represents the maximum number of keys that may be registered when pressed at the same time. If an extra keystroke is registered when you do not fully press that specific key, it is referred to as ghosting.

Membrane keyboards used to support only 1KRO or 2KRO. This is a big problem especially if you are a gamer who uses multiple keys simultaneously in some games.

Technology improves over time, so there is hope that membrane keyboards may support higher NKROs in the future. Currently, high-end membrane keyboards such as the Razer Cynosa V2 and Logitech G213 may already have higher NKROs.

Membrane keyboards may sound bad because of the cons listed above. However, they may be the ones that fit your preferences when it comes to the typing experience. They are also more economical.

As I have mentioned earlier, technology is always improving and may give you more options in the future. Prolonging the life of your membrane keyboard will still depend on its quality and on how you take care of it.

MECHANICAL KEYBOARDS

Mechanical keyboard with DSA keycaps

Mechanical keyboards are more complex than membrane keyboards.

The keys of mechanical keyboards have their own switches. These switches are highly customizable to fit your needs, but they are also relatively more expensive than membrane keyboard dome switches.

To give you a better idea of how mechanical keyboards work, here are their parts and their respective functions:

  1. Keycaps. These are the keys you press on. Like membrane keyboard keycaps, these are also classified by their profiles. Keycaps have shafts underneath that attach to the stems of key switches.
  2. Key switches. These mechanical switches are responsible for completing a circuit in mechanical keyboards. Switches for long keys — spacebar, shift keys, enter key, etc. — have metal wires connecting two switches positioned at each end of a long key.

    Each switch has a stem and slider, housing, mechanical crosspoint, and spring. The stem is where the keycap is attached. It is connected to the slider, which has a protrusion(s) on the side. That protrusion is usually referred to as the leg, actuation point, or TLS (tactile, linear, and speed) surface on CherryMX switches.

    This protrusion separates the metal leaves of the crosspoint when a key is not pressed. When you press a key fully, the slider pushes the spring then moves down with the protrusion and past the crosspoint. This allows the metal leaves of the crosspoint to make contact.

    A crosspoint is a metal piece that allows the electric current for the actuation.

    The mechanical crosspoint extends out of the bottom housing and is already in contact with the PCB. Thus, when the leaves make contact, it completes the circuit and registers the keystroke.

    CherryMX has good visualization of this mechanism on their site.
  3. Mounting plate. This is where the switches are mounted. Plates support and keep the switches in place, but these are optional.
  4. PCB (Printed Circuit Board). The PCB is sturdier than membrane keyboard circuit films. Also, to reiterate, the circuit at a node is completed at the crosspoint of a switch instead of two touching circuit films.
  5. Case. This holds all the components above.

Customizability

Every part of a mechanical keyboard is customizable. If you are planning to build a mechanical keyboard, or just want to customize a certain part, it is important to know the size of your keyboard.

You may have seen percentages such as 60%, 65%, 100%, etc. A full-sized keyboard is 100%, but the size that is commonly customized is the 60% keyboard. If you buy only a set of 60% keycaps when you are building a 100% keyboard, you will lack keycaps for some keys.

Keycaps. Keycaps are sold in many colors and profiles. You should always check if the ones you have are compatible with your switches.

Key switches. As mentioned earlier, switches are highly customizable. We will be showing how switches are customizable by describing some Cherry MX switches.

Cherry MX is one of the most famous switches out there. Nonetheless, there are also other brands of switches such as NovelKeys, Kailh, and Gateron.

The stems of Cherry MX switches are color-coded to indicate the characteristics of a switch. Cherry MX reds are linear switches that have smooth TLS surfaces. This allows faster actuation, but less sensory feedback compared to the brown and blue Cherry MX switches.

Cherry MX browns are tactile switches due to the tactile bump on their TLS surface. When you press a key, there will be tactile feedback when the bump passes between the crosspoint leaves before the key bottoms out.

The Cherry MX blues also have a tactile bump, but it has two parts instead of just one. When the stem is pressed down, it hits the other part producing a click sound before bottoming out.

Those are just some of the Cherry MX switches. If you are interested to know more about their other switches, check out their site. Take note that other brands may have different color-coding schemes.

Different switches also have different actuation weights. The higher the weight, the higher the resistance of the spring is — more force is required for you to actuate a key. Also, remember to check if the switch you are buying is compatible with your PCB.

PCB. Like the other components, it is important to check the size of your PCB because the other components will depend on this. There are two types of PCBs: solderable and hot-swappable.

In solderable PCBs, you must solder each switch onto the PCB. If you want to replace a switch, you will have to desolder it from the PCB and solder the new one.

Hot swapping is replacing a component while the device is powered on. Hot-swappable PCBs have hot-swap sockets already attached to them. Kailh hot-swap socket is one common example. If you want to attach Kailh hot-swap sockets yourself, make sure to check if your PCB is compatible with it.

Mill-Max hot-swap sockets are another option if you want to turn any PCB hot-swappable. These are short and tiny tubes that you must solder onto your PCB. They are trickier to attach, but they are known to last longer than Kailh hot-swap sockets.

Case and Mounting Plate. These are also sold separately so they also have a lot of room for customization.

What are the pros and cons of mechanical keyboards?

The audible and tactile feedback provided by the membrane keyboard may be beneficial for those who type fast. The feedback gives an assurance that a key has been pressed.

Others may also just enjoy the typing sounds the clicky switches produce. However, these clicky sounds may not be so perfect in quiet workspaces or during lectures. You may put O Rings, something like a tiny rubber band, under your keycaps to lessen the noise. However, doing so may alter the typing feel.

Again, like membrane keyboards, these may have features that you prefer but others do not. The customizability of mechanical keyboards can give you the option to bring them closer to your preference. But, of course, you must shell out a few extra bucks.

Although each component can be bought separately, most of them are harder to manufacture and are pricier than membrane keyboard components. While they are more pricey, most mechanical keyboards are more durable than membrane keyboards.

Other things to consider about mechanical keyboards are their weight and NKRO.

Mechanical keyboards are heavier than membrane keyboards. That may lessen portability, but it is also a good feature if you want to keep your keyboard steady while typing. When it comes to key rollovers, most mechanical keyboards have higher NKROs than membrane keyboards.

SO, WHAT’S THE BETTER CHOICE?

If you prefer a softer and quieter typing experience, go for a membrane keyboard. If you enjoy typing sounds, and your work area is all right with it, go for mechanical.

If you want something cheap, go for membrane. If you want something that is heavy-duty and would last long, opt for a mechanical keyboard or a high-end membrane keyboard.

I hope this guide has equipped you with enough knowledge of how a keyboard works and what should be considered when choosing the right one for you.

There may be a lot more things to contemplate aside from those I have mentioned above. Even so, at the end of the day, it all boils down to the suitability of each keyboard to your circumstances, preferences, and purpose.

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