Introduction

As a Vim user (using VS Code with the Vim extension), I may have some bias in writing this article. Everyone has different preferences when it comes to keyboards, so please consider it accordingly.

One day in February of this year, I spent almost the entire day typing and coding on a mechanical keyboard (FILCO MANILA Air with Cherry MX Brown switches). I noticed that my fingers became quite fatigued and typing felt a bit weak.

Therefore, taking this opportunity, I decided to try the pinnacle of keyboards, and also a keyboard that many engineers dream of - the HHKB (Happy Hacking Keyboard). I have been using it since then and I am very satisfied with it. In this article, I will share my experience with the HHKB and also introduce the principles of a capacitive keyboard without physical contacts.

Keyboard Categories

First, let's briefly introduce the types of keyboards:

Membrane Keyboard

This is the kind of keyboard that can be bought for a few hundred dollars at a computer store. It is the cheapest design among keyboards. When a key is pressed, a conductive rubber contacts the circuit board, allowing the current to flow and the microcontroller inside the keyboard detects the change. Although convenient, the membrane loses its elasticity over time, and detecting multiple key presses can easily become inaccurate. For workers who need to use the keyboard for a long time, it may not be the best choice.

Mechanical Keyboard

The principle of a mechanical keyboard is similar to that of a membrane keyboard. When a key is pressed, the circuit is completed, allowing the microcontroller to detect the key press. However, the design of a mechanical keyboard involves springs, metal contacts, and switches. When a key is pressed, two metal contacts touch each other, completing the circuit. Depending on the type of switch, such as Blue, Red, Brown, or Black, each switch has a different feel. Mechanical keyboards also provide a stronger tactile feedback due to the presence of springs.

Capacitive Keyboard without Physical Contacts

Next is the star of today's discussion, the capacitive keyboard without physical contacts.

The principle of a capacitive keyboard without physical contacts is to detect key presses based on the change in capacitance. Two parallel electrode plates are placed, and these plates have the ability to store charge. By applying an appropriate voltage to the two electrode plates, the capacitors can be charged. The capacity of the capacitor is inversely proportional to the distance between the plates; the closer the distance, the larger the capacitance. A larger capacitance results in a higher voltage on the capacitor.

The microcontroller needs to use the Analog to Digital Converter (ADC) function to monitor the voltage changes. When the voltage exceeds a certain threshold, it is determined as a key press. It is important to note that the microcontroller does not directly monitor the capacitance change, but rather the voltage change.

The biggest difference between a capacitive keyboard without physical contacts and other keyboards is that it has no physical contacts and the circuit is always connected. Because there are no physical contacts, there is no component wear, the keyboard produces less sound, has a longer lifespan, and lacks the feeling of "clickiness".

It is worth emphasizing that the principle of the circuit being always connected does not affect the keyboard feel. The feel is determined by the design of the springs and silicone. Therefore, even with a capacitive keyboard without physical contacts, various keyboard feels can be achieved depending on the manufacturer's design.

Why are Capacitive Keyboards without Physical Contacts so Expensive?

Next, let's talk about why capacitive keyboards without physical contacts are so expensive. I think there are two main reasons: "fundamental differences in detection methods" and "manufacturing process".

Fundamental Differences in Detection Methods

As mentioned earlier, the main reason is the difference in principles. While regular keyboards only need to detect whether the circuit is connected, capacitive keyboards without physical contacts need to monitor the continuous changes in voltage to determine if a key is pressed. This makes the overall circuit and firmware design more complex.

In addition, the capacitance values of the electrode plates in a capacitive keyboard are typically in the range of a few picofarads ($10^{-12}$), and such small capacitance is easily affected by noise. Dealing with noise interference and avoiding false key presses requires careful consideration.

Manufacturing Process

The manufacturing process of capacitive keyboards without physical contacts is more complex compared to mechanical or membrane keyboards. It is necessary to ensure that the capacitance values of each key position are approximately the same, which requires more effort in the design of the circuit board. You can see the internal structure of the HHKB at 3 minutes and 42 seconds in this video.

(Additionally, the keyboard feel comes from the springs and rubber inside.)

Due to these reasons, there are fewer companies producing capacitive keyboards without physical contacts, and the prices are usually not low, which also attracts a smaller customer base.

Taking HHKB as an example, the highest-spec model, HHKB Professional HYBRID Type-S, costs around ¥35,200 (as of 2021, approximately $9,000 in Taiwanese dollars). A good keyboard can be used for several years, and some colleagues have been using their keyboards for decades, with the keyboards turning yellow. From a long-term usage perspective, this price is not expensive but rather an investment!

Currently, the most well-known brands in the keyboard industry are Realforce and HHKB. Recently, the Chinese brand Niz has also gained popularity, and their keyboards are relatively cheaper.

Although HHKB is relatively less known in the Taiwanese market, it is highly recognized in Japan. In the company where I work, there are over 100 people who use HHKB keyboards daily, not to mention those who use two HHKB keyboards.

HHKB (Happy Hacking Keyboard)

HHKB stands for Happy Hacking Keyboard. It was originally designed by Professor Eiichi Wada, an honorary professor at the University of Tokyo, in collaboration with the PFU Research Institute. The first version was released in 1996, and it is now celebrating its 25th anniversary in 2021.

The most famous quote about HHKB comes from its creator, Dr. Wada:

"In the American West, when a cowboy's horse dies, they leave the horse behind. No matter how far they walk through the desert, they carry their saddle. Horses are expendable, but the saddle is an interface that is familiar to their bodies. Nowadays, computers are expendable, but we must not forget that the keyboard is an important interface that can be used for a lifetime."

The PFU website also has an interesting article titled Please Pay Your Attention to the Keyboard Layout, which discusses why the HHKB layout is different from the standard keyboard layout. I recommend reading it!

HHKB Keyboard Layout

HHKB was originally designed for developers, and many of its key placements are optimized for efficient programming. However, even if you are not a developer, once you get used to the keyboard layout, you should be able to adapt to it. Developers, in particular, can feel the benefits of this layout more strongly.

The HHKB keyboard design aims for minimalism and removes all unnecessary keys, resulting in a keyboard with only 59 keys. From this image, you can also clearly see the differences between the HHKB layout and other keyboard layouts:

① Tab and Caps Lock in the Same Position

Caps Lock is not commonly used in programming (usually, uppercase is achieved by pressing Shift), but it occupies an important position on the keyboard. Therefore, the HHKB layout eliminates Caps Lock and places Tab in the same position. Pressing fn + Tab has the same effect as Caps Lock. This may not be very convenient for Mac users who usually use Caps Lock to switch input methods unless they only need to type in Chinese for work.

① Position of Ctrl

The Ctrl key is placed to the left of the A key. This requires some time to get used to, but once you become familiar with it, you will find that it is a great design. Your pinky finger does not need to make large movements, making it comfortable. It is convenient for navigating in Vim, such as using Ctrl+F, Ctrl+B, Ctrl+W for navigation, and Ctrl+C for closing programs in the terminal.

② No Arrow Keys

HHKB does not have dedicated arrow keys! To use the arrow keys, you need to press fn + arrow keys simultaneously or remap them using software. If you want to use the arrow keys on the keyboard for gaming, you need to make additional adjustments. I personally use my pinky finger to press the fn key and use the arrow keys for navigation, but it takes some time to adapt.

If you frequently use the arrow keys to move the cursor while programming, it may be more challenging because the pinky finger needs to press the fn key, which can easily cause fatigue. This was actually the reason why I started using Vim, and now I almost exclusively use hjkl for navigation.

② DELETE Above Enter

In a standard keyboard layout, there is usually a backslash above the Enter key. However, HHKB replaces it with DELETE (or backspace). The most noticeable benefit is that the distance your fingers need to move when pressing the backspace key is reduced.

③ Positions of \ and `

HHKB places these two keys above the DELETE key. It may take some time to get used to at first, but after a while, it feels okay. These two keys are not used as frequently.

The biggest advantage of becoming familiar with the HHKB layout is that you can feel a reduction in the stretch of your hands. For people who use the keyboard for a long time, the most efficient way is to move quickly on the keyboard while minimizing the distance traveled, which reduces fatigue over extended periods of use.

Typing Experience

For those accustomed to the feel of mechanical keyboards, the feel of a capacitive keyboard without physical contacts may initially feel strange or even unacceptable. Due to the lack of physical contacts, the capacitive keyboard does not have a strong tactile feedback or the audible clickiness of a mechanical keyboard. I recommend borrowing from a friend or trying it out in person before making a decision. After all, the feel is something that you can judge best for yourself.

Advantages

Suitable for Extended Use

Capacitive keyboards without physical contacts usually require lighter keypress force, making them suitable for people who need to type or code for long periods. After using a mechanical keyboard for a whole day, I felt noticeable finger fatigue, which led me to try the HHKB.

In terms of pure feel, I still think mechanical keyboards have a slight advantage. However, the HHKB has a unique feel that has a magical allure when placed on the desk.

Portable

The keyboard I am currently using weighs 540g and measures 30cm x 10cm, making it very suitable for carrying with a tablet or laptop.

Unique Keyboard Layout

Although it takes some time to get used to, once you become familiar with the HHKB layout, you will find that it makes programming much more comfortable. By reducing the use of arrow keys, I became more familiar with using Vim, which turned out to be a good thing.

Disadvantages

Unique Keycaps

The keycaps of regular mechanical keyboards usually use Cherry MX switches, but HHKB keycaps are produced by Topre and are not interchangeable. If you want to replace them with your favorite keycaps, you may need to put some effort into finding compatible options, and the selection may be limited. If you have access to a 3D printer, you can try printing your own keycaps, but the quality may vary.

Expensive

The price of these keyboards is not easy on the wallet. Apart from the keyboard itself, the prices of various accessories are also not cheap. When I received the keyboard, I realized that the HHKB itself does not come with a cover, and I had to spend ¥4,400 to buy the official cover. For the wooden wrist rest, although you can find cheaper options on Amazon, using the official wooden wrist rest also costs ¥4,400. Buying the keyboard itself and all the accessories can be a big hit to the wallet.

Battery Replacement

I personally prefer not to turn off the power, which may be why the battery consumption is faster. With daily usage of approximately 8 to 10 hours, I need to replace the battery about once a month.

Keyboard Layout

Once you become familiar with the HHKB layout, using another person's keyboard temporarily can be quite challenging and may require some time to adapt. Additionally, HHKB keyboards do not have dedicated F1 to F12 keys; you need to use the Fn key combination to access them. This can be a pain point for users who frequently use F1 to F12 as shortcuts. Personally, I like compact keyboards, so it's not a big issue for me.

Difficult to Purchase in Taiwan

There are almost no physical stores in Taiwan where you can directly purchase HHKB keyboards. You can only buy them through proxy purchasing or shipping services like Amazon Japan (Note: I heard that they no longer ship to Taiwan?). This also results in fewer discussions about HHKB in Taiwan. The most convenient and cost-effective way to purchase one is to buy it when you visit Japan. However, regular retail stores rarely sell HHKB keyboards. If you want to try them out in person, you can refer to the HHKB official website, which has showrooms in Tokyo, Osaka, and Nagoya.

HHKB Models

Currently, the HHKB series mainly includes three models: HHKB Professional HYBRID Type-S, HHKB Professional HYBRID, and HHKB Professional Classic. Each model is available in black and white, with engraved and unengraved versions. Let's briefly introduce each model:

Classic

This is the wired version of the HHKB keyboard and is also the cheapest model among the HHKB keyboards.

HYBRID

HYBRID means that the keyboard provides both Bluetooth and wired functions. The HHKB Professional HYBRID I am currently using can toggle between wireless and wired modes. This keyboard can pair with up to four Bluetooth devices, making it suitable for multi-device switching. For example, you can use it with a PC at the office, connect it to a laptop when working remotely, and connect it to your personal computer at home. Simply press fn + ctrl + a number key to switch, which is very convenient.

However, please note that the keyboard uses size 3 batteries and does not have a rechargeable function. Although rechargeable batteries can be used as a substitute, it can still be a hassle for users. Also, I feel that the battery consumption is a bit fast; I need to replace the batteries approximately once a month. This may be related to my habit of not turning off the power.

HYBRID Type-S

Type-S refers to the silent version. In addition to the Bluetooth and wired functions mentioned in the HYBRID model, the Type-S version has even quieter keypress sounds compared to the HYBRID version, although it is not completely silent. You can refer to this YouTube video (10 minutes and 12 seconds) to hear the difference in sound.

If you plan to purchase from PFU, remember to select the English layout for the keyboard, not the Japanese layout, as the two layouts are significantly different.

Conclusion

In conclusion, the feel of a keyboard is a highly subjective matter. Although I really like the feel of the HHKB, I understand that some people may find it unfamiliar. Especially for those who have used mechanical keyboards, the lack of tactile feedback in a keyboard without physical contacts can be a bigger difference than imagined. Therefore, I recommend trying it out before making a decision. With the recent depreciation of the Japanese yen, now might be the best time to make a purchase.

May you all find your favorite keyboard in the midst of the chaotic keyboard battle.

Other References

• Twitter Share: HHKB and ATM Keyboards in Japanese Dramas: This article mentions that the HHKB keyboard was used in a Japanese drama called "I Want to Leave on Time." The ATM keyboards in Japanese 7-Eleven stores are also capacitive keyboards without physical contacts.
• HHKB Pro2 Keyboard User Experience: One of the few Chinese articles about the HHKB user experience, although it is about an older model.
• HHKB Official Website: The official HHKB website regularly interviews well-known users and writes articles about them.
• HHKB's Birth Story (in Japanese): An article about the birth of HHKB.
• 散財TV - HHKB HYBRID Type-S Review (in Japanese): A review of the HHKB HYBRID Type-S by 散財TV.
• トバログ HHKB HYBRID Type-S vs. Previous Models (in Japanese): A comparison between the HHKB HYBRID Type-S and previous models by トバログ.

There are many more resources available in Japanese. Additionally, I think HHKB has done a great job with their Twitter account, where they interact with HHKB users almost every day, increasing the bond between users and the brand. They also leverage current trends to bring attention to HHKB.