Interview: Aimpad Founder On Analog Keyboard Switches

One of the more exciting developments in the keyboard world, at least as it pertains to gaming, is analog switches. Yes, analog, just like the technology you find in gamepads. Those joysticks on your Xbox controller? Analog. The keys on almost every keyboard on the market today? Not analog.

Simply put, standard keyboards perform a basic on/off function: Press the key down, the command is sent, release the key, the command ceases. This makes the most sense in typing, where you always want one key press to equal one letter on the screen, but in games, that’s not always so ideal. If, for example, you want your character to move from Point A to Point B, you might to walk slowly, or jog, or run quickly; but with standard keyboards, you get only one speed.

By contrast, analog switches give you the ability to move at gradations of speed, just like a joystick can. If you think about it, analog switch keyboards could become gamers’ most indispensible weapon of choice.

There are precious few people actually working on developing analog keyboards; one is Wooting, a small outfit we’ve written about multiple times, but another is Aimpad, which is a small team that has been working on an analog keyboard for even longer.

We sat down with Aimpad’s founder, Lance Madsen, to learn more about what Aimpad is trying to accomplish and how its technology works.

Tom’s Hardware: Why did you decide to start making analog switch keyboards?

Lance Madsen: Generally speaking, keyboards have not changed in decades. Adding fancy lights, and macro keys, and a way to disable the Windows key does not make a normal boring keyboard suddenly a "gaming" keyboard. A gaming keyboard should actually enhance the gaming experience over a "normal" keyboard. I strongly feel this type of technology is the future of gaming keyboards.

TH: Tell us about Aimpad--who are the parties involved?

LM: There are three engineering folks involved with Aimpad. One has primarily done circuit, PCB design, and mechanical placement; [there’s] another that has primarily done firmware design; and the third is me [who] does... basically everything else. The other members of Aimpad provide business management and financial support.

TH: What are you trying to accomplish?

LM: The whole objective of the company was to develop and basically fine-tune the technology around analog gaming keyboards. We started about five years ago to develop this technology, and we patented it. Basically, [we have tried to] get to the point where it’s cheap enough and easy enough to implement it in mechanical keyboards and then license it to companies that are already making keyboards--and just basically augment what they’ve already developed and add to the technology they have.

TH: Tell me how you’re implementing this? You’re using light sensors, right?

LM: Yeah, so there are infrared sensors that bounce an infrared signal off of part of the switch, and based on how far down the switch is pressed, it increases or decreases the analog signal.

TH: Is this something that can just be added onto any existing keyboard? You’re not making keyboards, you’re not making switches, you’re making this other Thing. So what is that?

LM: The other Thing is basically the PCB design and mounting position of the sensor, and then the firmware that’s involved to generate meaningful use cases using these types of switches.

TH: It looks like you’re focusing on the WASD keys only, is that right?

LM: The current one has 12 analog keys: It’s QWER, ESDF, and then the four arrow keys.

TH: You have to press two keys to move?

LM: No; basically, if you were to take an Xbox 360 controller apart--the left stick of an Xbox controller is just two potentiometers that are situated so that they rotate as you move that thumbstick around. So there’s two components: There’s an X and a Y coordinate that’s basically passed to a game that says, “I”m moving in this direction at this speed.” So we do the exact same thing using two keys, because if you push the W key in, say, 90% of the way, and the D key 20% of the way, you’re going to be moving at an angle at, like, 95 degrees at a speed of 90%, so to speak.

All we do is, using the WASD keys, based on how you use each of those four keys in combination with each other, [we plot] it on an X/Y coordinate and then pass that to the game, just like an Xbox 360 controller would.

TH: So let’s say I have the pedal to the metal on my W key; I can still adjust my left or right speed.

LM: Exactly, right.

TH: So there’s sort of two degrees of freedom…

LM: If you use all the keys we have, and the mouse at the same time, it gives you six degrees of freedom.

TH: What stage are you guys at now? Do you need to get keyboard makers on board so that you can sell them that part of the technology, or…?

LM: We have lots of ideas of what we want to do, and what we’ve been working towards. Trying to partner with big companies is difficult--with any technology. Basically, unless they’re motivated to do it, if they’re at the risk of losing market share, they’re not really willing to change what they’re doing. If nobody wants to take a leap of faith and have us work with them to develop the technology in their existing keyboards, then we’ll just make it ourselves.

The state of the keyboard that we have right now--it’s completely fully functional.

TH: You have the hard parts done, right, like the PCB and the firmware and the lights...and after that it’s just commodity pieces, right?

LM: Exactly.

TH: Chassis and switches, [just] pop them on there. Are the switches PCB-mounted?

LM: Yeah, they’re PCB-mounted.

TH: Do you feel like the hard part of the technology is done? You’ve done the testing, you know it works, and you just need to stick it on a keyboard? Is that about where you’re at?

LM: Yep. Exactly.

TH: With your technology, you can actually use the pretravel [for movement]. So you have that little 2mm of looseness where you can be walking, let’s say, and then you when you get past the actuation point, you can be running or something like that.

LM: Yeah, exactly.

TH: That’s an interesting take on it, because the one thing I’m worried about with Wooting’s solution [which originally could engage analog functions 2mm into the travel] is that I always had to have my finger depressed a little bit, and it was a little tiring to be balancing in the middle of the keytravel. I had that 60 grams of force pushing back on my finger at all times.

LM: Right. A good user experience is basically: Your finger should just rest on top of the key, and if you want to move a small amount, you just move your finger down a small amount, and you start moving, immediately, from moving your finger down. You don’t want to have a person guess, “Well, my finger’s resting on top of the key, I need to push it down--okay, now I’m starting to move.” That’s a huge disconnect from what you want to happen and what actually is happening. And it’s a really big flaw [laughs].

We’ve demoed this to hundreds of people. Some of our initial prototypes did that same thing, and they were all saying, “It needs to respond at the very top of the press.” So we spent a lot of time making sure that could happen.

TH: Would you stick with linear keys, or does it seem to work okay with Brown [tactile] switches, or even Blue [clicky] switches?

LM: You could definitely use [non-linear switches], but the best user experience would be linear.

TH: Right--you could use it with any [switch] I guess, really. I’m just thinking in terms of...if the pretravel [the function] is walking and past the bump [the function] is running or something. That actually brings up a good question: Theoretically, do you even need key caps? I mean, is this the kind of technology that I could hover my fingers over the lights and actuate?

LM: Absolutely.

TH: Wooting uses Flaretech’s optical switches, but you have keyboards with just regular Cherry MX RGB switches. How does that work? Can your version of this tech can work with essentially any regular mechanical switch?

LM: We use a patented process of sensing the switch position through the switch housing. If you look at a Cherry MX RGB switch from the bottom and press the stem, you can see the stem moving. We mount a sensor below the switch and shine an infrared LED at the stem.  As the stem is pressed down, more light is reflected back at a phototransistor, and this provides a wide range of analog values from the very top of the key press to the very bottom.  

As long as the housing of the switch is transparent to infrared light, and the stem is capable of reflecting infrared light, it will work. I have validated Cherry, Gateron, Zealios, and Matias mechanical switches.

As the sensing is done optically, it doesn't require the switch to be soldered to the PCB, and you can actually "hot swap" different switches. This would allow you to use, for example, clicky switches, or tactile switches, or ones with stiffer springs, or smoother presses, all without having to desolder anything.  I recommend linear switches for the most consistent performance for analog sensing, but there is not much stopping an enthusiast from using anything they would like.