Directional pad
A directional pad, usually abbreviated to D-pad, is a control device used to input directional movement to a game device. It was created in 1979 by Tiger Electronics and first used on their handheld game Playmaker released in 1980. The D-pad serves a purpose similar to the digital four-way joystick, but was designed to work with handheld devices. The most common layout is cross-shaped with four physical switches to accept input for up, down, left, and right directions. A D-pad has a pivot point beneath it causing it to tilt over its center when the directions are pressed. This prevents opposite directions from being pressed simultaneously while also allowing up two neighboring directions to be pressed at the same time, making it possible for eight total directions to be inferred from the four-way input. Since the early 1980s, the D-pad is become the most common directional input device for handheld controllers.
Personal
My first video game console was an Atari 2600, so I spent my first couple years gaming on a joystick. I saw an NES around 1987, but I don't think I played it. When I was talking about video games with an elementary classmate, I told him about my Atari, and he told me about his console, a Master System. I went to his house and he showed me Wonder Boy. I think this was the first time I used a controller with a D-pad. In 1988, my brother and I bought an NES, which we played constantly, causing me to develop callouses from the D-pad. The D-pad has since become my favorite directional input device.
History
Early video games used a variety of input devices. The pre-commercial video game Tennis for Two (1958) used rotational dials, an input system that would see much use in the 1970s thanks to the Magnavox Odyssey and Pong. For Spacewar! (1962), players used push-buttons to rotate their space ships, and so did the unlicensed commercial version made by Atari, Computer Space (1971). Later arcade titles like Space Invaders (1978) also used buttons for players to move their spaceship left and right, while Blockade (1976), used four separate buttons to move the player's character up, down, left, and right. However, Galaxy Game (1971), the second commercial arcade game and another unlicensed version Spacewar! took a different approach and used a four-way digital joystick, a control system that would eventually give rise to the 8-way joystick which became the most popular directional input device in the arcade as well as one of the primary controllers for the Atari 2600 in 1977.
However, the D-pad didn't make a showing in any of these early video game systems: not in the arcade, home consoles, or home computers. The single-piece cross-shaped directional pad was in fact initially created for handheld games where the player was expected to hold the entire unit. A device like the Atari joystick was fine when held by two hands, but the rectangular display on many early hand held games meant that operating them with joystick would be impractical, while the D-pad can simply be operated with a thumb. The D-pad is additionally effective in handheld devices because its low-profile makes it more compact and less likely to catch on something and break off.
The D-pad as we know it today, a single four-way directional button with a pivot, was invented by William F. Palisek at Tiger Electronics who filed a patent for his invention on 1979-08-27. The first game to use it was the Tiger Electronics Playmaker released in 1980, with Palisek's patent being granted on 1981-03-17. A circular D-pad design was later used on the Tomytronic TRON in 1981.
In 1982, Ichiro Shira created a variation of the D-pad for Nintendo's Game & Watch version of Donkey Kong. This same D-pad that was used for the Famicom Controllers released on 1983-07-15. Many amateur historians erroneously credit Nintendo with the invention of the D-pad, specifically Gunpei Yokoi, because he oversaw the development of the Game & Watch. However, Nintendo didn't patent their version of the D-pad until they started creating the Nintendo Entertainment System. Being a company that also produced handheld video games, it's probable they already knew of the existence of the Playmaker and knew they wouldn't be able to patent the existing tech, or feared they might get sued for patent infringement if they tried. However, on 1985-08-09, a couple months before the first US test release of the NES, Nintendo filed a patent for their version of the D-pad, and properly cited Palisek's 1979 patent as prior art. I don't understand patent law enough to know why Shira's design was different enough from Palisek's to warrant a new patent, but Nintendo's patent was granted on 1987-08-18.
The control panel of Tomytronic TRON (1981).
Nintendo Game & Watch Donkey Kong (1982).
The Famicom Controller (1983) which made the D-pad popular.
The Epoch Game Pocket Computer (1984) also had a D-pad.
Nintendo patented their D-pad just prior to the release of the NES and its NES Controller (1985).
Interestingly, none of the early games which used a D-pad took advantage of its ability to infer eight-way movement. All of the first handhelds were too primitive to need diagonal movement, and the first nine games released on the Famicom didn't use diagonal movement either, primarily because most were ports or variations of arcade games which were designed without diagonal movement. As far as I can tell, the first video game to use eight-way movement with a D-pad was Nintendo's Tennis, first released in January 1984. Of course, this wasn't much of a milestone, since digital joysticks had already been interpolating eight directions on a four-direction digital joystick for years.
The unprecedented success of the Famicom caused nearly every subsequent console to use a D-pad on their controllers. However, to prevent having to pay patent royalties to Tiger Electronics or Nintendo, most manufacturers made slight modifications to the design of their D-pads and filed their own patents. Tiger Electronics' patent expired on 1999-08-27, and Nintendo's on 2004-08-18, so D-pads can be made with those simpler designs without having to pay royalties, and D-pads now show up all over the place like on remote controls, early cell phones, digital cameras, printers, and the like.
Throughout the second half of the 1980s, and most of the 1990s, the D-pad was the primary directional input system for home video game consoles. However, in 1996, Nintendo re-popularized older analog joystick technology for the Nintendo 64, and Sega and Sony followed suit. However, the analog joystick didn't replace the D-pad, manufacturers added the analog joystick and retained the D-pad on all of their most popular controllers. To this day, most consoles continue to have a D-pad on their controllers.
Technical
D-pads are composed of five key elements: a directional button, a pivot, a silicone membrane, a circuit board, and a case.
The hard plastic D-pad button. This is the underside of a PlayStation Dual Shock D-pad. Note the four nubs for each direction, and the rounded center pivot nub.
The silicone membrane of a PlayStation 4 Controller. There is a dome for each direction and black conductive material on the underside of each.
The Genesis Controller put the pivot in the membrane to avoid paying patent royalties.
The circuit board of an NES Controller. Each trace has a gap.
The plastic case of a Super Famicom Controller keeps the internal pieces in place.
The plastic directional button is simply a piece of molded hard plastic. It's typically cross-shaped on the top, has four small nubs on the underside corresponding to each of the four directions, and a larger rounded pivot nub on the underside in the middle to let the d-pad button rock back and forth when the player presses on it. The directional button sits upon a silicone membrane which has four domes which, when depressed with enough force, will pop down, and, when force is released, will pop back up. On the underside of each dome is conductive material which will connect with the circuit board beneath it. The circuit board contains traces leading to each of the four directions with a gap in the trace directly below where the domes in the silicone membrane sit. When the player pushes down on the d-pad button with enough force, it depresses the dome of the silicone membrane, and the conductive material connects with the circuit board closing the electric circuit. Once the circuit is closed, a message is sent from the controller to the video game platform telling it which direction has been pressed.
Although Tiger Electronics held the initial patent for the D-pad, companies got around having to pay royalties by making minor modifications to the invention and patenting their own versions. This has led to every major video game company engineering a slightly unique D-pad. Nintendo filed their own patent based on the design used in the Game & Watch Donkey Kong. Sega developed at least two different methods. Their initial Genesis Controller has a metal ball in the silicone membrane to serve as a pivot while their later Genesis models, as well as the Saturn Controller, moved the pivot from the center to a exterior of D-pad which functions like a large pivot. Sony designed their initial PlayStation Controller with a plastic pivot which was detached from the D-pad button.
The pivot on the D-pad not only allows the button to rock, allowing the player to push two neighboring directions at the same time yielding diagonal directions, but it also physically prevents opposite directions from being pressed by the player. Because opposite directions can't normally be pressed simultaneously, many games are programmed under the assumption that it will never happen and the game is not programmed to prevent it. Because of this, game hackers sometimes use modified controllers which allow opposite directions to be pressed at the same time in order to find exploits in the games. This is a common practice in the tool-assisted speed run community, and often leads to interesting glitches.
Media
Documentation
Patent application for Tiger Electronics' D-pad (1979).
Patent application for Nintendo's D-pad (1985).
Patent application for Atari's Lynx D-pad (1991).
Patent application for Sega's D-pad (1993).
Patent application for Sega's improved D-pad (1993).
Patent application for Sony's PlayStation controller (1995).
Videos
Links
