Eelke Folmer

Human Computer Interaction Research University of Nevada, Reno

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Based on our experiences with making games one switch accessible we identified that the overall strategy is to apply a combination of strategies with the overall aim to reduce the amount of input that the player needs to provide. We identified three different strategies:

1. Automate: the input that needs to be provided. For example for a first person shooter this can vary from automatically picking up ammo or aiming to automating a user's movement by placing the user on top of a bot.
2. Remove: the input that needs to be provided. Instead of automating input one can also leave out functionality. For example in the one switch first person shooter we do not allow the user to switch weapons manually but switch the weapon when the ammo runs out.
3. Scanning mechanisms allows the user to provide a larger amount of input at the cost of a slower rate of input. Scanning basically breaks up the interaction of a game into chunks and adds them to a chain. The game will iterate over each element of the chain allowing the user to select the selected input. However it can be tricky to apply this mechanism to time sensitive games and it may also increase the cognitive load. Linear or Row/Column are typical scanning methods for on screen keyboards. For bejewelled and Monkey ball we implemented a rotary scanning mechanism which is faster, though it may be a bit more challenging to select gems on the edge.

One Switch Games

	Match 3 Game This popular puzzle genre of games has been made popular by the success of Bejeweled. The objective of this game is to swap one gem with an adjacent gem to form a horizontal or vertical chain of three or more gems ("match 3"). Typically users interact with such games using analog input such as a mouse. We implemented a rotary scanning mechanism that allows the user to select a gem in three steps. A prototype can be downloaded here (Windows only). You can also watch a video of the scanning mechanism.
	First Person Shooter First person shooters have been popularized by the success of games like Doom. These games typically feature a first person view and require the player to navigate their character using the arrow keys and aim their gun with the mouse. For the multiplayer version of the popular Half life 2 shooter we developed a modification that automates navigation as well as aiming allowing this game to be played with one switch input. Download the modification here (requires a copy of Half life 2) or look at a video of the prototype here.
	Monkey Ball Monkey Ball is a popular game genre involving tilting a platform in such a way that you roll a ball in a certain direction to avoid obstacles and collect coins. We modified an open source version of this game called Neverball and made it one switch accessible by applying a two step scanning mechanism. Download the one switch version of Neverball here (windows only).

The one-switch website run by my friend Barrie Ellis lists about 70 arcade-style one-switch games, all of which can be downloaded for free.