Users with special needs use a wide variety of inputs to act with their devices and environment. The control interface and its suitability to the users possibilities is essential when you have a disability. It conditions the effective use of the assistive device whatever its nature (wheelchair, computers, call bell...) For gaming purposes most commons and usefuls interfaces are switches and joysticks.
The switch is a momentary push button which closes an electrical circuit which will be detected by the device to be used. In game, it can replace the direct press on a button on the controller. It has a 3.5 mono male jack connector and the device must be equipped with a 3.5 mono female jack
There are different types of switch which have different sizes and sensitivity and adapt to many motor possibilities. They are placed opposite in a zone or a reliable, repeatable and non-fooling movement. Typically, they can be installed near the hand, a finger, but it can also be at the head or anywhere else where the user can produce an exploitable movement.
Joysticks are used as interface to produce movement in game, there are numerous in type, shape, sensitivity, connectivity and activation force. Typically additional joysticks are set up on a table or a specific mounting system to fit users needs and possibilities.
It is also possible to use the power wheelchair's joystick as a stick in game. With bluetooth connectivity if the wheelchair is equiped and a specific device the TITAN or TITAN 2. This device allow you to recover the mouse signal from a wheelchair joystick equipped with bluetooth but it requires a computer and a dedicated software to be programmed.
Or with an extra hardware which detect the movement made on the joystick and translate it in stick signal : JoytoJoy
For more info on adaptive gaming joysticks, read the nice MakerMakingChange joysticks documentation
To play video game with these types of specific inputs, you have to use a dedicated interface which act as a gateway between the interface devices and the videogame console.
The arrival on the market of Microsoft's Xbox Adpative Controller (XAC) was a big revolution and made life easier for many gamers by offering many possibilities to adapt external switches and joysticks to a console for a price comparable to a standard game controller ($99).
This aid works perfectly on PC and Xbox, and could also adapts to other consoles (like Nintendo Switch and Playstation) buy buying a specific conversion adapters.
The Hori Flex controller that recently arrived on the market is a similar aid that allow to play with assistive external devices on a Nintendo switch, for a $249 cost.
The disadvantage of this solution is the compatibility with different joystick, only a few available on the assistive device market are compatible and work properly with the hori flex.
To play on Playstation, there isn't dedicated solution yet, and Sony has recently announced working on a adaptive gaming hub call project Leonardo but its still in developement.
Another problem, common to Xbox adptive and hori flex is that they don't allow the connection with specific control interfaces for power wheelchairs inputs such as joysticks with serial connection (sub D9) . It's however a standard in assistive devices field.
Considering these issues, a high price for a game accessory, limited cross-platform compatibility and limits in connection possibilities, we thought it might be interesting to solve these problems with a little bit of open source, co-design and digital fabrication.