Background:

Operating computers and smartphones typically requires using a traditional input device like a mouse, keyboard, joystick, touch screen, or touch pad. However, this input methods can be difficult or even impossible to operate for some users, such as those with low hand dexterity or limited range of motion in their hands.  

There are a variety of adaptive switches that can be used as an alternative input method depending on the needs of the user, but they are often unable to connect directly to the host device and they require a device that can convert switch input signals to a compatible format acceptable by the host devices.  These devices commonly known as switch interfaces, convert adaptive switch enclosures to USB or Bluetooth human interface device or HID commands.

Project Information:

M5-Access-Switch-Input is a Bluetooth enabled Adaptive Switch Interface based on ESP32 M5StickC/M5StickCPlus, and the Switch Input module which offers up to two 3.5mm switch inputs.

M5-Access-Switch-Input aims to provide a more affordable and customizable switch interface alternative to available commercial switch interfaces. All the components can be purchased online, the custom PCB can be fabricated using online PCB fabrication services, and the enclosure files can be downloaded and 3D printed from project repository.

Usage:

M5-Access-Switch-Input allows the end user to connect up to two adaptive switches to their host device through two available 3.5mm stereo jacks. The switch interface can operate in multiple modes, and the end user can switch between the modes by simply holding and pressing Switch A for four seconds.

Features:

Battery and sleep mode:

M5-Access-Switch-Input uses an internal Lithium-ion battery which can provide 1.5 to 3 hours of power based on the usage. The sleep mode built-in to the device allows to save power when the device is not used.

Connection:

The device is connected to the host device through Bluetooth connection.

Modes:

The Adaptive Switch Interface supports the following switch modes:

• Switch Mode
• Switch Mac Mode
• Morse Keyboard Mode
• Media Control Mode
• Settings Mode

You can change the modes by holding switch number A or Button A for 4 seconds.

Instructions:

All the required assembly documentation, software, hardware are documented in the project github repository. All the necessary electronics for this project are listed and can be purchased online via provided hyperlinks in the bill of materials (BOM) file.

Compatibility:

M5-Access-Switch-Input can be used to interact with a host device and as a method of navigation through the user interface of following Operating systems:

• Android : You need to enable the Switch Access feature. This feature is called Universal Switch in Samsung devices.
• iOS: You need to enable the Switch Control feature.
• macOS: You need to enable the Switch Control feature.
• Windows: Windows doesn’t support switch interfaces by default, but additional third-party software can be installed to allow interacting with host device via adaptive switches.