A DIY accessibility switch for iPhone and iPad
Open Adaptive Switch is an open-source Bluetooth button for the iOS Switch Control accessibility feature. All of it is completely free: the firmware, the iPhone app, and the build guide are open source, so a switch can be changed to fit whatever a person needs. The hardware comes to around $15 in parts; comparable commercial switches sell for around $200.
The iOS app is on its way to the App Store. Everything already works today from the web setup page or a source build.
The app handles the fiddly part
Every setting lives on the switch itself and is changed over Bluetooth from the phone. No computer, no reflashing, and nothing is lost when the battery runs out or the firmware updates.
Any key, with modifiers
F13 to F24 pair cleanly with Switch Control, and letters, numbers, and common keys are in the list too. Custom key codes work as well.
Three actions from one button
Single key, tap or hold, or short, medium, and long presses. Each press length can send a different key.
A sleep timer that suits the day
The switch naps after a quiet stretch and wakes on the next press. On USB power it stays awake.
A name and color per switch
Rename each unit and give it a color in the app, so the red button on the tray shows up as a red button on the screen.
Battery numbers you can act on
Percentage, voltage, and charging state, live. The battery level even shows in the nearby list before you connect.
Firmware updates over the air
Install the latest release from the app, pick any published version, or roll back. Settings stay put through updates.
Made for iOS Switch Control
The switch shows up to iOS as a Bluetooth keyboard, so it pairs under Settings, Accessibility, Switch Control, the same place any commercial switch does. A press can tap the screen, run a recipe, or drive the scanner.
Each key registers as its own switch input, so three-action mode behaves like three switches in one box. A switch can also skip Switch Control entirely: set it to Space, pair it as a plain keyboard, and it play-pauses YouTube or Apple Music.
Several switches pair at once without colliding, and a switch keeps its iPad connection while a parent adjusts settings from a phone.
Apple's own guides cover the iOS side:
The hardware is four parts
A Seeed XIAO nRF52840 board, a momentary button, a small rechargeable battery, and a 3D printed button housing. The board holds its Bluetooth connection at roughly 0.1mA, which is why a charge lasts months. A new board is flashed once over USB; after that, every update arrives over Bluetooth. The build guide on GitHub covers parts, wiring, and flashing. The design is open, so any part can be swapped: a bigger button, a different housing, whatever the person using it needs.
Nothing to sign up for
The app has no accounts, no analytics, and no ads. Bluetooth traffic stays between the phone and the switch. The one outbound request checks GitHub for firmware releases, and it can be turned off. The privacy policy is one page.
Questions
What is an adaptive switch?
An adaptive switch is a button that gives someone with limited mobility a reliable way to control a device. On an iPhone or iPad, the Switch Control accessibility feature highlights items on screen and a switch press triggers them. It is standard assistive technology; the expensive part has always been the hardware.
Do I have to build the switch myself?
Yes. Assembly is wiring a button between two pins on the board and plugging in a battery; the guide on GitHub walks through it step by step.
What does it cost?
Around $15 per switch in parts. The board is around $10, and the button, battery, and printed housing make up the rest. The app and firmware are free, and there is nothing to subscribe to.
When does the app reach the App Store?
It is being prepared for the App Store now. Until it is published, the app builds from source with Xcode, and the web setup page does the same job from a browser.
Can I set up a switch without an iPhone?
Yes. The web setup page runs in Chrome or Edge on a computer or Android device and has the same controls. The switch itself pairs with anything that accepts a Bluetooth keyboard.
Does it work with Android?
The switch pairs with Android as a Bluetooth keyboard, but Android's Switch Access has not been tested with it yet. Reports are welcome on GitHub.
How long does the battery last?
Months of normal use per charge. The radio holds its connection at roughly 0.1mA, the sleep timer cuts that further, and charging is a gentle 50mA over USB-C.
Is any data collected?
No. The app has no accounts, no analytics, and no ads, and Bluetooth traffic stays between the phone and the switch. Its one outbound request, a check of GitHub for firmware releases, can be turned off.
Start with the build guide
Parts list, wiring, firmware, releases, and the app source are all in one repository. Questions and build reports are welcome.