Choosing Your Buttons

You will need to determine what type of button or buttons you want to use to activate the device. While it is possible to do switch control with a single switch, if the user is capable of pushing more than one button it will be much easier and faster. In single switch mode, iOS itself jumps from item to item and then you have to press a selection button to select that particular item. If you have 2 switches, one of them is used to manually advance the cursor to the next item while the other is used to actually select. Using three switches gives you the opportunity to scan forwards or backwards to the available options and not just continue to scan forward. The examples in this tutorial assume we are going to use three switches however we could use fewer or more depending on your needs and capabilities.

The type of switch that you use will depend upon the capabilities of your user.  For people with plenty of strength but a lack of control such as users with cerebral palsy or those recovering from stroke you might want to consider this a large red arcade button.

Large Arcade Button with LED - 60mm Red

PRODUCT ID: 1190
BAM! This 60mm diameter arcade button is large and inviting and ready for all sorts of pressing and pushing. We've seen these on some games of skill in arcades, they're easy to...
$5.95
IN STOCK

This is a 60 mm diameter button but there is also a 100 mm version and they come in not only red but, green, yellow, blue or white. If you want something a little smaller you might consider this 30 mm arcade style button.

Arcade Button - 30mm Translucent Red

PRODUCT ID: 473
A button is a button, and a switch is a switch, but these translucent arcade buttons are in a class of their own. They're the same size as common arcade controls (often referred to...
$5.95
IN STOCK

It also comes in a variety of colors.

Keep in mind that fingers, hands, elbows are not the only options available. The arcade style button could also be mounted on a wheelchair headrest to be pushed with your head.  You might want to consider a foot switch such as this one.

Foot switch

PRODUCT ID: 423
Your friends probably tell you that you are "good with your hands," but now you can also be good with your feet! This foot switch is made of rubbery plastic, is plenty strong...
$7.50
OUT OF STOCK

If the intended user has limited range of motion and possibly limited strength such as those with muscular dystrophy or ALS then you will probably want a smaller button with a soft touch. A variety of tactile pushbuttons are available from Adafruit such as these…

Colorful Square Tactile Button Switch Assortment - 15 pack

PRODUCT ID: 1010
Little clicky switches are standard input "buttons" on electronic projects. These work best in a PCB but can be...
$5.95
IN STOCK

Tactile Switch Buttons (12mm square, 6mm tall) x 10 pack

PRODUCT ID: 1119
Medium-sized clicky momentary switches are standard input "buttons" on electronic projects. These work best in a PCB but
$2.50
IN STOCK

Personally I have a type of muscular dystrophy known as Spinal Muscular Atrophy and I only have limited use of my right hand. I use micro switches similar to these

Micro Switch w/Wire - Three Terminals

PRODUCT ID: 820
Micro-switches are often found in arcade buttons and joysticks but they're also really handy in any kind of mechatronics project or when you need a basic sensor. They are always...
$2.95
IN STOCK

Micro Switch w/Roller Lever - Three Terminal

PRODUCT ID: 819
Micro-switches are often found in arcade buttons and joysticks but they're also really handy in any kind of mechatronics project or when you need a basic sensor. They are always...
$1.95
OUT OF STOCK

Here is a link to all of the buttons sold by Adafruit https://www.adafruit.com/categories/235 and all of the switches in the store https://www.adafruit.com/categories/155

Note that you want a momentary contact button or switch not a toggle switch, slide switch, or push off/push on power switch.

Although it's beyond the scope of this tutorial, you might want to use an analog joystick of some kind. There are several available in Adafruit store. You may not want an actual physical switch at all. Set up a photosensor and LED as if you pass your hand or finger between them it would break the beam and cause a signal to be sent to your Arduino. You could mount an accelerometer on a lever so that simply moving the position of the lever detects the change in angle. Alternatively you might want to consider some sort of capacitive touch solution. Here are a variety of capacitive touch devices available from Adafruit. https://www.adafruit.com/categories/60

Also most Arduino compatible devices can be wired up to detect capacitive touch with nothing but a resistor and two input pins as described in this tutorial.

https://learn.adafruit.com/capacitive-touch-with-conductive-fabric-and-flora/

Although that tutorial talks about the flora, the capacitive touch principle will work with most Arduino compatible AVR processors such as ATMega328 and ATMega 32u4. If you want to learn more about how capacitive touch devices work, we recommend this video "From the Desk of Lady Ada" where she describes capacitive touch in detail.

Professionally built adaptive technology devices refer to the switch devices as "AT Switches" for "Adaptive Technology Switches". The industry standard for connecting such devices is a 1/8 inch or 3.5 mm mono plug and jack. If you want your device to be compatible with this industry standard, you should put a 3.5 mm jack in your device and a 3.5 mm plug on your switch. Here are some sources Digi-Key. Similar devices may be available at your local RadioShack or other suppliers.

Digi-Key

arduino_3.5_mm_in-line_jack.jpg

In line jack

Digi-Key

arduino_3.5_mm_panel_jack.jpg

Panel mount jack

Digi-Key

arduino_3.5_mm_plug.jpg

In-line plug

Once you have selected the proper buttons, you need to consider where and how to mount them for the convenience of the user. If you have access to a 3D printer you may want to build a specialized enclosure for this project with the buttons mounted on the top. Here is a video from ATmakers.org that talks about how to mount commercially available AT switches on a standard camera mount. Use their solutions or use it to inspire you to create a mount of your own. https://youtu.be/Y-_8y-hHtM0

You may want to create a specialized piece to assist the user to hold onto micro switches in one hand. Here's a photo of a set of three micro switches in a 3D printed ring that helps me hold the buttons in my right hand where I can push the buttons with my thumb.

Each user will have different needs. You can use your maker skills to adapt and create something unique to the individual that may not be available in a commercially manufactured product.

This guide was first published on Feb 13, 2017. It was last updated on Nov 16, 2018. This page (Choosing Your Buttons) was last updated on Feb 09, 2017.