When a device goes into our assistive device library, it’s the culmination of a process that spans from coming up with an idea to designing a prototype to user-testing and refining it before we actually publish it.

And once the device makes it into the library, we’re still working with users and disability professionals to continually improve and enhance the device. Sometimes they modify the devices themselves to fit their own needs.

A great example of this is the Light Proximity Switch.

Top: A hand waves over the proximity switch; Bottom Left: The sensor outside the casing; Bottom Right: A patient uses a the Light Proximity Switch.
Top: A hand waves over the proximity switch; Bottom Left: The sensor outside the casing; Bottom Right: A patient uses a modified Light Proximity Switch.

It started out as a request for a cost-effective alternative to commercially available proximity switches — switches you don’t have to touch to activate — which typically go for more than $250. These are great for people that have difficulty exerting force on other types of switches, or have difficulty precisely targeting the button.

So we went to work and came up with a few prototypes, and we sent them out to a number of testers.

One of our partners in this avenue is the Sunny Hill Health Centre at BC Children’s Hospital. They’re always looking for ways to help their patients, and are glad to receive assistive devices to allow kids to use toys and to play.

While early versions of our proximity switch focused on hand movements like waving your hand over the sensor, what they found at Sunny Hill is that they needed a device for people with low finger strength, one that could be activated by finger movements of only a millimeter.

An early prototype of the Light Proximity Switch.
An early prototype of the Light Proximity Switch.

We went back to work, designing an enclosure that makes it easier for users to switch between two modes — larger movements like waving your hand, and small finger movements.

“It’s not just the user we’re thinking about when we’re designing these devices, we also invest a lot of time and effort in making sure makers of varying skill levels can build these devices, from the design of how it’s put together to the instructions the maker will use. We rely on volunteers being able to successfully build them, so it’s an important consideration.”

Based on testing feedback, we modified the circuit board to make it easier to assemble, and we added additional controls to make it easier for users to adjust.

In April 2020, after doing more testing and having conducted test builds to ensure that it’s easily makeable, we published it in our assistive device library.

This one costs about $20 in materials — compared to the $250 or more for a commercial device — and can be built in an hour. It’s very low powered, meaning you’ll get months on the coin cell battery powering it.

Since adding it to our library, we’ve been working with Sunny Hill to guide modifications to the proximity switch design for use by their patients.

A patient at Sunny Hill trying out a modified light proximity switch to control their communication device.

In these modifications, the sensor has been taken out of the main unit and is mounted separately.

The results are promising. For one patient who used the device recently, it was the first time they ever used their right hand to access a switch.

Another idea we’re looking at is possibly making the switch work in the inverse manner, having the user keep their finger on the switch and activating it by moving their finger away.

It’s a good example of the fact that once something goes in our assistive device library, it’s not necessarily the final iteration — it’s not there to stay static.

We don’t just allow people to modify our designs, we encourage it. Everything you need to make the Light Proximity Switch (and all of our devices), along with all of the files that were used to design it are all available to download. We want to make sure that someone like Sunny Hill has access to them and can improve upon it, and we can incorporate those improvements going forward.

Ultimately the goal is to end up with the best possible device.