Affordable Raspberry Pi-Based Voice Control for Powered Wheelchairs

Powered wheelchairs are, without a doubt, some of the most life-changing solutions available to those living with physical disabilities affecting their mobility. They let people move around without direct assistance from a caregiver so that they can retain a high degree of independence. But if a person’s disabilities affect their arms or head, a powered wheelchair may not even be a practical option. Bernie was in that situation and struggling with his wheelchair, so his friend Drew Welsh constructed a low-cost, Raspberry Pi-based voice control system to help.

Bernie suffered an injury more than 40 years ago that left him confined to a powered wheelchair. While Bernie is mostly immobile, he does have a small amount of control over his right hand and that has let him control his wheelchair’s joystick. However, it has been difficult for Bernie to switch between modes in order to change position and alleviate pressure. Existing solutions on the market weren’t working, but Bernie has a strong and clear voice. That gave Drew the opportunity to add voice control capability to Bernie’s wheelchair, increasing his comfort and independence.

Drew’s three biggest priorities were ease of use, cost, and compatibility. A wheelchair like the one Bernie uses is a very expensive piece of equipment and Drew couldn’t just go hacking into it — especially not while Bernie was using it. So, Drew designed this solution so that it could attach to this wheelchair (and others like it) without permanent modification. It simply presses the buttons that are already there. It is also easy for Bernie to use and very affordable compared to other medical devices in this industry.

This system uses a Raspberry Pi 4 Model B single-board computer to listen to and recognize commands spoken by Bernie. Drew doesn’t state which voice recognition service he used, but there are several options available — including open source services that run locally without the need for an internet connection.

Once the Raspberry Pi recognizes a command, it activates a corresponding servo motor that pushes a button on the wheelchair. So, if Bernie says “check one,” the Raspberry Pi will use a servo motor to push the first button on the wheelchair’s control panel. This lets Bernie switch between modes and activate specific functions, so he can recline and alleviate pressure whenever he wants. Power comes from a standard USB battery bank, so there isn’t anything proprietary that would be difficult to replace.

This may be tailored to Bernie’s specific situation, but that’s the point. Many people find that existing solutions fall short and need something customized to fit their needs. Drew is a freelance robotics engineer and plans to help others, so check out his website if you or someone you know could use his services.