Controlling a motorized wheelchair with your eyes


This DIY open source system enables those with ALS to drive their wheelchairs through eye movement.


Amyotrophic laterals sclerosis, more commonly known as ALS, is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, people may lose the ability to speak, eat, move and breathe.

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With that in mind, the Maker trio of Patrick Joyce, Steve Evans and David Hopkinson are currently working on a Hackaday Prize entry that will enable those with the disease, who no longer have use of hands, to operate their wheelchairs through eye movement. The project, called Eyedrivomaticconsists of a 3D-printed electronic hand that sits above the chair’s joystick and is given instructions by an Arduino Uno (ATmega328) based control unit, which in turn, commands the eye-tracking software.

ALS usually strikes people between the ages of 40 and 70, and approximately 20,000 people in the U.S. have the disease at any given time. The team ultimately hopes to provide an affordable and easily accessible method for those with motorized wheelchairs to take complete control of their mobility needs all through the power of sight.

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Though both Joyce and Evans have access to Eyegaze equipment, the eye-tracking technology is only capable of operating a computer, not a wheelchair. As a result, the Makers wanted to create a device that could interface with the wheelchair-mounted computer, and then physically move the wheelchair’s steering joystick.

“I envisaged having two parts: an electronic hand unit and a brain box to control it. Making the [hand] should be fairly easy using servo motors, but I was stuck on what the brain box would actually be… then I discovered Arduino,” Joyce explains.

After ordering a 3D printer and waiting for it to arrive, he sought the help of Tim Helps who already had access to a machine, which they used to make a first prototype based on an initial mockup housed inside a cardboard box. Yet, the team found this version to be a bit too complicated and required a lot of soldering and custom parts in order to piece together. With a functioning proof-of-concept, a 3D printer on hand and a little help from the kind folks at 3D Systems, the Makers went on to build a second iteration of the Eyedrivomatic. This time, though, without the need of soldering and a wide range of components.

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“Initially, I thought we’d interface the computer with the brain box via infrared, as most wheelchair mounted computers have infrared environmental control, but after consulting Steve I dropped this in favor of a direct connection via USB and got busy writing software for it in Processing,” Joyce adds.

When all is said and done, this DIY system is an inexpensive, open source way to give mobility back to people who thought they had lost it forever. Following a successful live test of Eyedrivomatic, the team has proceeded to develop a switch version employing Eyegaze for selecting direction and speed, and a switch for accelerating and stopping.

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“It was very exciting, with everything working reliably and well. I will have to tweak the software a bit as the diagonal speed was disproportionately fast. With that done, the chair should change direction and speed smoothly in mid flow,” Joyce notes.

Now, the Makers have moved on to their latest model, which includes updated software, control box and electronic hand — all with the goal of making it easier to build. By November, the trio hopes to have a couple of next-generation Eyedrivomatics in use by ALS sufferers along with comprehensive set of instructions available online.

This is truly amazing and is exactly what this year’s Hackaday Prize challenge is all about. You can read more on the project’s official page, as well as check out the machine in action below!

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