Hand-Powered Mobility Device

Designers: Min Choo, Olivia Hao He, Arjun Kalyanpur, Audry Kang

Supervising Professor: Larry Bohs


Children with spina bifida experience partial or complete paralysis of the lower extremities, often requiring an upper extremity powered mobility device in order to travel. In the United States, these devices are either easy to purchase at a local store or to build using a variety of commonly found materials. In countries like Kenya, however, materials are both scarce and expensive given the average income. As a result, young children in Kenya with spina bifida often rely on oversized wheelchairs, if any mobility device at all, to move around. The goal of this project was to develop a hand powered mobility device sized for children aged 2-5 years old that was cheaper than current alternatives, and that could be easily constructed from materials found in Kenya. The device features wheels that children can spin by hand to propel themselves, as well as a reclining seatback that allows the child to lie down while moving.. Using this hand powered mobility device provides young children with spina bifida a more convenient, fun, affordable and easier-to-use mobility device to travel in.


The device provides a durable, sustainable, and low-cost mobility solution for Kenyan children with spina bifida. By providing them with the ability to travel independently, this chair allows children to comfortably navigate their homes and engage in their communities. During testing with a local client with spina bifida, the client’s mother commented, “This device is safe and is easy for my son to turn. I think the wheels work better than his [expensive] wheelchair.”


The Hand-Powered Mobility Device has three main technical features: reclining seat back, wheel locking mechanism, and hand-powered propulsion.

The main frame of the device is constructed from wood to keep it feasible and sustainable for people to construct it in Kenya. The frame of the device consists of two U-shaped wooden frames attached together with a second plank of wood to provide more strength and support to the joints.

The seatback reclines using two door hinges that attach to the main frame. A T-bar, attached to the rear main frame using a small hinge, supports the seat back at a 100° upright position, or can be disengaged to change to a 180° reclining position. Two L-brackets attached to the seatback provide a “stopper” to secure the T-bar in place in the upright position. Velcro straps prevent the T-bar from moving out of the L-brackets on rough terrain.

The wheel-locking mechanism keeps the device stationary while the user enters and exits the device. Two door latches attached to the bottom of the device are released into the wheel spokes to lock the wheels in position.

The child propels the device by manually spinning two 12’’ pneumatic bicycle wheels.  A common axle, connected to the bottom frame via one L-bracket on each side, provides stability for the cantilevered wheels. Three caster wheels, two in the front and one in the rear, provide stability and make the device easy to turn.

Leg guards attached to the front frame keep the clients’ legs from sliding off the device, and an adjustable seat belt keeps the user securely fastened. Removable, Velcro-secured Cushions add comfort and prevent pressure sores on the clients’ back and legs. Finally, spoke guards on both sides of each wheel protect the client from possible finger injuries that could arise from spinning spokes.   Cost of parts for the device was about $290.

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