A smart wheelchair for all occasions

Mr Mbiria is back in Kenya to perfect his project. If he wins, the immediate reward will be £25,000 (Sh3 million) and perhaps a chance to spread his innovation beyond Kenya.

When Peter Mbiria’s friend lost her ability to walk four years ago he was pained watching her struggle to do the simplest of tasks despite having a wheelchair.

He was only 17 and had just completed high school but he thought it was time the wheelchair was reinvented — and he took up the challenge.

Last week, he was selected among 16 finalists who were in the UK for the Africa Prize for Engineering Innovation by the Royal Academy of Engineering in London for his smart wheelchair — E-Con.

“Inventors of an all-terrain ‘smart’ wheelchair, a solar-water heating appliance that slashes energy use by 90 per cent and a pneumonia-diagnosing biomedical jacket are among African innovators recognised by the academy as the continent’s future technology pioneers,” said the competition’s website.

But for the former engineering student of the Technical University of Kenya, who is waiting to graduate, the main concern is how to mass produce E-Con to benefit those like his friend Florence whose needs cannot be served by basic wheelchairs.

“I saw her struggle to do things like washing dishes as she could not reach the level of the sink from her wheelchair and I thought I had to do something,” he says.

COMFORTABLE TOO

This inspired the idea of a wheelchair that could enable her to not only be mobile and independent but also comfortable.

His prototype wheelchair is all-terrain and allows users to stand upright, climb stairs and generally self-navigate.

It can also ascend or descend a flight of stairs and “walk” over obstacles while keeping the user level at all times. No wonder it was well-received in London.

Using two pairs of tri wheels, it can also go over bumps, curbs and obstacles that would normally require considerable upper body strength but, usually, a push by an assistant or a ramp.

“It has a Gyro sensor at the centre of the chassis that records any time the Y axis of the wheelchair tilts. These values are transferred in split seconds to a microcontroller that computes them accordingly using a loaded programme and gives them as output to the Servo,” he says.

He adds: “The Servo in turn tilts the chair minus the number of degrees recorded by the Gyro Sensor. For instance, if the Gyro sensor records a tilt of 10 degrees, the Servo will tilt the chair minus 10 degrees. This way, the user will be at level and won’t even feel the movement.”

Gyro sensors, also known as angular rate sensors or angular velocity sensors, note the change in rotational angle per unit of time.

CORRECT PERFORMANCE

A servo is an automatic device that uses error-sensing negative feedback to correct the performance of a mechanism.

Additionally, the E-Con wheelchair has two different sets of gears attached to the chassis that can tilt independently along the width, enabling the user to remain upright even when a set of wheels is lower than the rest, like when in a trench.

During this time, all the sets of tri-wheels will continue rotating, enabling the wheelchair to navigate the trench with ease.

“If the wheel at the lowest position of the tri-wheel set gets in a trench, the wheel next to it will by default touch the ground and take over, ensuring the wheelchair keeps moving without requiring human assistance,” says Mr Mbiria.

He adds: “By having two separate sets of independently moving differential gears that can be controlled by a switch, the user is guaranteed of remaining upright if for any reason there is a tilt of up to 45 degrees.”

Designed using aluminium fibre, the wheelchair is powered by a rechargeable Lithium ion battery that can enable it to run for a full day on a flat surface and half a day in strenuous conditions.

Its chair can also tilt upwards or downwards at the touch of a button, enabling the user to reach distant objects.

‘TO EXERCISE’

“Sitting down the whole day can be boring at times. I thought that by making the chair movable, the person using it would also get a chance to exercise,” he says.

Its inventor believes that if produced on a large scale, it would contribute to growth of Kenya’s economy, besides solving most of the problems faced by the physically challenged.

According to census statistics of 2009, 1.3 million — or 3.5 per cent of Kenya’s total population — are people living with disabilities. Of this figure, 31 per cent are people with physical disabilities.

“If a significant percentage of the population is unable to move with ease or do basic tasks, their contribution to the economy is minimal. Worse still, other people have to assist them, which is time that could have been spent building the economy,” he says.

He says his biggest challenge in creating the wheelchair — like many techpreneurs in Kenya — has been lack of finances and proper structures by the government to transform innovations into reality. In 2014, he invented an unmanned surveillance robot called Linda Nchi that was widely covered in the media but is gathering dust at his home.

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