On a freezing winter night in Glasgow, most people passing through the city streets were probably thinking about getting home, turning on the heating, and escaping the cold.
Rebecca Young noticed something else.
She saw people who did not have a warm home to return to.
People were sleeping rough on the streets, exposed to Scotland's bitter winter weather. For Rebecca, who was still a schoolgirl, it was difficult simply to walk past and forget what she had seen.
She began thinking about a question that was both simple and surprisingly ambitious:
What could she actually do to help?
Rebecca was only around 11 when she began developing an answer.
She did not have a factory. She did not run a technology company. She did not have years of engineering experience.
What she did have was an idea.
And eventually, that idea would travel from a schoolgirl's drawing to an engineering workshop — and then into the hands of organizations helping people experiencing homelessness.
Turning Concern Into an Engineering Idea
Rebecca was a pupil at Kelvinside Academy in Glasgow when she took part in Primary Engineer's "If you were an engineer, what would you do?" competition.
The programme challenges young people across the United Kingdom to identify real-world problems and imagine engineering solutions to them.
Rebecca chose a problem she had seen with her own eyes.
People sleeping outdoors needed protection from the cold, but a conventional electric blanket would not be much use to someone without reliable access to a power outlet.
So Rebecca began researching.
She looked at sleeping bags and backpacks and thought about how something warm could also be portable. People experiencing homelessness often have to carry their possessions with them, meaning any practical design would need to be light enough to transport and useful without being connected continuously to mains electricity.
Her solution combined several familiar technologies in a new way.
She envisioned a heated blanket integrated into a backpack and powered using solar energy.
During daylight hours, solar panels could generate electricity that would be stored in a battery. Later, when temperatures dropped, that stored energy could power the heated blanket.
And when the blanket was no longer being used, it could be packed away as part of a backpack.
It was a concept designed around the circumstances of the people Rebecca hoped it could help: portable, rechargeable and able to provide warmth without depending on a nearby electrical socket.
What began as a child's competition entry was remarkably practical.
And engineers noticed.
One Idea Among Tens of Thousands
Rebecca's proposal entered a competition involving an enormous number of young people.
Primary Engineer said her design emerged from a programme receiving more than 70,000 entries.
Among all those drawings, inventions and proposed solutions, Rebecca's solar-powered heated blanket stood out.
But the most extraordinary part of the story was still ahead.
Primary Engineer works with engineering and university partners to select some children's designs and transform them into functioning prototypes.
Rebecca's drawing was selected.
That meant professional engineers were going to try to build what she had imagined.
The task was taken on by a team at Thales in Glasgow.
Instead of treating Rebecca's entry as simply an inspirational drawing from a child, the engineers approached it as an actual engineering challenge.
Could the concept work?
Could the blanket remain portable?
Could solar power charge a battery effectively enough for the intended purpose?
How should the heating system be controlled?
How could the design prioritize user safety?
Those questions moved Rebecca's idea from imagination into engineering.
From a Drawing to a Prototype
A team of graduates and apprentices at Thales began developing the prototype.
According to Primary Engineer, the design evolved into a heated sleeping-bag-style system that could retain warmth while remaining portable.
Engineers worked on the individual components, testing the battery, heating elements, control circuitry and solar-charging system.
They also used computer-aided design and 3D printing to produce parts for the backpack structure.
The solar panels needed to be positioned so they could charge while the backpack was being carried. At the same time, the backpack still needed to provide useful storage.
The engineering team therefore developed an outer frame capable of holding the solar panels while preserving space inside the bag.
Another important challenge was controlling the heat.
A heated product designed for vulnerable people could not simply become hotter and hotter without regulation. The prototype therefore incorporated controls designed to manage temperature and energy consumption.
Primary Engineer reported that safety was a central consideration during development and that the design included multiple heat settings.