 There are a lot of innovators making a difference across Africa. And this week on People Fixing the World from the BBC World Service, we're going to Kenya to meet some of them at a special event. The Africa Prize for Engineering Innovation rewards the best problem solvers from across the continent. Today we meet the finalists, including someone who's come up with a pest detector for crops. For us, when we see increased yields, when we see reduced crop losses, when we see improved livelihoods,