Qatari inventors won four medals, including a gold and two silver, at the 44th International Exhibition of Inventions in Geneva, Switzerland. The wining inventions by the members of Qatar Scientific club included a palm size cheque printer that works with rechargeable battery, a bullet-proof material made of local components, a smart surveillance system that employs a robot to detect suspicious movements, and a computer programme that deploys sensors for the traffic lights to ease congestion on roads.