semi automatic pneumatic door control system for bus havin Zig Zag door woth just of Rs.1000/-

By use of pneumatic cylinder we can make semi automatic door system for zig zag door in bus .. it is my mini project and it is implemented in one of the bus in KNOWLEDGE INSTITUTE OF TECHNOLOGY .. the project was awarded by college resource persons .. to make the project with this cost is the trick which i am having myself as secret .. here it is controlled by 5/3 lever mechanism ..