This project would require the freshmen to design their own crane under the following guide lines: The crane itself has to be mobile, however, the form of mobility is up to them. They could use tires, (let them choose how many and what size,) some sort of rotating belt, or anything else they think would work well for this type of machine.
The crane should be able to pick up objects of various sizes and stack them. This could be made into a competition. The freshman would have to drive their cranes over a bumpy terrain (made up of lego pieces) to pick up an object, and then drive the object back and place it on a pile of previously picked up objects. There would be a list of objects that the crane would try to pick up and then place on top of the growing pile. The objective is to figure out what order to pick the objects up in so that they are easy to stack, and then to stack them as quickly as possible. The crane that could drive and pick up the objects the fastest while still maintaining control when placing the object on the pile would win. This project would require the freshman to build their machines for speed and dexterity,( and it would be a lot of fun.)
The freshmen would build their own cement mixer for this project. The barrel on this machine would have to rotate as well as move in the vertical direction to enable the pouring out of cement. This machine would also have to be built for ruff terrain so that it could travel off road to work sights. The cement would be tested at interval for water content and thickening. If more water needs to be added, the machine would sense this and add water. The water could be added by using a small tubing system with a pump. The water would be pumped out of a small reservoir into the tubing and then controlled by a valve. This valve would operated through a switch that received computer commands to activate or inactivate the valve. The freshman would learn about the mechanics of a machine as well as some material properties of cement.
A transmission could be built that would be able to switch gear. This would be done manually. A set of buttons would be wired to control different gears. If a new button was pushed the transmission would switch to that gear. When changing the speed of the motor, the user would have to switch gears accordingly. This project would teach the freshmen how a transmission worked from a mechanical point of view as well as from an operational point of view.
The object of this project would be to design a drawbridge that uses some sort of sensor. When the sensor is activated the bridge will open. A possible sensor could be a light sensor. An on coming object would shine a light at the sensor conveniently located on the bridge. This sensor would then send a command back to the control board to activate the raising of the bridge. The requirements for the bridge itself would be that its deck has to be mobile. However, the actual design of the deck would be left up to the students. One possibility is that the deck could be split into two halves, and each side could raise half of the deck. Another possibility is that the deck could be a solid plank that is attached only on one side to the supporting foundation of the bridge. The other side would be free to move up or down in order to raise or lower the bridge.
The students would also have to decide what type of bridge then wanted to build and would have to design the mechanism to move the deck. They would be given a set of pictures of various types of bridges with a description attached. The descriptions would discuss what type of bridge it was and the physical aspect behind the design. They would choose which type of bridge they wanted to build based on the information they were given. In this way they would learn a little bit about bridge design while they were learning about building a mechanical system.
This idea is my personal favorite, but I may be partial to the subject.