In general, systems consist of sub-systems that relate to each other by inputs and outputs. Energy conversion requires rather complex systems, and conversion efficiency depends on how well the sub-systems are connected, and how well the input/output relationships are optimized with respect to the overall system efficiency. Furthermore, ensuring proper operation of complex systems requires computer control and interfacing between our thinking and physical realization. Throughout the course, you will be programming circuits and machines; good programming habits involve flow diagrams and documentation of the ideas and code. Task1 is a hands-on abstraction of these concepts.

I. Objectives

Deposit sand in specified locations
Use only the provided materials and tools
Utilize a minimum number of steps / energy transfers
Present the design and final mechanism
Teams judged on Efficiency, Durability, Economy, Spectacle / Delight of mechanism

II. Deposit locations

A given mass of sand starts out at a position 100 centimeters above the table; specified in Cartesian coordinates by (x0, y0, z0) = (0, 0, 100 cm). A fraction of this sand must be deposited in paper cups positioned at 3 locations given by:

Location	Minimum Mass	Cut-off Time
(x0, y0, z0) = (0, 0, 100) cm	100% of original mass	0 minutes (from start)
(x1, y1, z1) = (0, 0, 100) cm	50% of original mass	5 minutes (from start)
(x2, y2, z2) = (0, 60, 80) cm	50% of mass at (x1, y1, z1)	10 minutes (from start)
(x3, y3, z3) = (40, 40, 60) cm	50% of mass at (x2, y2, z2)	15 minutes (from start)
(xm, ym, zm) = (150,150,150) cm	Maximum volume allowed for your system

III. Materials, Tools

Cardboard, String, Duct Tape, Box Cutter, Dowel Rod, Wire, Paper Clips, Binder Clips, Rubber Bands, Sand

IV. Judging criteria

Efficiency: Delivering a greater fraction of the original mass of sand (from Location 0) to the Location 3 is better than delivering a smaller fraction. Delivering a larger total quantity of sand may or may not be better (feel free to explore this as a design parameter). Delivering equal amounts of sand to all 3 locations might be desirable. (But why?..)


Durability: The mechanism you devise must survive the endeavor and must be capable of a repeat performance. The greater the durability, the better. (Or is it?..)


Economy: The fewer materials / tools you use to construct the mechanism, the better. Unless you can use more materials, but the overall cost is lower. The exception is when the mechanism could be made much more engaging by using more material. (Unless you think that isn’t as important as when increased capital cost leads to improved efficiency and/or durability...)


Spectacle / Delight: Designing and building a more dramatic delivery mechanism is preferred, but not to the detriment of durability. (Unless your whole point was to have an ephemeral / biodegradable mechanism in the first place, or you just wanted to make a “splash” with it. Of course, you might also want to make the least obtrusive mechanism. Or, maybe if you are able to achieve your objectives with minimum amount of material, shortest delivery time, and lowest capital costs, then perhaps the level of “noise” or spectacle doesn’t matter at all...)


More images here and here.