Status Report for October 13, 1995
Team 7
David Greene
Patrick Sullivan
Tia Likely
Advisor: Dr. Peter M. Kogge
10/8/95 - Tested the moving pivot design by connecting the motors to the computer. The initial test failed, and the gearing on the pivot motor was improved.
10/9/95 - 10/11/95 - The design of the hanging spring balance was attempted. Several designs for the frame to hold the mass and the mechanism to move the light sensor vertically were built. None of them worked very well.
10/12/95 (Projected) - The prototype of the software to control the moving pivot balance will be written, and measurements will be made to determine the various constants needed (reference masses, pivot move distance vs. motor rotations, etc.).
This week we fell a bit behind schedule. However, during the fall break, we plan to write a good portion of our draft documentation, which should help alleviate the crunch during the following week.
Improving the gearing on the moving pivot mechanism proved to be very interesting. It was difficult to devise a system so that the pivot would move smoothly across the track. However, the final design works very well and is extremely stable. In fact, by manually controlling the pivot from the computer, we were able to balance the see-saw when there was a mass in one of the pans.
The improved gearing system also has the side benefit of increasing the number of motor revolutions required to move the pivot from one end of the balance to the other. This will allow for a more accurate measurement of masses.
The main problem with the hanging spring balance is that suitable springs are very difficult to find. We obtained about 5 or 6 more springs during this past week, and most of them are too stiff. The springs that seems to have the right tension are not long enough, and will not provide enough of a change in length to allow measurement of several different masses. Dr. Kogge brought up the idea of using a rubber band in place of a spring, and this idea will be explored.