The design team agreed on a few changes early this week. I updated the pencil drawing to include those changes and to correct a mistake. I drew the tubes with a 4″ diameter by mistake. This is one of the many instances in which I remind myself of the wisdom of Bob Villa. He taught me to always “measure twice, cut once.” This is why we must always check and discuss our plans before building, especially when the acrylic tubing costs $30 per foot.
We cut the sheets of acrylic on a regular bandsaw. The adjustable fence on both saws allowed us to set a length and cut them all precisely.
Russ worked with the drill-press to put holes in the sheets of acrylic. We were able to do the basic tasks, but the more elaborate work needed a machinist. We were working in the shop of Alessandro Betti. He showed us how to use the saws and the drill press. He helped us tweak the design and machined the more tricky aspects of fabrication. This is an image of him cutting the groove for a gasket.
It was water tight. Our next test will be to verify the accuracy of the Ping ultrasonic sensor. The sensor will measure the distance to the water’s surface. The basic stamp will be able to calculate the time it takes for a predetermined volume change. This will give us our flow rate through the soil. The Ping sensor will sit at the top of the tube.
I must call it a night. Next week I will feature our soil research. We have been conducting soil permerabilty tests and sieve analysis on soil. The sieves are not able to separate clay and silt from each other. We are hoping to do a soil hydrometer test to quantify the silt and clay. We are shaking the sieves to sort the soil by particle size.
This work is supported in part by the National Science Foundation under a Research Experience for Teachers (RET) Site grant EEC-0807286. We thank the Mechatronics Lab and the Soil Mechanics Lab for hosting us during our summer research program.