Week Eight B

Last Thursday, we took our perch to the pool! At the pool, we made sure everything worked under the water. The propellers spun properly, propelling the submersible through the water. The submersible had a little trouble fighting the waves produced by the lap swimmers. Because we plan on using the submersible to collect water samples from the river, waves shouldn't be a problem. If the submersible were to be used in a body of water with strong waves and/or currents, larger propeller and perhaps a stronger motor may have to be used.

While at the pool, we figured out how much of the Styrofoam noodle we needed to balance our SeaPerch. We cut the foam down until the ratio of floatation resulted in the SeaPerch being sufficiently buoyant. We also utilized the depth sensor. While in the 4.5 foot zone the depth sensor read 3.4 feet. This makes sense because the frame of the perch and the distance the sensor hung down was about this difference.

The SeaPerch successfully took two samples of water. After taking the first sample of water, the mechanism was reset and tried again. The video below is from the second trial. Several problems were noted during testing. First of all, the wires often got in the way of the propellers. This problem was fixed temporarily with zip ties. The SeaPerch was slightly unstable and the hot glue did not hold up. The PVC pieces came apart and had to be pushed back together. The floatation rings slid around and fell off if the PVC pipes separated. The motor that pulled the syringe plunger was slightly wobbly and needed to be better secured. These problems will be addressed.

Below are a few pictures and a video from testing. For more pictures, see the page to the right titled "Pool Testing Photo Album".

Chris, Ben, and Andy man the switches, battery, and depth sensors

Rod swims with the SeaPerch

The water sampling device

                                            

The depth sensor at work

Underwater video of the submersible taking a water sample!