3/22 to 3/29

It was spring break, all team members were out of town during the break. However, the sensor bracket for the Hall Effect sensors and the magnets were redesigned before the break. The drawing was sent to the 3D printing shop, and the 3D print was in process. The sensor should be ready at the end of the break, and the team will start wiring up the encoder after the break.

Week 3/15 to 3/22

This week, the team spend time on manufacturing the corrugated metal strip for the whole track. The team first cut out metal strips with the sheet metal shear in the shop, then use our device to create the corrugated metal strips. Because of random error made by human during cutting out the metal strips, the width of the metal strip cannot be exactly 5 mm as designed. Our team tried to control the cutting process in order to keep the width of the metal strip to be 5.5 ± 0.5 mm. A few strips was measured to be out of the tolerance level because of the improper manufacture process, and we replaced them with new strips. The strips were successfully cut and corrugated, the team is waiting for the completion of the track.

03/09/2017-03/15/2017

In this week, our team was focusing on programming the position sensing system. The idea was to create a function which counts for once when one of the sensors detects a signal change from HIGH to LOW, calculates the corresponding distance from the counts, and display the distance of the podcar from the last station. The program was finished, but the team is facing a problem of experiencing a high-frequency signal change of the sensors if the podcar stops at a position where the sensor detects a portion of the peak. The team is planning on adding a LOW PASS DIGITAL FILTER to our program. Hopefully, the problem can be solve with the low pass digital filter.However, we are trying to get advice from the app development team first.

Attached is the presentation 1 from our team:https://drive.google.com/open?id=0B2G9D1-TIftEQkZlRDJIRUliMWc

03/02/2017-03/08/2017

In this week, our team mainly focused on the presentation. In order to display the precision of our sensing system design, we made speed testing device. This device was made by a circular wood board, a corrugated metal strip, and a Hall Effect sensor. We fixed the strip on the edge of the wood board, and also we fixed the Hall Effect sensor on another wood board. The distance between sensor and the strip would be about 3mm. The outlook will be shown below(Figure 2).

In addition, we also did some improvement for the device which used for making the corrugated metal strip. The outlook will be shown below also(Figure 1).

Figure 1:                                                                       Figure 2:

02/23/2017-03/01/2017

In this week, our team already found the acceptable sheet metal. The gage of the sheet metal is 30 which was what we expected. We decided to use this sheet metal for our corrugated metal strip. We cut a small piece from the sheet metal for testing. The result was promised. Therefore, we decided to use it for our project. Our next goal is cut the piece out from the sheet metal. The width of the piece will be 5mm.

In addition, we refined the gear set platform. We added a base for the platform in order to level it. We found the gears would be pushed apart when bending the metal strip. Thus, we add a piece of wood to connect the top of the two screws. The added wood piece would keep the gears together. The refined gear set works perfectly with our new sheet metal. Our team is ready for corrugated metal strip fabrication.

2/15/2017 to 2/22/2017

After failing several times with wood, the team decided to move on to the backup plan which is 3D printing out the gears. This week, the gears are printed out with ABS. The team assembled the gear together on the wood board, and test the gear set with a sample ironic strip, and the strip was successful corrugated. With the gears successfully made, the team will be able to make corrugated metal strips in large volume.

02/09/2017-02/16/2017

In this week, our team tried to use the wood board to create two set of gears which used for manufacturing the corrugated metal strip by hand. Unfortunately, we failed. At the beginning, we used a wood board which thickness is 1cm. After we cut out all the teeth of the wood gear, we realized the teeth are very brittle. When two gears rotated for making the strip, one of the teeth broke. Therefore, we decided to use a thicker wood board which is 2cm to do it again.

Manufacturing the thicker one is a lot harder than the old one. Especially, when we tried to make the teeth, we had met a lot of trouble. Firstly, we could not make the same distance between each tooth by hand. It will cause the unequal distance between the peaks of the corrugated metal strip. Secondly, at the tip of the teeth, we needed to sand it a little bit. It can make the rotation smooth. When we sanded it, we needed to be really careful. It is because the width of each teeth required minimum 3mm. Under that much limitation conditions, we realized we failed again. Fortunately, we had a backup plan which is 3D print. We asked help from our friend who has a 3D printer. Also, we start to draw it out by Solidworks. The gear set could be done by next week.