We endured some pretty cold temperatures last week, but even the frigid weather could not stop our students from putting their heads down and getting to work. A lot of great stuff happening in the shop this week!
Junior Jaspreet Kaur was working on updated code for the large Word Clock.
This week I resumed work on the Word Clock code. When I revisited this project I found that there were multiple issues with the code. The first issue I found was that the clock would not display the correct time. When I would run the code, the Real Time Clock (RTC) got the wrong time and would display a completely different date and time from the actual time. My first solution to this issue was to switch the RTC with a new one that was actually working because I assumed that the one I had been using broke. This worked for some time until the serial monitor displayed that it could not find the RTC at all. After looking at the Adafruit guide I found that the issue was with the RTC piece because there was no battery pack in it. The RTC required a CR1220 battery which I had not used. After I put the battery in, the RTC worked flawlessly.
The next issue I found in the code was that it could not read the time that was displayed in a 24-hour format. This problem would cause it to stop displaying the hours on the light strip. I believe there is a method to change the format of the RTC to be in a 12-hour format but I was unable to figure that out. Instead, I decided to add a part in the code that would subtract 12 from whatever hour was displayed on the serial monitor or accessed by the RTC. I found this change in the code to be incredibly useful and it solved the problem that I had with the display of the lights after 12 hours.
The final part of the code that I needed to fix was an issue with the minutes. When the RTC reads the time at a full hour (3:00 for example) it does not display the hour as it should. The light strip should display “it is [hour] o’clock,” but right now it does not do that. As of right now it omits the hour entirely so most of the strip is completely dark except for the “It is” and the “o’clock.” In order to fix this I added another part to the code that accounts specifically for when the time falls between zero and five minutes. This code I added hasn’t worked yet so I am still trying to figure out the solution to this issue.
This project is really beginning to come together. Check out more on Jaspreet’s website, linked here.
Senior Tanzerul Azam continued work on two projects.
This week was a very turbulent week in terms of progress on the shopping cart. Starting off with Tuesday, because we had Monday off due to MLK day, I began by reprinting and changing the measurements on the coupler again. The coupler has gone through several iterations at this point so it made it all the more fulfilling once I had gotten it perfectly done. I’d done 6 different prints taking around 2 weeks to get through all those prints due to the extended process of resin printing. There were three main areas of issue with the couple design which was the hole where the coupler goes on the motor shaft, the hole where the couple goes on a protruded part of the micrometer, and then there are two holes on the sides of the coupler for bolts to go through which allow for the tightness of the coupler to be adjusted. Usually the problems with the coupler would be that it would not fit on the micrometer or the motor hole would be too loose or even the the space for the nut would be too large but I finally perfected the sizing on the entire coupler. However the stage has two different micrometers meaning two couplers are required.
I still have yet to print the other coupler because I ran into some issues with the resin printer while printing today. It had an error where the mixing bar got detached and was never resolved so I didn’t get to actually print the coupler. Other than the the coupler I was also working with my steel finally. Last week I managed to get three out of four of the holes drilled into my steel. The holes are not perfectly centered on the steel bars which at first looks like a mistake but it had to be like that because the holes I had originally drilled in the shopping cart frame were not perfectly in line with each other. Drilling each of the holes on the drill press took a little bit of time with each hole because it is eighth inch steel which generates a lot of heat so I had to peck and take my time with the holes I drilled. Before I got to drilling the hole however I spent some time on fusion relearning a couple very useful tools it offers. There was a glaring issue with the design of the shopping cart engine and axle mount which is that fact that it is not very structurally sound. I’d learned how to use the stress simulation software in fusion and ran a couple tests and saw that the current design I had would see a whole lot of permanent deformation and potentially snapping so I had to come up with a solution.
I spent a day reteaching myself how to use the sheet metal tab in fusion to make these bars which would connect to the square steel tubing and the frame of the shopping cart and act as compression bars stopping the tubes from bending upward. However after modeling all that I ran the simulation and saw that it literally did not change a thing and the entire idea was scrapped. I deleted the entire thing so I have no pictures of it. Next week I have to think up another idea for the frame to make sure it doesn’t break under the force which I calculated to be 880 Newtons of force but that’s also a very rough estimate and nowhere near exact.
See more about his projects on his website, linked here.
MVTHS Engineering 
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