This week, I made a major software breakthrough on the ROV. The IMU will periodically return invalid data, likely due to a faulty sensor. Due to the lack of error handling in the code, the ROV would receive a null value and the enire software system responsible for the control of the ROV would crash and need to be restarted. This bug that I’ve been tracking for nearly a month now was resolved by simply implenting some basic catches to detect when these null bits come in, and simply ignore them.

This week, Tim finished his electronics skeleton that he has been working on for the past few weeks. It looks very nice and is completely custom designed, machined, and resin printed. I helped him install it into the ROV, and I can already tell that it will make things significantly easier in terms of debugging and also performance of the overall machine. The previous layout consisted of floppy acrylic fingers that held the PCBs in place.

The first 2 days of shop this week were spent replacing XT30 connectors on the ROV’s power distribution board. There have been connection issues in the past, and I really didn’t want this to factor into existing reliability issues. On Wednesday, Jonas Wirz and I got the ROV into the pool, however, we had some free time before then and were very productive with it. Short-lived gated off area exploration (right).

This week I locked in and spent a good chunk of time identifying the reasoning behind the mysterious crashing phenomenon we have been experiencing for over a year and a half in the ROV. Raspberry Pi 5 Problems In the past, the main control computer (RPi 5) was experiencing power interruption issues due to the massive current draw of the 8 thrusters. Because of the low dropout voltage in the 5 volt regulator, we found that adding some capacitange along these output lines helped smooth out any wild ripples.

This week was a bit funky. Not only did I have limited time in shop, but limited time in school overall! Our school had a half-day on Wednesday (we get released at noon) and the day after was a snow day. Because of these two things, I didn’t have a whole lot of time to work on roboticy things. This is enough to call a snow day?! Nonetheless, my friends and I ended up getting some work done on the ROV on the days we did have.

This week consisted of a combination of activities both during shop-time and during robotics club. I spent the majority of my shop time helping my classmates with their light boxes. This included anything from crimping connectors to soldering small parts onto PCBs. I also spent some time optimizing the ROV in terms of performance and reliability, which included setting up a systemd service to automatically start the main ROV software.

This week, I worked on the ROV for the robotics team as I had already completed the lightbox project as shown in the previous post. The robot has been experiencing some reliability issues, and they have something to do with the Raspberry Pi 5 we have onboard. The Pi would suddenly “crash” (meaning a loss of connection over ssh; ethernet port lights turned off; only red power light was illuminated) without warning.

The lightbox has been finished! I designed the acrylic and manufactured it on our laser engraver/cutter. The end result was better than expected, although I had to condense (shorten) the acrylic overall to meet the max acrylic dimensions of 70 square cm. After the transparent acrylic was finished, I screwed it into the lightbox and “force fit” everything together as designed. Luckily my tolerances and dimensions matched perfectly. The acrylic had to be custom designed to fit the screw holes and the box geometry.

While in robotics this week, I continued my work on the lightbox project. This week involved a lot of CAD and 3D printing for me, and ended up taking a bit more time than expected. Generally speaking, I am ahead of schedule so I don’t have to worry too much. The light box is composed of two main parts that get 3D printed and screwed together. There is the base which is the outer shell and holds the button and power jack.

During my time in the Robotics Shop 5th and 6th period this week, I made significant headway on the lightbox project. For my lightbox, I will be making a transparent “EXIT” sign that you frequently see in modern office buildings. These signs are very expensive and can be found online for hundreds of dollars. My plan is to make it for much less. The most expensive component to the project would be the acrylic, which can be found for about 10 dollars for an appropriate size.