25-26 Week of 5/25-5/29

With about a month left of school, our students are pushing to finish projects. There is always work to be done, so we’ll keep working until the last day of school. Here are a few highlights from last week.

Junior Alex Bress ’27 was working on a 3D printed case for his project:

This week was shorted oddly, since we only had the last half of the day on Tuesday and Wednesday due to MCAS testing. I worked on the piano case and the other physical components of the piano. I also did a fair amount of research to find the best design, setting me up well to finish the project.

On Monday, I finalized the new idea for the speaker box, a wedge with the PCB on the top as a lid. This is best for a number of reasons. Firstly, the more simple design makes it easier to reduce vibrations and extra parts. The bare PCB also makes it far easier to mount the pressure sensitive resistors, with the flat pins and short leads. The wedge shape is also best for sound quality, since it keeps the sound waves from reflecting directly off the back of the speaker and canceling out new waves, particularly on the mids and bass. However, since the bare PCB is exposed, I will need to use a metal core board, most likely aluminum instead of the standard fiberglass for strength.

On Tuesday and Wednesday, I worked on the CAD model for the case and printed it out on the three dimensional printer. However, the bed lifted and the walls are slightly to thin, so I could not use it for the final product. The components also had arrived by now, so I was able to test fit all of them, especially the new rocker switch, since they are press fit. While I was waiting for everything to print, I also tested the new electronics components on a breadboard, which worked beautifully, albeit quite loud, so I will add a potentiometer as volume control.

On Thursday, I did more research on the PCB and finished the PCB design in Fusion 360. I will probably need to send the design to a manufacturer instead of the PCB mills we have in shop, since we don’t have all the materials and the board would be too large to cut out on ours. I also printed out the final case design after making some slight adjustments to the measurements. Hopefully I will be able to use this as the final case, since wood is far more difficult to work with. Next week, I hope to finish the project as best as possible and maybe get started on OSHA certifications.

p.s._{^{There are supposed to be images of the 3D print, CAD file, components, and PCB design, but they are having difficulty uploading them, so I don’t know if they will be visible.}}

See more of Alex’s work here.

Sophomore Ibrahim Ahmad ’28 is taking the Sumobot competition quite seriously. Here is is heavily redacted blog post keeping his design ideas top secret:

Prototype Build Progress

I printed the tray and mounted the motors and redactxx onto it. This gives us our first full rolling prototype layout and confirms that the core mechanical fit is working.

My partner has also been working on the code, and we have the motors running at redactxredactxredactxredactxredactxredact. We also sorted out the redact and laser-cut the prototype wheels, so the drivetrain pieces are now coming together.

Code Update

For motor control, our current forward(int wait) routine sets direction with digitalWrite(█, HIGH) and digitalWrite(██, HIGH), then applies PWM using analogWrite(█, ███) and analogWrite(██, ███), followed by delay(wait).

void forward(int wait) {
    digitalWrite(X, HIGH);
    digitalWrite(XX, HIGH);
    analogWrite(X, XXX);
    analogWrite(XX, XXX);
    delay(wait);
}

We are using analogWrite() on an █-bit PWM scale (█ to ███), so a value of ███ corresponds to about ██% duty cycle. redactxredactxredactxredactxredactxredactxredactxredactxredact.

redactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactx

void irFlashTest() {
  redactxredactxredactxredactx;
  redactxredactxredactxredactxredactx;
  redactxredactxredactxredactxredactxredactx;
  redactxredactxredactx;
}

Left wheel

Wired Motor Module

Bearing and mount detail

Weight Budget Check

I have started a running tally of the robot’s weight:

• Tray + mounted components: redac
• Battery: reda

That puts the current subtotal at redac.

If the competition limit is redac, that leaves redac redactxredactxredactxred and PCB combined. Since PCB weight can still change, I will make a rough estimate using my lightbox PCB and then use the remaining allowance for the redactxreda

redactxredactxr redactxredactxredactxredactxredactxredactxredactxredactxredactxred

Next Steps

Next, I will lock in a PCB weight estimate, finalize the redactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactxredactx

See more of Ibrahim’s work here.

Our Freshmen were finishing up the Thread Gauge Project, and will move on to the 3D Printed Steam Engine next time they work on CAD. It’s back to circuity and coding this week.

All for now.