1/20/2026 9 AM - Created schematic and placed components

Today, I saw this video, which seemed pretty cool. I decided that I wanted to make my own, but add some upgrades to it. I wanted it to run on a custom ESP-32 PCB, have built-in speakers, and LED visualizers. I began with the schematic, for which I copied over my ESP-32 base files:

This is how I start all my ESP-32 schematics. I then added another 2 USB-C connectors for power output:

The 5.1k pull up resistors tell the USB that it is set to power output. I then added connectors for LEDs, a gesture sensor, and an RFID reader. I just used a generic pin header symbol and 2.54 mm footprint for these, as I can solder wires into them easily:

And then I created a Neopixel array for my visualizer. I decided to have an 8x3 array:

Then, I added a stepper motor driver. There was some discrepancy online of the pinout of the motor, so I might have to rewire the motor when I begin testing. I used a reddit post and the datasheet to come up with this:

Finally, I used a MAX98357A and its datasheet for audio output. I decided to go with a left+right channel average for the gain:

Then, I imported the parts into the PCB editor and began laying them out. This time, I decided to go with a cut PCB for the esp32 antenna, as I thought it would look nice. I followed the layout guidelines for this and ended up with this shape:

I then placed the rest of the components, trying to keep eveything neat and in order. This is my placement that I came up with:

I also began routing, but I think I will redo it next time, as I don't like how it is currently.

1/20/2026 7 PM - Routed the PCB

Today, I had no homework, so I sat down and decided to route the PCB. There is not much else to say. I did add in a hall effect sensor and a power switch, two important things I forgot earlier. They look like this:

I added those in to the PCB and routed it. I kept with routing the B.Cu traces horizontally and the F.Cu traces vertically, which helps a lot. I also placed and routed the neopixel array. I connected the two using mousebites. There is not much else to say, as I just connected the parts. This is what I have now:

1/22/2026 - Finished CAD

Today, I had no homework, so I decided to stay up until 1 am working on this project, along with other tasks. I finished the PCB, so I began the CAD. I started by creating an outline square that would serve as my boundary while I placed my parts. I imported all the required parts, settling on an 8 ohm 10 watt speaker, and placed them in the box. I did have to change the dimensions a few times, especially when fitting the speaker, and this is what I came up with:

Then, I extruded the bottom and began creating the bottom half. I extruded it up to the top of the stepper motor, minus about 3 mm to let the top stick out. Then, I began creating holders for each of the parts. I projected their screw holes onto a sketch and added a circle with a diameter a few mm larger. Then, I extruded these circles and added threads to them to allow screwing. This is what it looks like:

I then projected the neopixel shapes onto a sketch and extruded that into the case to allow the light to shine through and show in grids. This is what I have:

After that, I once again used the projection tool to create USB holes, which I extruded and chamfered using a value from past designs that has worked for my cables:

I also added the following design on the front and sides of the case to give it some character using the rectangular pattern tool:

After that, I created the top. This was simple enough, as it was just an extrusion off the current bottom, and I closed off the top. I then projected the circles of the speakers to cut out holes using the pattern tool, which looks like this:

After that, I added a hole for the stepper to stick through, added a turntable, and a hand that has a magnet embedded in it to allow for the hall effect sensor to work:

I added a sample disk, and now my project is mostly complete!

1/23/2026 - Finalized PCB and CAD

Today, I added an SD Card reader to the PCB to allow me to have offline music. This way, if I'm not connected to Spotify, I can still play some music or play a "You are not connnected" tone (or elevator music). I copied over the connections for a SD card module from some locations online and ended up with this:

I didn't feel like rerouting and replacing components on my whole PCB, so I decided to just use a testpoint footprint. I made a custom 6 piece testpoint footprint that can fit under the ESP-32. Since there was nothing under it, routing was easy and looked like this:

After that, I updated the CAD to include the SD card reader. I just used the project tool to add in screw holes and a hole for the SD card to stick out. I also modified the arm to look better. This is what I have now:

I also went in and added a 0.1 press pull to the screw threads, as that is what has worked in the past.
I am done. I now need to begin budgeting.

1/24/2026 - Wrote firmware and added to PCB

Today, I did the BOM, which came out to be ~$75, and I completed the firmware. I was initially going to have an integration with Spotify, but when I started working, I found that I would need a premium account to get what I wanted. That's when I remembered that I included an SD card reader in the PCB, so I decided that this whole project could just work offline, using music downloaded to the SD card. This made everything much easier, as there is already a library for reading from an SD card and playing it out over i2s. I began by adding that, then I added in the RC522 NFC reader, the gesture sensor, the hall effect sensor, and finally the stepper motor. I created the following methods to make everything easier to read:

The last method, update visualizer, required a rework of the PCB. After checking how to get the audio level that was going out, ie the perceptible audio level, I found out that I would need to connect the OUTP pin of the MAX9753A to and ADC pin on the ESP32. This required me to update the schematic and PCB. This is what I added:

The diode converts the audio singal into something the ESP32 can read. The 10k voltage divider helps convert the high voltage down into a voltage that the ESP32 can safely take. This is what I added to the PCB:

I have finished the repo and am ready to submit!

2/4/2026 - UPDATE FOR REVIEWERS

Would it be possible to increase my budget by $6.34, making the total $85.46? I just learned that you need to select "different designs" when using a panelized/mousebites PCB, which has increased my cost. I have attached a screenshot of the new cart: