New Case!

• I updated the case so now the pcb is almost fully enclosed and I have the name of the board on the case now. Since the top part also extends over more of the pcb I added another screw hole to make sure the case is secure. I did leave a grate on the bottom right so you can see the LEDs even when the case is on, and I left a hole on the top right so that you can access the buttons which will eventually control the display. The hole next to the display is for the cable to attach to the connector on the pcb.

Cleaned up Schematic + Fixes

• I tidied up the schematic making it much easier to read and decipher and also found that the W25Q12BJVS was wired up wrong. I also figured out that pgnd is not supposed to just be gnd, and needs a “star grounding” which is basically where pgnd and gnd is separate except at one point where they connect so that the higher voltage from the motor drivers doesn’t interfere with the lower voltage grounds from logic chips. So I made the changes and added that too.
• I then worked on getting all these changes over to the pcb which was really annoying because some of the pins weren’t in the correct order and some of the resistors/capacitators were flipped so I had to manually go through and correct all that so the schematic would work as intended. I also thickened the traces from the motor drivers to the motor terminals because they were only 0.2mm thick traces (and should’ve been bigger because they’ve got to carry voltage to the motors).
• Next up I want to update the case that I CADed to be more of a full & cooler looking enclosure.

Updated PCB & Schematic + A CASE + BOM + Code

• So the first thing I noticed when I started making the BOM was that the voltage converters I had used (since I needed to convert 7-12V - 3.3V & 5V) were way more expensive than they needed to be so I spent some time looking for alternatives and eventually settled on 2 that were much cheaper. I also replaced the through hole capacitators (since they were hard, if not impossible to find), with surface mount ones.
• The unfortunate part of these changes was that I had already designed a case for the old design and even though they’re somewhat similar I decided to just design a whole new case which took even more time but eventually I got a case with a top and bottom part secured with M4 and M6 screws.
• I was initially going to use JLCPCB’s PCBA service where they assemble the PCB for you (because I hadn’t soldered before and didn’t really want to try first with 0402s), but it ended up being way more expensive than just learning to solder and doing it myself! I went through LCSC to get all the parts I needed and made a BOM with all the part links. I also created a github with all the files which you can find here: https://github.com/A-Ritvik/Mission-Board/tree/main.
• I also made some prelimenary code for the esp32 and rp2040 processors that prints out mag, accel, and gyro measurements to the display. It also features the ability to connect to a phone and move a specific motor if a specific command is sent. This code is pretty basic (but was still hard for me to make since its my first time coding something like this), but its main purpose is for me to learn a bit about how to code processors directly and to test that everything on the board is functional. Once I have the board and I can actually test the code, iterate on it, and debug it I hope to make it much more function so the board can fullfill its original mission of being a robotics control board!

Finished PCB and more Schematic Updates

• I realized a robotics control board should probably have debug lights so I added an led light to show 3.3v power, 5v power, 2 rgb lights that I’ll code later, and 2 led lights that I’ll also code later.
• I also spent a lot of time wiring the PCB and then went through DRC and fixed all the errors I could (although some of the errors were on the footprints themselves so not really sure what to do about that yet). I then designed some basic signage for the silkscreen on the PCB so it know shows which usb is for which, where the board gets power, and the motor ports. You can also see the 3d view of the finished PCB in the screenshot below but a few of the components are missing 3d models.
• Next up I’m probably going to go ahead and start building a case to house the board (although It’ll likely just be something minimal to house the display and to make sure I don’t cover up any ports on accident).

PCB wiring update & changes/fixes to the schematic
I spent a couple hours wiring the pcb only to realize that I had way too many capacitators and I was missing some critical functions from the schematic. So I went through and took out some capacitators from the schematic as well as adding an oscillator, dedicated quadspi to flash memory for the rp2040, and a usb-c port dedicated to upload code to the rp2040. I also fixed an issue where I had duplicate SPI from the esp32 to the display connector and rp2040 and instead made it so they share the clock, copi, and cipo.
The pcb wiring image is not updated yet from the schematic and I will need to do that as soon as I finish adding the footprints for all the new additions. So far I have added the 5v, 3.3v, and VM power rails and I made the traces there thicker. I’ve also wired up a lot of the logic for the motor drivers, the rp2040, and the switches. However, some it will most likely have to be redone because of the changes to the schematic :(.

Finished (hopefully) wiring up the schematic for the mission board!

As you can see from the schematic I had to make quite a few changes to the original plan, including the addition of an RP2040 as co-processor because the ESP32 itself didn’t have enough IO pins. The way its set up is that they can communicate through SPI and the RP2040 handles all motor controls while the ESP32 is the main brain. I also switched to a display that used the smaller 18 pin connector since its more practical. I also had to add 2 voltage converters which output at 3.3v (for board logic) and 5v (for servo power). The power input will come only from the barrel jack (not the usb-c) and the converters can handle from 7-30 something volts. I have decided that for this iteration of the board I’m also not going to include encoder ports because I want to start simpler and see if what I have right now will even end up working. Now my next plans are to start working on the PCB and make a case for the board!

Made a sketch for the board along with a hardware list (more stuff will probably be added), and setup the schematic with all the symbols I need

• After deciding I wanted to make a robotics oriented dev board I added motor drivers, screw in terminals, usb-c, a barrel jack(for power), pins to connect a servo, gyro, magnetometer, accelerometer, and at the center of it all: an ESP32-S3-WROOM. I chose this option because it supported usb, had wifi/bluetooth, and could potentially process camera feed to allow for a robot with a camera.
• I also added a 7 switches to interact with the UI that I will develop in the future for the display to be functional at actually making debugging & customization easier
• Also worth noting is that not everything in my sketch is in the schematic right now, because I wanted to start with at least the basics and core of my devboard. However, in the near future I will be adding all the stuff you see in my sketch.
• Now I’m going to start working on the actual schematic, and along the way I’ll probably add some stuff for the power system as well