assignment

individual assignment: measure something: add a sensor to a microcontroller board that you have designed and read it

group assignment: probe an input device's analog levels and digital signals

[1] Looking at the weeks to come, I decided to attempt creating a large new board with many pins that I could potentially use for both my final project, but also for Input/Output and Networking. For this, I decided to use an ESP32 microcontroller which has many pins that can be used for almost anything I might need, and also which has WIFI/Bluetooth for Networking week. ESP32 also has the added benefit that it doesn’t require programming using a bootloader, which was something I struggled with when I created my ATTtiny and D11. Although I had already designed and milled a board before, I had mostly based my design on an existing board, adding only an LED light and a button.

For this reason, creating a board from scratch for the ESP32 was a lot harder than I imagined. As I had focused on Latin America earlier, I wanted to continue pursuing this theme, and designed my board to be shaped like South America, the South American ESP32 PCB. For this board, I mostly followed the steps described in Week 5, with a couple of differences. I learned that it is very difficult to have Ground and Voltage pins next to Pin Headers all around the board, so I only included ground and voltage headers in a couple of places and then in the southern tip of the South American PCB, I created a few pins all dedicated to ground and a few pins all dedicated to voltage.

As the ESP32 board I was designing receives 5V through UPDI, but the ESP32 chip can only take 3V, I had to include a regulator. Understanding this was a crucial step. Also, it made me realize that it would be a good idea to have header pins for both 5V and 3V; as some Output and Input sensors might require different voltage.

Being able to create the traces for all the different headers I wanted, while maintaining the shape of South America was more difficult than I thought. I ended up using 2 different 0 ohms resistors to be able to bridge traces that I couldn’t connect otherwise. I also used the space under the ESP32 to run traces from one side of the board to the other. A problem I faced this week, was that I didn’t know I couldn’t flip components. I was so used to CAD software/3D modeling, that during the design process, I flipped some components to be able to maintain and achieve the desired shape.

After milling, soldering, and creating the final version of my South American board, I realized the problem with using the flip (mirror) functionality. As I had flipped the components, the ESP32 was soldered incorrectly. I had spent a lot of time developing this board and needed to have an Input device. So, I decided to mill the ESP32-Cam board on the HTMAA website and play around with capturing images. I will have to delay fixing the board I was designing for Output Week.

Update: After creating/designing my own board for output week, I came back and added a temperature sensor to that board to have temperature as an input. This made me think I could add temperature as well as the ESP32-Cam to my final project.

Considerations:

-Add both 3V and 5V header pins to a board you design.
-Don’t flip components in KiCad, flipping/mirroring is only to be used to design two-sided board. Again, I think I need to learn how to design and mill two-sided boards at some point.

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