This week, we received the parts we ordered from DigiKey for our Traffic Light Circuit, and I placed the order for our custom PCB after making a couple of small adjustments to the Arduino pin assignments and silkscreen text placements. The fabricated PCB should be arriving within the next week, and when it does, I will solder on the LEDs, resistor, LED driver chip, and Arduino stacking header pins. Here are renders from OSH Park (the PCB manufacturer we used) of the bottom and top of our board:

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Once I have assembled the completed circuit on our PCB, I can begin testing that the Arduino code I’ve written controls the LEDs with the desired behavior, and with minimal delay time between input and output updates. I am nearly done with writing the code that allows the RPi to communicate with the Arduino as well as the code that interfaces between the Arduino and the LED driver chip. I used an OOP approach to define data structures that can store the necessary information about the states of each model Traffic Light and the Intersection as a whole. Here are some of the structs/classes I have defined in the header file:

And here are some of the functions used to initialize/modify the data stored in them:

Lastly, here is an example of how I am piecing it all together to generate the final output that goes to the LED driver via SPI communication:

Once I have finished writing these interfaces, I will write a testbench to ensure that we observe the expected behavior before I actually hook the Arduino up to the PCB circuit. My plans for the next week are to complete the coding and verification processes, as well as to assemble the PCB so that I can begin testing the integrated system.

This week I was focused on doing the layout for our custom PCB that connects the ArduinoUNO to the 12 traffic-light-simulation LEDs via a Texas Instruments LED driver. This is my first time doing PCB layout myself, so it was a bit challenging at first to get used to, but I have learned enough about it at this point that I am confident our PCB will function as intended. I am almost done putting everything in its correct place and making sure everything follows the proper design rules and specifications of the PCB manufacturer we will be ordering from (OSH Park). I have inserted a picture of my progress below:

I will have the PCB layout finished and submit an order for it by Tuesday of this week so that we hopefully receive it before the interim demo in a couple of weeks. If it doesn’t arrive by then, we will just do our demo using the breadboarded LED circuit. Once the PCB is ordered, my goal for next week is to write the Arduino code that drives the LEDs. I am also a bit behind on getting some traffic videos at Fifth and Craig for Ankita to use to train the object detection model, but I acquired a GoPro from the IDeATe lending desk at Hunt and will get those videos for her as soon as possible.

This week we were still in a very preliminary phase of researching/purchasing/planning before we can begin work on our implementation. We settled on the IP camera to order, ordered it, and reserved an RPi. I also did some research on Addressable LED Arduino projects and will be placing an order for Addressable LEDs in the next few days. Lastly, I worked with my teammates to finalize our design plans regarding the overall testing approach. With these ideas in mind, we worked on our Design Review presentation to summarize our current plans for the implementation and testing approaches.

In the next week, Ankita and I will get the RPi hooked up to the IP camera over WiFi to make sure that we can receive/process video footage in real time. We will then test the camera for things like image quality, data transfer latency to RPi, and battery life. I will also begin working on the Arduino code that can take in incoming information packets (simulated for now, but eventually from the RPi) and translate them into corresponding changes for the Addressable LEDs. Before I can actually begin coding, though, I need to determine a rigorous set of rules regarding should be legal/illegal for our light control system to do. Once the code is working, I will breadboard the Arduino to some standard LEDs to simulate a four-way intersection for testing.