This past week, I spent time finalizing the system’s circuit architecture, researching components, and planning my approach for the PCB. The final PCB board will use an 8 × 8 matrix of Hall-effect sensors and LEDs, but I decided to begin with a 1 × 8 prototype. This will allow me to confirm that the sensors work properly and meet our 98% accuracy user requirement before ordering the complete board. A major concern is crosstalk, where a magnet may activate a sensor on a neighboring square. I compared linear analog sensors, which measure magnetic-field strength, with switch sensors, which produce a simple ON/OFF output. Although analog sensors could help identify which sensor has the strongest reading, they would require more processing and could increase latency (another user requirement). Since both accuracy and response time are important, I decided to use a switch sensor. I selected the 20 Hz DRV5032 digital omnipolar switch because it is sensitive, responds quickly, and is omnipolar. I also want to test the sensors physically before finalizing the PCB, so I plan to purchase/find SOT-23-to-3-pin DIP breakout boards. These will allow me to connect the sensors to a breadboard and test the complete 1 × 8 setup using an Arduino.
I am slightly behind schedule, although I completed this week’s main tasks: finalizing the circuit architecture and selecting the major components. The delay is mainly because I have not yet submitted the component order form. To catch up, I plan to meet with my TA on Monday to review my approach and component choices before submitting the form. Once the approach is approved, I will submit the order immediately and begin the PCB design while waiting for the components to arrive.
Next week, my main goal is to complete the 1 × 8 PCB array design by Friday. This includes designing both sides of the board, with the LEDs on the top and the Hall-effect sensors on the bottom. Since I have previous PCB design experience, I believe this is a realistic goal. In parallel, I also want to begin working on the design presentation, which is due next weekend. I will be presenting on behalf of my team, so I want to discuss each part of it with my teammates.