Summary
Summary
Embedded Files
Hello, I'm Sonal Tamrakar. I'm a second year graduate student at CU Boulder, specializing in Embedded Systems within Electrical and Computer Engineering. Below, you'll find a collection of the PCB designs I have created during my studies. For each PCB, I have included a description of the class it was associated with and a summary of the project. Additionally, I have included lab reports from my classes such as Practical Printed Circuit Board Design + Manufacture, Low Power Embedded Design Techniques, Embedded System Design, and Senior Capstone 1/2. These projects showcase my hands-on experience and skills in PCB design and implementation over the past five years at CU Boulder.
ECEN 5730 (Practical Printed Circuit Board Design and Manufacture): A custom Arduino shield was built incorporating a 16-bit ADC, 12-bit DAC, I2C-driven heart rate sensor, hall effect current sensor, a CO atmospheric sensor, a temperature and humidity sensor, a microphone, and nine RGB Neopixel LEDs. (4-layer board stackup designed in Altium Designer)
ECEN 5833 (Low Power Embedded Design Techniques): A portable mobile solution with functionalities such as GPS location tracking using a SAM-M8Q UART module, an I2C-driven MAX-30101 heart rate sensor, a BME280 temperature and humidity sensor, power conditioning subsystem using BQ25570, an EFR32BG13 microcontroller for BLE communication, and an inverted F-antenna with impedance matching for connecting the device to a phone BLE application (2-layer board designed in Altium Designer)
ECEN 4620 (Senior Capstone): Comprehensive board featuring an MCU based on the TMS320F280049 which includes components such as an FTDI UART-to-USB interface for communication, 12V/48V barrel jack input. The board incorporates a phase-shifted full bridge for power conversion, complemented by a JTAG cable to facilitate software debugging. (4-layer board designed in Altium Designer). Not shows: RF Tank PCB
ECEN 5613 (Embedded System Design): Vehicle monitoring system with MPU6050 accelerometer, UART based GPS module NEO-6M, and SD card data storage using SPI (FatFs). The board includes a 9V/12V barrel jack, 5V buck regulator, and acts as a shield for the STM32F Discovery Board. (2-layer board designed in Altium Designer)
ECEN 5730 (Practical Printed Board Design and Manufacture): An Arduino board built with the best design and layout practices. The board implements the ATMEGA328P microcontroller chip that most Arduinos have and is designed to reduce crosstalk and switching noises on the power rail. (4-layer board stackup using Altium Designer)
Research: This research project focuses on developing a specialized circuit board designed to measure power rail noise. The board serves as a shield placed on top of a commercial Arduino and includes a 12V barrel jack connector. It features a MOSFET driver circuit to generate high-current, low-duty cycle pulses. The primary goal is to demonstrate the importance of effective decoupling techniques in PCB design. This work explores advanced methods in noise measurement and mitigation, highlighting practical applications in electronics reliability and performance enhancement. (2-layer board stackup using Altium Designer)
Past Board Design Layouts
MCU Evaluation 4-Layer Board: Phase 1 evaluation board for capstone/senior design class which incorporates the TI Piccolo uC. Some important features of this board includes the FT232RL FTDI chip to enable serial communication between the MCU and the host computer. An H-bridge is also implemented with an AND gate chip and two FET drivers which will be used to control the Phase Shifted Full Bridge.
4-Layer Arduino Shield: Incorporates sensors and ICs such as a heartbeat sensor, buzzer, microphone, 16-bit ADC, 12-bit DAC and a CO sensor.
Slammer Circuit Board: The board consists of 'slammer' circuits that draw high amounts of currents in short period of time. Two MOSFETs and a BJT is utilized and separated into three similar circuits. Decoupling capacitors are added to reduce the high amounts of voltage noise on the power rail. The circuit is tested with and without the decoupling capacitors to measure the difference.
555 Timer Board: On this board, the NE555 timer is used as an astable vibrator that drives the four LEDs. The series resistance with the LEDs are varied to measure the relative brightness and as well to measure the total current draw from the output pin of the 555 timer.
Golden Arduino: An Arduino board built with the best design and layout practices. The board implements the ATMEGA328P microcontroller chip that most Arduinos have and is designed to reduce crosstalk and switching noises on the power rail.
Good/Bad Switching Noise Board: The purpose of this board is to show the difference between good and bad layout in designing PCBs. There are two identical circuits that are laid out differently which affects in the amount of switching noise on their IC pins.
TVS Diode Breakout Bread for testing purposes
Motor Driver for Adafruit CLUE: The micro:bit external motor driver board that gives the user a robot platform to build their circuits. Features include servo motors, full H-bridge, edge connector to the micro:bit and I2C functionality.
Name Tag Board 2: Prototype 2 with LEDs implemented + QR code. LEDs are lit up using an ATtiny85 8-bit microcontroller on the back of the board.
Labs/Lab Reports/PCB Reports
Labs/Lab Reports/PCB Reports
Board 1: 555 Timer Circuit Final Report
ECEN4730_Board1_Report_Tamrakar_Sonal (1).pdfBoard 2: Hex Inverters GOOD and BAD layout practices on a circuit board
ECEN4730_Board2_Report_Tamrakar_Sonal.pdfLab 18 Report: Single ended vs. differential measurement techniques
ECEN4730_Lab18_Report_Tamrakar_Sonal.pdfLab 7 Report: Measuring trace resistance through 2-wire and 4-wire method, and blowing up traces
ECEN4730_Lab7_Lab_Report_Tamrakar_Sonal (1).pdfLab 4: Power Delivery Network (PDN) and slammer circuit lab
ECEN_4730_Lab4_Report_Sonal_Tamrakar.pdfLab 6: Good/Bad Switching noise Lab
ECEN_4730_Lab6_Report_Sonal_Tamrakar.pdfLab 16 Report: Making and analyzing button debounce on mechanical switches, and demonstrating the use of filter capacitors to filter out high frequencies.
ECEN4730_Lab16_DebounceLabReport_Sonal_Tamrakar.pdfEmail: sonal.tamrakar@colorado.edu
LinkedIn Profile: www.linkedin.com/in/tamrakarsonal77
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