Ananda Teertha's EV-RE Level 1 Report
11 / 10 / 2026
Task 1: LTspice and KiCad
Objective: Design and simulate a 555 timer-based astable multivibrator using LTspice to observe frequency and pulse width behavior. Use KiCad to create a schematic of an LED blinking circuit and design a PCB layout with proper footprints and routing.
Softwares used: LTspice and KiCAD
Outcomes and Learnings: I understood the working and applications of 555 timer in different modes. There are mainly 3 modes of operationn of a 555 timer and they are: Bistable, Monostable and Astable. These modes are classified based on the resistors and capacitors connected to the Integrated circuit.
Astable Mode: In this mode, the timer acts as an oscillator oscillating between high and low outputs. It consists of connecting 2 resistors and 1 capacitor to the IC as shown below.
The output and capacitor waveforms can be observed in the above image. The output waveform keeps oscillationg between High(1) and Low(0) whereas the capacitor voltage varies between 1/3rd and 2/3rd of Vcc values.
Simulations:
LTspice
As my resistor values are R1 = 10kΩ and R2 = 18kΩ, the Duty cycle is calculated as
D = (R1+R2)/(R1+2R2) = 60.8%
KiCAD
The PCB of the above circuit is as follows
Reference:
- Click Here for detailed explanation of all modes of 555 timer.
- Click Here for PCB design.
Task 2: Point Turn of a Vehicle with Ultrasonic Sensor (Embedded)
Objective: Build an obstacle-avoiding robot using an HC-SR04 ultrasonic sensor, Arduino, and a motor driver. The vehicle should detect obstacles and perform a point turn by rotating in place to change direction. It combines sensor data processing with differential motor control.
Software used: Arduino IDE
Outcomes and Learnings: I understood the working of the HC-SR04 ultrasonic sensor which which containg Ultrasonic Transmitter and Reciever. The distance is calculated by the time taken to transmit and recieve the high frequency sound pulse. By applying this concept, I made the circuit work in such a way that when an obstacle is less than 20cm from the sensor, the sensor detects it and sends data to Arduino Uno which prompts the Servo motor to rotate from it's natural 90 degree position to 150 degree angle and then after a short delay it returns back to its position.
This task demonstrates the working of obstacle avoiding robot where the servo motor acts as the robots steering mechanism which steers away from any obstacle in the path of the robot automatically.
Below are the pictures and videos of my work.
Task 3: Temperature and Humidity Detection (Embedded)
Objective: Use the LM35 analog temperature sensor to monitor ambient or localized heat (e.g., near a soldering iron). When temperature exceeds a threshold, turn on an LED using a BJT as a switch. In parallel, use the DHT11 digital sensor to read and display temperature and humidity on a 16x2 LCD.
Softwares Used: Arduino IDE
Outcomes and Learnings: LM35 Analog sensor The LM35 is an analog temperature sensor that outputs an electrical voltage linearly proportional to the Celsius.
Working Principle: The LM35 outputs 10 mV for every 1 degree increase in temperature. For example, if the temperature is 25 degree Celsius, the LM35 will output 250 mV.
I rigged up a circuit which measures the temperature using LM35 and Arduino and also added a LED along with a Transistor which when the temperature exceeds the set threshhold (35 degrees Celsius)- the LED glows indicating the high temperature. The task is done as shown
DHT11 Digital Sensor The DHT11 sensor is a low-cost, popular digital device used to measure ambient temperature and humidity.
Working Principle: The DHT11 houses two primary physical sensing elements and an internal 8-bit microcontroller to convert analog readings into digital data
Humidity Sensing (Capacitive): It uses a moisture-holding substrate (such as a polymer film) sandwiched between two electrodes. When water vapor is absorbed by the substrate, ion mobility changes, altering the capacitance. Higher humidity raises the dielectric constant and capacitance, which the internal chip converts to a relative humidity percentage.
Temperature Sensing (Thermistor): It uses a Negative Temperature Coefficient (NTC) thermistor. As room temperature rises, the internal resistance of the thermistor drops. The internal IC reads this resistance change and converts it into a temperature value.
Due to the unavailability of an LCD display, I showed the temperature and humidity values on serial monitor of Arduino IDE. Here are the pictures of this task
Task 4: BLDC Motor And Hall Effect Sensor (Embedded)
Objective: Connect a BLDC motor with a Hall effect sensor to measure its speed. The output of the Hall sensor is read by Arduino to calculate RPM and display it via the Serial Monitor. This task demonstrates motor speed sensing and signal interpretation.
Software used: Arduino IDE
Outcomes and Learnings: A Hall effect sensor works on the principle that when a current-carrying semiconductor is placed in a magnetic field perpendicular to the current, a small voltage called the Hall voltage is produced across it.
In a BLDC motor, small permanent magnets are attached to the rotor, and Hall sensors are placed on the stator. As the rotor rotates, the magnetic field passing through each Hall sensor changes. This makes the sensor output a sequence of HIGH and LOW pulses.
The speed of the motor is found out using the formula
N=120f/P
Where,
N= Speed in RPM
f= Frequency of Hall pulse
P= Number of poles of the motor
Here is the working of the task
Task 5: Battery Capacity Measurement (Power Electronics)
Objective: Monitor the voltage of a Li-ion battery using analog input on Arduino. Use a MOSFET as a switch to disconnect the load when voltage drops below a safe threshold. Ensures safe battery operation and demonstrates basic battery protection logic.
Softwares Used: Arduino IDE
Outcomes and Learnings: In the task, the Arduino measures the Li-ion battery voltage through a voltage divider, and when the battery drops below a chosen threshold, it turns a MOSFET OFF to disconnect the load.
Due to this task requiring different voltage levels to showcase MOSFET turning on or off, I used a VRPS to show the working of the task where I had set the threshhold as 3.2V, the Arduino continuously monitors to check if the voltage is above 3.2V and the load which was an LED in my case would turn off when the output of VRPS is less than 3.2V.
This is the circuit diagram, the voltage divider is an integral part of the circuit as it is required for the protection from high voltage.
Here's my task
Task 6: Battery Charging (Power Electronics)
Objective: Charge the Li-on battery using solar panels and a solar charging module.
Outcomes and Learnings: I demonstrated the charging of a Lithium-ion cell using a solar panel and a TP4056 solar charging module which controls charging voltage/current and prevents inappropriate charging.
As I only had access to a 3V solar panel- It was not enough to charge the cell which is around 4.2V at full charge. Hence the readings in the mutimeter are stable but the working of circuit can be seen by the Red light glowing on the Charging module which indicates that the cell is in charging mode.
Task 7: Solar Tracker (Embedded)
Objective: Use LDRs and a servo motor controlled by Arduino to orient a solar panel toward the strongest light source. The system maximizes solar energy collection using dual LDR comparison logic and basic actuator control.
Softwares Used: Arduino IDE
Outcomes and Learnings: The solar tracking system uses two Light Dependent Resistors (LDRs) to detect the intensity of light from different directions. The LDRs are connected to the analog inputs of an Arduino, which continuously reads and compares their output values. A small divider between the LDRs helps create a difference in light intensity when the light source is not directly in front of the panel.
The Arduino determines which LDR receives stronger light and controls a servo motor accordingly. If the left LDR receives more light, the servo rotates the solar panel toward the left, and if the right LDR receives more light, it rotates toward the right. When both LDRs receive nearly equal light intensity, the servo stops moving, indicating that the panel is oriented toward the strongest light source.
Thus, the system automatically adjusts the position of the solar panel to maintain better alignment with the light source, helping maximize the amount of solar energy received. My task is as shown below
Task 8: Simple Electric Circuits Simulation on MATLAB (Power Electronics)
Objective: Learn the basics of Simulink in MATLAB by designing a simple RLC or transistor-based circuit. Simulate voltage, current, and frequency responses over time using virtual probes and scopes.
Softwares Used: MATLAB Simulink
Outcomes and Learnings: MATLAB (Matrix Laboratory) and Simulink are two connected software tools made by MathWorks for technical computing, data analysis, and system design. MATLAB uses a text-based programming language for math and data, while Simulink provides a visual, block-diagram environment for simulation. I simulated a Single-phase Inverter which converts the input DC signal to an AC signal in Simulink. The Inverter consists of a DC supply and 4 MOSFETs which are turned on and off using gate pulses at different intervals so that we can obtain an AC voltage output.
Here is my simulation
And the obtained waveformas are as follows
