LEVEL 2

1 / 6 / 2025

Task 2- SPI Communication

• SPI (Serial Peripheral Interface) is a synchronous, full-duplex protocol used for fast communication between a Master (e.g., one Arduino) and a Slave (another Arduino).
• It uses 4 main lines:
  1. MOSI (D11): Master → Slave
  2. MISO (D12): Slave → Master
  3. SCK (D13): Clock from Master
  4. SS (D10): Slave Select (LOW to enable slave)
• Master controls the communication using SPI.begin() and SPI.transfer(), sending data while controlling the clock and slave selection.
• SPI is faster than UART/I2C, but allows only one master and needs separate SS lines for multiple slaves.
• SPI is widely used to interface microcontrollers with devices like microSD cards for data storage, OLED/TFT displays for fast graphical output, and sensors such as accelerometers and gyroscopes for real-time data acquisition.

Task 3- I2C Control

• I2C (Inter-Integrated Circuit) is a two-wire, half-duplex, synchronous communication protocol for connecting multiple devices on the same bus.
• It uses SDA (data line) and SCL (clock line) shared by all devices, reducing wiring complexity.
• Devices on the bus have unique addresses; one device acts as the Master to control the clock and initiate communication.
• Data is transferred in 8-bit packets with an acknowledge (ACK) bit after each byte to confirm reception.
• Commonly used for connecting sensors, EEPROMs, RTCs, and displays in embedded systems due to its simplicity and scalability.

Task 6 - Smart Active Battery Balancer

• Aim- To balance two unbalanced batteries
• Actively transfers charge from higher-voltage cells to lower-voltage ones.
• Arduino Uno monitors and equalizes the voltage levels of two unbalanced Li-ion cells, by intelligently controlling current flow with an IRF830 n-MOSFET and CL100 NPN transistor.

Task 7 - Regenerative Braking System Demo

• Aim- To demonstrate the concept of regenerative braking using a DC motor controlled by Arduino PWM.
• In electric vehicles, regenerative braking converts the vehicle’s kinetic energy into electrical energy during deceleration, instead of wasting it as heat.
• The motor acts as a generator, feeding energy back into the system.

Task 8- Interfacing STM32 Nucleo with L298N Motor Driver

• L298N is a dual H-bridge motor driver used to control the direction and speed of DC motors.
• STM32 Nucleo outputs PWM signals for speed control and digital pins for motor direction.
• The motor driver receives control signals and supplies the required current to the motors.
• PWM frequency and duty cycle from STM32 regulate motor speed smoothly.
• Direction pins (IN1, IN2) determine motor rotation direction (forward/reverse).

Task 9 - Interfacing STM32 Nucleo with Servo Motor

• Servo motors rotate to a specific angle based on the PWM pulse width received.
• STM32 Nucleo generates PWM signals typically between 1ms to 2ms pulse width at ~50Hz frequency.
• Changing the PWM duty cycle moves the servo shaft to the desired angle.

Task 10 - Configuring ADC in STM32 Nucleo Board

• ADC (Analog-to-Digital Converter) converts continuous analog voltages into discrete digital numbers.
• STM32 Nucleo’s ADC supports multiple channels and resolutions (commonly 12-bit).
• Configuration includes selecting the ADC channel, sampling time, and conversion mode.
• ADC conversion can be started manually or via hardware triggers.
• Digital values from ADC are used in firmware to interpret sensor readings or control algorithms.