Questions and answers
Why did you choose this microcontroller?
Compare on pins, memory, built-in Wi-Fi or Bluetooth, ADC resolution, cost and library support, for example ESP32 over Arduino Uno for built-in Wi-Fi.
What is the difference between a microcontroller and a microprocessor?
A microcontroller has CPU, memory and peripherals on one chip for dedicated control; a microprocessor needs external memory and peripherals and suits general computing.
How does your sensor work?
Explain its principle (resistive, capacitive, ultrasonic time-of-flight, infrared) and its output type, analog or digital.
What is ADC resolution?
The number of bits used to represent an analog value; a 10-bit ADC gives 1024 steps.
Which communication protocols did you use?
For example UART, I2C or SPI between devices, and Wi-Fi with MQTT or HTTP to the cloud. Say why.
What is the difference between I2C and SPI?
I2C uses two wires and addresses and is slower; SPI uses four wires with chip select and is faster.
How is the circuit powered?
Explain the adapter or battery, regulator (7805, AMS1117 or buck converter) and current budget.
Why are pull-up resistors needed?
To hold a line at a defined logic level when no device is driving it.
Explain the program flow.
Describe setup, the main loop, and what happens on each sensor threshold or interrupt.
What is PWM and where did you use it?
Pulse width modulation varies the duty cycle to control average power, used for motor speed or LED brightness.
How does the data reach your dashboard?
Device connects to Wi-Fi, publishes readings to a broker or API, and the app subscribes or fetches and displays them.
How accurate is your system?
Give the comparison with a reference instrument and the error percentage.
How did you design the PCB?
Name the tool, layer count, track width and how you tested continuity.
What happens if the internet fails?
Explain local fallback such as buffering, a buzzer or SMS.
What is the total cost?
Give the figure and the main components.
Related
Hardware and IoT project guidance · IoT project ideas
FAQs
Will the examiner check my code?
Usually they ask you to explain one function or change a threshold and show the effect. Know your own code.
Last reviewed: 2026-10-11. Always follow the format your own department gives you.