How to Explain Your Project During the Viva
The questions examiners actually ask, in the order they usually ask them, and how to prepare answers that hold.
Your opening ninety seconds
Almost every viva starts with "explain your project". Have a ninety-second answer prepared that covers four things in order: the problem, what your system does about it, how it works at block level, and what your results showed.
Do not start with the components. Starting with "we used an Arduino Uno and a DHT22" tells the examiner what you bought, not what you built, and it invites component-level questions before you have established the bigger picture.
The questions that come up nearly every time
- Why did you choose this component over the alternatives?
- What happens if this sensor fails or gives a wrong reading?
- Why this threshold value? Where did the number come from?
- What is the accuracy, and how did you establish it?
- What are the limitations of your project?
- What would you do differently with another month?
- Show me this part of your code and explain what it does.
- Can you change this setting and demonstrate the new behaviour?
Be ready on your numbers
Threshold questions catch more students than anything else. If your project triggers at a particular sensor value, know where that value came from — a calibration measurement, a datasheet figure, or a test you ran. "That is what the tutorial used" is the answer that goes badly.
Write your calibration procedure down while you are doing it. Two lines in a notebook at the time saves a difficult minute months later.
When you do not know
Say so, then say what you do know and how you would find out. "I did not measure that, but I would test it by doing X" is a respectable answer that examiners hear far less often than they should.
What does not work is guessing confidently. Examiners follow up on answers that sound uncertain, and a wrong answer delivered firmly turns one question into five.
Running the demonstration
- Set up and test before the examiner arrives, not while they watch.
- Have a manual override or a way to force the trigger condition — do not rely on ambient conditions cooperating.
- Carry spare batteries, spare jumpers and a screwdriver.
- If something fails, say what you think is wrong and keep talking. Diagnosing it aloud recovers more marks than silence.
