Questions & explanations
1. How do you choose between an interview and a survey for a research project?
Choose an interview when you need deep, detailed answers from a small number of people, like five to ten users. It helps explore new problems or understand a specific issue deeply. For example, if you want to find out why people stop using a app, an interview lets them explain in their own words. Choose a survey when you want to measure how common a problem is among many people, like 500 users. Surveys are faster and cheaper per person, but they give less detail. So if you need numbers and broad trends, use a survey; if you need rich stories, use an interview. Many studies start with interviews to find issues, then a survey to measure them.
2. Why is it important to combine different research methods in the analysis stage?
Combining methods gives a more complete understanding of users. Each method has strengths and weaknesses. For example, interviews give deep insights but from few people, while surveys get data from many but may miss context. By using both, you can first interview a few users to find what matters, then survey a large group to see if these issues are widespread. Observation (ethnography) adds real-world behavior that people may not report correctly. Together, these methods reduce the risk of designing based on wrong assumptions. A mixed approach saves time and money by making sure the product solves real problems for many users.
3. What is physical prototyping?
Physical prototyping means making a real, hands-on model of a product using materials like foam, clay, or cardboard. It helps designers test shape, size, and function before making the final product. For example, a designer might carve a rough foam model of a phone case to see how it feels in the hand. These models are quick and cheap to change, so designers can try many ideas. Physical prototypes are different from computer drawings because you can touch and hold them. This helps find problems early, like a button that is hard to reach. Overall, physical prototyping is a key step to check if a design works in the real world.
4. Explain how to design a snap-fit that can be easily disassembled without tools.
For tool-less disassembly, design a snap-fit with a push-button or a flexible latch that a user can press with a finger. The latch should have a shape that lets the user push it to release the hook. The hook must be angled so that pulling the parts apart applies force to open the latch. However, this can be tricky because the same angle affects how easily it snaps together. A good approach is to use two separate actions: one to snap together, and a different one to release. For example, a small tab that you slide sideways to release the hook. Testing is important to make sure the release force is easy for a person to apply.
5. Compare dynamic and condenser microphones for recording a podcast at home.
Dynamic microphones are tough and do not need external power, so they are easy to use and less sensitive to room noise. They produce a warmer sound but may miss some high-frequency detail. Condenser microphones are more sensitive and capture a wider range of sounds, making them better for capturing voice nuances, but they need power (phantom power) from the recorder. They also pick up background noise more easily, so they work best in a quiet room. For podcasting at home, a dynamic mic is often recommended because it rejects room echo and is simpler to set up. A condenser can be used if the room is treated for sound.
6. How can interviews be used in the analysis stage of product design?
Interviews involve asking people questions one-on-one to learn their opinions and experiences with a product. For example, you might interview five people who use a coffee maker to find out what they like and dislike. The researcher prepares open-ended questions like 'Tell me about your morning routine with the machine.' This gives in-depth answers that reveal what people really think. Interviews are good for exploring new ideas because you can ask follow-up questions. However, they take time per person and you cannot interview many people. The results help the design team understand user motivations and pain points.
7. Give an example of how a device manages power to make a battery last longer while still performing well.
A typical laptop uses power management software that lowers the processor speed when doing simple tasks like typing, and ramps it up for gaming. It also dims the screen when on battery and turns off the keyboard backlight after a few seconds. The Wi-Fi radio can be set to automatically turn off when a wired connection is used. Some devices use a 'dark mode' on OLED screens to save power because fewer pixels are lit. Additionally, the operating system may put unused programs to sleep to reduce background activity. Together, these techniques can double the battery life compared to running everything at full power.
8. How does lens aperture affect the brightness and depth of field in a photograph?
Lens aperture is the opening that lets light into the camera. A larger aperture (like f/1.8) lets in more light, so the picture is brighter and can be taken in dim conditions. It also creates a shallow depth of field, meaning the subject is sharp but the background is blurry, which is great for portraits. A smaller aperture (like f/8) lets in less light, so you need more light or a longer exposure, but it keeps everything from front to back in focus, useful for landscapes. Aperture is written as f-number: lower number means larger opening. Smartphone cameras often have fixed large apertures to work in low light.
9. Explain the role of miniaturization in modern smartphones.
Miniaturization is what makes a smartphone contain a powerful computer, camera, and many sensors in a thin body. Advanced integrated circuits pack billions of tiny transistors onto a chip the size of a fingernail. This allows the phone to run complex apps without overheating or draining the battery quickly. Smaller chips also free up space for a bigger screen and battery. The camera module is miniaturized to fit lenses and sensors in a slim bump. Every internal part, from the processor to the memory, is made as small as possible. Without miniaturization, a smartphone would be too bulky to carry in a pocket.
10. How does a microphone work to turn sound into an electrical signal?
A microphone has a thin membrane that vibrates when sound hits it. The vibration changes some property of the microphone, like the distance between two plates in a capacitor (condenser mic) or the position of a coil in a magnetic field (dynamic mic). This change creates a small electrical voltage that matches the shape of the sound wave. That voltage is then amplified and turned into a digital signal for recording or transmission. Condenser mics are more sensitive and used in phones, while dynamic mics are tougher and used on stage. The choice depends on the sound quality needed and the environment.
11. How does Design for Serviceability differ from Design for Assembly?
DFA focuses on making initial building fast and cheap, often using permanent joints like snaps or welds. DFS focuses on later disassembly for repair, so it may need screws or clips that can be undone multiple times. For example, a DFA snap-fit might be great for factory assembly but hard to open without breaking. DFS would choose a fastener that allows opening and closing repeatedly. DFA also tries to reduce part count, while DFS might add extra parts like a cover panel for access. Both are important, but they sometimes need different solutions. Designers must balance easy assembly with easy repair.
12. What is ethnographic research in product design?
Ethnographic research means watching and talking to people in their own real environment, like at home or work, to understand how they naturally use products. Instead of asking direct questions, the researcher observes behavior. For example, a designer might watch how a family cooks dinner to find problems with kitchen tools. This method uncovers hidden needs that people might not mention in a survey. Ethnography gives rich details, like how someone holds a tool or struggles with a button. It takes time but reveals true habits. The findings help designers create products that fit real-life routines.