Exercises: Home automation, IoT and artificial intelligence

Explain what home automation is using three concrete examples of a smart home (blinds that lower at sunset, heating that turns on before you arrive, lights that respond to voice) and what the three have in common.

The figure shows a house with several home automation devices connected to each other through a central element, which appears hidden by a question mark.

Answer:

1. a) Name the hidden element in the center of the installation.

1. b) Explain what information that element receives from the sensors and what orders it sends to the actuators.

1. c) Classify the devices labeled in the figure into sensors and actuators.

Classify these home automation devices into sensor or actuator, and justify two of them: a motion detector, a motorised blind, a camera, a smart plug that switches power off or on, and a water leak sensor.

Explain what the Internet of Things is (everyday objects connected to the network: fitness trackers, fridges, smart speakers, light bulbs) and what those objects can do thanks to the connection that they could not do before.

List four advantages of a smart home — comfort, energy savings, security and accessibility for elderly people or those with reduced mobility — and develop one of them with a concrete example.

Explain in your own words how an artificial intelligence system learns: just as a young child learns what a dog is by seeing many different dogs, the system learns from examples. What does it need in large quantities to learn well?

Describe the complete chain when you ask a voice assistant for something: voice → conversion to text → understanding the command → action → response. Indicate at which step it can fail if there is noise or an unusual accent.

State whether these statements are true or false and justify each answer: (a) the Internet of Things only exists inside homes; (b) a "smart" device always makes better decisions than a person; (c) sensors in a smart home record data even if nobody is looking at them; (d) a connected light bulb can receive commands from another country.

The figure shows how a home artificial intelligence learns: over several weeks, it records when the lights are turned on, when the blinds are lowered and the temperature of the house.

Explain what the system will have learned in order to make the covered prediction (anticipating routines: for example, heating the house just before the family arrives), why it needs many examples from different days, and what risk is involved in recording the life of a household in such detail.

Compare a programmable thermostat (obeys fixed schedules) with a smart thermostat (learns when you are at home). Explain what data the second one uses, what energy savings it achieves by not heating an empty house, and what happens if your routines change suddenly, such as during holidays.

You want to train a system to distinguish the family dog from the cat on the living room camera. Explain what examples you would give it (many labelled photos of each, in different poses and lighting), what the system would learn from them, and why it would fail if you only show it photos taken during the day.

A home automation "scene" called "leaving home" switches off the lights, lowers the blinds and arms the alarm with a single command. Explain what a scene is, what advantage there is in grouping actions, and design another scene called "night" with at least four ordered actions.

A smart speaker is always listening for its wake word, and an indoor camera records the living room. Analyse what data leaves that house and where it goes (the manufacturer's servers), what "the mic only activates with the wake word" means, and what settings you would review before installing them.

A home has ten connected devices that consume an average of $2\ \text{W}$ each in standby mode, $24$ hours a day. Calculate the daily and annual consumption in kWh and their annual cost at $\$3$ per kWh, and assess whether this "permanent toll" is worth it depending on how they are used.

The internet goes down in a smart home. Analyze which functions continue to work (those decided locally by the control unit: schedules, basic scenes) and which ones stop working (commands from a cell phone outside the home, cloud voice assistants), and explain what it means to design a system that is "proof against network outages".

Your family buys a light bulb from one brand, a plug from another and a speaker from a third, and they do not communicate with each other. Explain what a common standard or protocol is, why brands are slow to adopt it, and what you would look for on the box before buying the next device.

Your 78-year-old grandmother lives alone. She usually wakes up between 7:30 and 8:30 a.m. to have breakfast and take her medication. She wants to maintain her independence without feeling watched by cameras or microphones. Design a non-invasive home automation telecare system:

1. a) Select three different types of sensors (with no image or sound capture) and specify their strategic locations in the house.
2. b) Write the algorithm or logical flowchart (using IF... AND... THEN... conditions) so that the system is able to distinguish between a normal morning, simply waking up late, and a possible fall in the bathroom.
3. c) Justify what time thresholds you would assign to each alert and who should receive the various notifications to ensure safety without generating false alarms or violating her privacy.

An artificial intelligence model has been trained to control the automated irrigation of a school garden during spring, using soil moisture, ambient temperature, and solar radiation measurements. In early summer, a sudden heatwave occurs (temperatures of 41.5 °C) accompanied by a short but very violent storm (15 minutes of torrential rain that puddles the surface but does not soak in deep).

1. a) Predict two incorrect decisions the AI could make in this anomalous situation if its training did not include extreme events.
2. b) Explain how training data bias influences the predicted failures.
3. c) Design a high-priority safety control rule (independent of the AI) that locks the system to prevent plants from dying due to root asphyxiation or thermal stress.

A family purchases a smart thermostat and an electronic lock managed entirely through a start-up's cloud service. Two years later, the company goes bankrupt and shuts down its servers permanently.

1. a) Analyse the technical and security consequences that the home will face after the service shutdown ('bricked device' effect).
2. b) Based on the logs collected by the thermostat (desired temperatures, activation times, geolocation of linked phones), deduce what private information about the family's routine and habits is exposed if the database is liquidated and sold to third parties.
3. c) Justify why a local home automation architecture (with a hub in the home itself) offers greater resilience and privacy compared to a 100% cloud-dependent solution.

A cybercriminal manages to gain access to a home network by compromising a cheap Wi-Fi light bulb whose firmware was never updated.

1. a) Explain the technical principle by which such a basic device can be used as an entry point (pivoting) to intercept data traffic from the home's computers or mobile phones if they share the same network.
2. b) Design a network configuration proposal for the home router (using subnetting, VLANs, or a guest network) that isolates Internet of Things (IoT) devices.
3. c) Justify why using specific mesh home automation protocols (such as Zigbee or Z-Wave connected to a gateway) reduces the attack surface compared to connecting 30 devices directly via Wi-Fi.

Design the "vacation mode" for a house: lights and blinds that simulate someone being home. Explain why slightly randomized schedules trick people better than fixed ones (nobody turns on the light every day at the exact same time) and what other details would give away an empty house even if the lights turn on.

Evaluate the monthly energy balance of a home that has installed home automation:

• System's own consumption: 1 central controller with a continuous consumption of 4.5 W; 10 smart plugs/relays of 0.8 W each in standby; and 4 permanently connected sensors consuming 0.5 W each.

• Savings achieved: automating the electric water heater (1500 W) so it does not keep water hot during 5 off-peak hours a day when no one uses it, reducing its effective heating time by 1.2 hours per day; and cutting unnecessary heating use (2000 W) by 40 minutes per day thanks to open window detection and presence sensing.

1. a) Calculate the total energy consumed per month (30 days) exclusively by the operation of the home automation equipment in kWh.
2. b) Calculate the total energy saved per month in kWh thanks to the automations of the water heater and heating.
3. c) Determine the net monthly balance in kWh and in pesos (at an average price of 0.16 pesos/kWh). Conclude whether the installation represents real savings or an unjustified parasitic consumption.

A home energy monitor continuously records the demanded active power (kW). During the night (from 01:00 to 06:00 h), normal baseline consumption oscillates rhythmically between 0.08 kW and 0.22 kW due to the refrigerator compressor cycles.

• Case A: On a Tuesday at 02:40 h, consumption suddenly jumps to 2.4 kW and remains constant without dropping for four consecutive hours.

• Case B: For three consecutive nights, night consumption no longer cycles downward: it stays pinned continuously at 0.38 kW.

1. a) Interpret the data and propose a well-founded technical hypothesis for each case regarding which device or physical anomaly (breakdown, leak, insulation failure, or device left on) is causing that curve.
2. b) Design the automatic action protocol that the home automation system should execute for Case A before alerting the user, explaining which actuators it would involve to prevent a serious accident.

A family with two teenage children decides to integrate three virtual assistants with speaker and microphone into their home.

1. a) Choose with justification two rooms in the house where it would be technically functional and safe to install them, and two rooms where you would completely advise against placing them, justifying your criteria based on privacy risks, false triggers, or acoustics.
2. b) A family member claims: "The speaker does not record or send anything to the internet until we say the wake word out loud; before that, the microphone is inactive". Refute this statement with technical arguments, explaining how local passive listening (wake word engine) works and the risks of accidental activation.
3. c) Write three essential digital security rules and internal configuration settings that must be applied to the administrator account to prevent unwanted purchases, access to banking data, or indefinite storage of voice recordings.