Exercises: The Internet of Things

Explain what the Internet of Things (IoT) is and name three connected objects you know, stating what data or "sense" each one provides.

What does any given object, such as a lamp, need to become a connected object? Mention at least three elements and explain the role of each.

The figure shows how various household appliances are controlled from a smartphone, with one element in the chain marked with ?. Identify this element and explain the path followed by the command "turn on the light" from when you tap the screen until the light bulb turns on.

Name three connected objects in your home or neighbourhood and explain what "job" each one performs: measuring something, providing alerts, or automating something.

Explain what an IoT device control app is and what three functions it typically offers (viewing status, issuing commands, programming automated rules).

Explain the role played by a Wi-Fi router in a connected home and what happens to smart appliances in the house when the router is turned off or loses internet connection.

Explain what characterises a strong password and why leaving "123456" on an IP camera is a serious security issue.

Differentiate between Bluetooth and Wi-Fi as ways to connect a device: range, power consumption, and a typical device example for each.

A smart plug allows you to turn off a radiator from outside the home. Describe the complete chain the command follows (app, networks, plug) and reason what happens if the home Wi-Fi stops working.

Compare an infrared remote control with controlling a device over the internet: range, network requirement and privacy. Give an example where each option is clearly preferable.

A fitness tracker records your steps and sleep. Reason what sensors it uses, where this data is stored, and which app displays it. What risk to your privacy do you see in this operation?

A smart thermostat "learns" a family's schedule. Explain what data it needs to record to achieve this, what energy savings or comfort this learning provides, and what privacy risk it involves.

Explain what "the cloud" means in the context of the Internet of Things: where data is actually stored and what happens to devices if the manufacturer closes the service (real-world cases of devices becoming useless or "dumb").

A city installs sensors in parking spaces to indicate which ones are free. Describe the complete chain (sensor, communication network, platform, application) and two measurable benefits of the system.

Compare a device operating locally (all logic contained within the home) with one depending on "the cloud": response latency, privacy, and manufacturer reliance, giving an example of each type.

Devise a useful smart home rule and another that is a bad idea, both of the form "if [condition], then [action]". Justify each one considering false positives and what happens when the rule fails.

Design an IoT system that alerts a family on their smartphone if the moisture level of a houseplant drops too low: what sensor you would use, how it would connect, how the notification would arrive, and how the system would behave when there is no internet connection.

The owner of a tourist rental property installs a smart lock connected via Wi-Fi to the router and claims: "I'm not worried about security: the lock has a 16-character random password, so no one from the street can breach it". a) Refute their statement by identifying and justifying two real attack vectors against the lock that do not rely on guessing that password (for example, vulnerabilities in the manufacturer's firmware/cloud or attacks on the local Wi-Fi network). b) Design an improvement in the network and authentication architecture that increases the security of remote access without relying solely on the device's password.

A family is hesitating whether to install three home automation devices: a thermostat with a presence sensor, a robot vacuum cleaner with a navigation camera, and smart speakers in the bedrooms. They want to automate their home but demand that no data regarding private habits, floor plans, or voice recordings be stored on third-party servers. a) Analyze for each of the three devices what type of sensitive data it collects and justify whether it is technically feasible for it to operate 100% via local processing (Edge Computing) without connecting to the manufacturer's cloud. b) Establish a technical decision criterion to reject or accept any future connected device in their home, based on data architecture (local vs. cloud) and privacy policy.

In a smart classroom equipped with CO₂, temperature, and light sensors, the system controls motorized windows, climate control, and blinds. On a cold winter morning (5,0 °C outside), the classroom records 1400 ppm of CO₂ (stale air; recommended threshold: 800 ppm), the indoor temperature is 19,0 °C, and direct sunlight is blinding the digital whiteboard. a) Identify the two operational conflicts that arise when trying to simultaneously optimize student health, energy efficiency, and visibility. b) Design the control algorithm using conditional rules (IF... THEN...) that resolves both dilemmas, justifying which objective must have absolute priority in the event of a contradiction.

A school replaces 60 traditional light bulbs with low-cost "smart" bulbs (5,0 W of LED lighting and 1,5 W of continuous standby power consumption due to the Wi-Fi connection). Three years later, the manufacturer goes bankrupt, shuts down its cloud servers, and the mobile app stops working, preventing them from being turned on or dimmed remotely. a) Calculate the total energy (in kWh) consumed in standby by the 60 bulbs over those 3 years (1095 days) and compare it with the actual lighting consumption if they are turned on 5 hours a day for 180 school days per year. Interpret the result from the perspective of energy savings. b) Explain the "bricking" phenomenon these bulbs suffered and what technical design alternative (local open protocols versus cloud dependency) would have ensured they continued to work after the manufacturer closed down.

A manufacturer promotes a new smart speaker with the following claim: "To maximize your privacy, our device does not need a physical kill switch: it features smart software that digitally mutes the microphone, making it impenetrable to any cyberattack." a) From the perspective of hardware design and electronic security, refute the manufacturer's claim by comparing the security of a physical switch (which cuts power to the microphone) versus software or firmware muting. b) Explain technically the difference between the audio analysis performed by the low-power local chip to detect the wake word (hotword) and sending the command to the cloud, justifying why maintaining continuous transmission of all domestic audio would be unfeasible both technically and legally.

In an unsegmented home network, a smart light bulb and a low-cost IP camera share the same Wi-Fi with the personal computer used for online banking and storing backups. The camera uses outdated firmware that no longer receives patches from the manufacturer. a) Describe the concept of lateral movement (pivoting), explaining how an attacker who compromises the camera from the Internet could end up intercepting traffic or infecting the personal computer. b) Design a security scheme for this home network using the features of a modern router (segmentation via guest network/VLAN, traffic filtering rules, and isolation of unsupported devices). Justify how your design contains potential threats without preventing IoT devices from remaining useful.

A manufacturer of smart bathroom scales offers two versions of the same product: Model A costs €15,00 and requires creating a free account in its cloud mobile app to record weight, body fat, and heart rates; Model B costs €55,00 and stores data solely in the internal memory and on the user's local network (without external servers or subscriptions). a) Explain the hidden business model behind Model A: how the manufacturer monetizes the price difference at the expense of the user's biometric data, and what risks of commercial profiling or sharing with third parties (such as insurance companies) this entails. b) Technically justify why Model B is more resistant to planned obsolescence and guarantees the user's long-term digital sovereignty, despite its higher initial cost.

Topic challenge. Imagine you have to design an IoT robotic prototype to autonomously regulate the climate of a greenhouse in your town, optimizing consumption according to real-time weather.

1. Obtaining real data: Access the AEMET website, search for your municipality, and note the forecast maximum temperature ($T_{\max}$) for today (for example, $22,4\text{ \textdegree C}$).

2. Design and virtual construction: In Tinkercad Circuits, outline the structural design and circuit of a robot or automated hatch. Connect a temperature sensor ($TMP36$) and an actuator (servomotor or DC motor) for physical opening or ventilation to a controller board (Arduino or micro:bit).

3. Programming and IoT connection: Program the control so that, if the detected temperature exceeds the threshold of $T_{\max} - 2,0\text{ \textdegree C}$, the motor moves $90,0^\circ$. Add and document in the code the theoretical function that would periodically send these readings over Wi-Fi to an IoT server using the MQTT protocol.

4. Final product: Submit a brief report (one page) with the link or screenshot of the circuit in Tinkercad, the implemented code, and a technical justification of the chassis and IoT communication.

Assessment criteria:

• Coherent integration of AEMET data into the code conditions.

• Functional assembly of the circuit (board, sensor, and actuator) on the virtual platform.

• Clarity and technical rigor when justifying the robotic structure and the IoT data architecture.