Glossary

Not sure what a term means? Start here. Each entry gives you just enough to understand what you are looking at. For more depth, use the suggested prompt with any AI assistant (ChatGPT, Claude, Kimi, etc.).

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Hardware

Microcontroller A small chip that runs one program, repeatedly, on its own — no screen, no operating system, no multitasking. Think of it as a very simple machine that does exactly what you tell it and nothing else. Microcontrollers are inside everyday objects you already use: washing machines, car dashboards, traffic lights, electric kettles. The difference from a phone or laptop is that a microcontroller does one fixed job rather than running many apps.

💡 Ask AI: “Explain the difference between a microcontroller and a regular computer, using a simple real-world analogy.”

ESP32 The microcontroller chip inside the M5Stack StickS3. Made by a company called Espressif. It runs two processor cores at up to 240 MHz and includes built-in WiFi and Bluetooth — a combination that would have required several separate chips ten years ago. Because it is powerful, cheap, and widely used in consumer products, there is a large community and many ready-made code examples.

💡 Ask AI: “What makes the ESP32 popular for product prototyping?”

M5Stack StickS3 The physical device you are using. It packages an ESP32 chip together with a colour screen, two buttons, a battery, and a USB connector — all in a small case you can hold in one hand. “M5” stands for Modular, Microcontroller, Module, Mini. The “StickS3” name refers to its stick-like form factor and the S3 variant of the ESP32 chip inside.

Sensor A component that reads something from the physical world — temperature, motion, light, humidity, sound. Your code reads the sensor’s output value and decides what to do with it. Sensors are the “eyes and ears” of a device; without them a microcontroller can only respond to button presses.

Actuator A component that does something in the physical world — an LED lights up, a buzzer makes a sound, a motor turns, a valve opens. Most real products combine sensors and actuators: a sensor detects a condition and an actuator responds. For example, a smoke detector uses a smoke sensor (input) and a buzzer (output).

💡 Ask AI: “Give me five product examples that combine a sensor and an actuator.”

GPIO (General Purpose Input/Output) The electrical pins on a microcontroller that connect to external components. A GPIO pin can either read a signal coming in (input mode) or send a signal going out (output mode). UIFlow labels them with port names like Port A or Port B, so you do not need to remember the physical pin numbers. Think of GPIO pins as sockets — you plug in whatever sensor or actuator you need.

💡 Ask AI: “Explain GPIO pins using a non-technical analogy.”

Firmware The software stored permanently on the microcontroller’s internal memory. Unlike an app on a phone, firmware runs directly on the hardware — there is no operating system in between. UIFlow 2.0 is itself firmware; the blocks you write are converted to MicroPython and uploaded on top of it. “Flashing” means replacing the firmware with a new version, which is what you do when you first set up the device or upgrade UIFlow.

💡 Ask AI: “What does it mean to flash firmware, and why might it go wrong?”

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Programming

Block programming Writing code by dragging and connecting visual blocks, similar to building with interlocking tiles. Each block represents one instruction; connecting them in sequence defines what happens and in what order. Block programming removes the need to remember syntax (punctuation and spelling rules of a programming language), which lets you focus on the logic of what you want the device to do.

MicroPython A lightweight version of the Python programming language designed specifically for microcontrollers. It works on devices with as little as 256 KB of memory — far less than a regular Python installation needs. When you build a program in UIFlow, it converts your blocks into MicroPython behind the scenes. You can switch to the code view inside UIFlow to see exactly what was generated, which is a useful way to start learning text-based programming.

💡 Ask AI: “Show me a simple MicroPython example that reads a button and turns on an LED.”

Serial / COM port The communication channel between your laptop and the StickS3 via USB. Your laptop treats it as a virtual serial port — on Windows it appears as COM3, COM4, etc.; on Mac/Linux as /dev/tty.usbserial-.... This is how UIFlow sends your code to the device and how the device can send debug messages back to your laptop. If UIFlow cannot connect, the COM port is usually the first thing to check.

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Networking & IoT

IoT (Internet of Things) Physical devices — sensors, machines, appliances — that are connected to the internet or to each other, sending and receiving data. The “things” range from smart home bulbs to industrial factory monitors. Your StickS3 becomes an IoT device the moment it connects to WiFi and shares data with a server or another device. The scale of IoT is large: estimates put the number of connected devices at over 15 billion worldwide.

💡 Ask AI: “Give me five real IoT product examples and describe what data each one collects and sends.”

WiFi Wireless connection to a local network and the internet using radio signals. The ESP32 chip has WiFi built in, so the StickS3 can join any standard 2.4 GHz network without extra hardware. During weeks 1–2 you use a USB cable to connect directly; later you may connect via WiFi to send data to a server, receive remote commands, or display readings on an online dashboard.

IP address A number that identifies a device on a network — like a postal address for data packets. Every device on a WiFi network has one assigned by the router (for example, 192.168.1.42). When your StickS3 sends sensor data to a server, the server needs to know its IP address to reply. IP addresses can be fixed (“static”) or change each time a device connects (“dynamic”).

MQTT A messaging protocol designed for small devices on unreliable connections. Instead of devices talking directly to each other, they all connect to a central server called a broker. Devices publish data to a named topic (e.g. sensors/temperature); other devices or dashboards subscribe to that topic and receive the data automatically. This means a sensor and a dashboard never need to know each other’s IP address — only the broker’s address matters. Very common in IoT dashboards and smart-home systems.

💡 Ask AI: “Explain MQTT publish/subscribe with a coffee shop analogy.”

HTTP / REST API HTTP is the same protocol your browser uses to load websites. A REST API is a structured way to send and receive data over HTTP — using standard actions like GET (fetch data) and POST (send data). An IoT device can POST sensor readings to a web server, or a phone app can GET the latest readings from a device. Most cloud IoT platforms (including Adafruit IO and Tencent Cloud IoT) accept data over HTTP, which makes it easy to get started without learning a new protocol.

💡 Ask AI: “What is a REST API and how would a sensor device use one to send data to a server?”

Cloud Servers hosted on the internet — not on your device or in the building. IoT products often send data to the cloud for storage, analysis, remote access, and sharing across devices. Examples relevant to this course: AWS IoT, Tencent Cloud, Adafruit IO, ThingSpeak. The advantage of the cloud is that anyone with the right credentials can access the data from anywhere; the trade-off is that an internet connection is required.

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Still unclear?

These definitions are intentionally brief. If a term still does not make sense after reading:

1. Use the suggested AI prompt above with your preferred AI tool
2. Ask in the session — there are no bad questions
3. Search the M5Stack Community Forum for real examples