Glossary
The words you will read on the roadmap, in one or two lines. When there is a 3D lab where you can see it, the link is there.
- Analog pin
- A pin that reads a voltage between 0 and 5 V and turns it into a number from 0 to 1023 on the Uno. Good for a potentiometer or a light sensor.
- Breadboard
- A board with holes connected inside to build circuits without soldering. Each column of 5 holes is joined.
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- Current (A, mA)
- How much electricity flows through the circuit. A red LED works at about 20 mA; an Arduino pin handles 40 mA at most.
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- Datasheet
- The maker’s document with a part’s limits: voltage, current, pins. If something doesn’t add up, the datasheet wins.
- Digital pin
- A pin with only two states: HIGH (5 V on the Uno) or LOW (0 V). It can light an LED or read a button.
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- ESC
- The driver for a drone’s motors. It gets the order from the flight controller and adjusts each motor’s speed.
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- Firmware
- The program that lives inside a board. When you upload your sketch, you are changing the microcontroller’s firmware.
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- GND (ground)
- The 0 V point the current returns to. Every part of a circuit must share the same ground.
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- H-bridge
- Four switches around a motor that let you reverse the current, and with it, the spin direction.
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- I2C
- A way to connect several sensors with just two data wires (SDA and SCL). Each sensor has its own address.
- IMU
- A sensor with an accelerometer and a gyroscope that measures tilt and rotation. The MPU-6050 is an IMU; drones use one to stay level.
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- LED
- A diode that gives light. It only lets current through one way: the long leg (+) goes toward positive. It always needs a resistor.
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- Microcontroller
- A tiny computer on a chip, like the Arduino Uno’s ATmega328P. It reads inputs, runs your program and controls outputs.
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- Motor driver
- A circuit that takes the microcontroller’s signal and gives the motor power from another source. Examples: TB6612FNG and L298N.
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- Ohm’s law
- V = I × R. With it you work out an LED’s resistor: (5 V − 2 V) / 0.02 A = 150 Ω, and you use the next value sold, such as 220 Ω.
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- Pull-up resistor
- A resistor that keeps a pin HIGH while the button is released, so it doesn’t read random values. The Uno has a built-in one: pinMode(pin, INPUT_PULLUP).
- PWM
- Switching a pin on and off very fast. The more time it spends HIGH, the brighter an LED or the faster a motor. On the Uno, analogWrite uses PWM.
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- Resistance (Ω)
- What holds the current back. A 220 Ω resistor protects an LED so too much current doesn’t flow.
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- Serial monitor
- A window where the board writes you messages over USB with Serial.println(). The speed (9600, for example) must match in the code and the monitor.
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- Servo
- A motor with gears and a potentiometer that tells it where it is. It gets a pulse and moves to that angle.
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- Short circuit
- When positive joins negative with nothing to limit the current. A huge current flows and something heats up or burns.
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- Sketch
- What an Arduino program is called. It has setup(), which runs once, and loop(), which repeats forever.
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- Ultrasonic sensor
- It measures distance with sound you can’t hear: it sends a pulse and times the echo. The most common is the HC-SR04.
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- Voltage (V)
- The push that makes current move. An AA battery gives 1.5 V and an Arduino Uno pin set HIGH gives 5 V.
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