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LED - Red (5mm)

LED

Standard 5 mm indicator LED. Always use it with a series resistor.

Specifications

Colour

Red

Diameter

5 mm

Forward voltage

2.0-2.2V

Forward current

20 mA (max. 30 mA)

Shop prices

• RobotzadePack of 10 · In stock6.00 ₺
• Direnc.netIn stock0.73 ₺
• MotorobitPack of 10 · In stock7.57 ₺
• HatfonIn stock0.76 ₺
• RobotistanPack of 10 · In stock8.50 ₺
• Robo90Pack of 10 · In stock8.93 ₺
• KomponentciPack of 10 · In stock10.48 ₺
• RobocomboIn stock1.50 ₺
• ElektrovadiIn stock1.80 ₺
• HobiDevreIn stock1.92 ₺
• Modül ElektronikIn stock1.99 ₺
• RobotsepetiIn stock2.44 ₺
• Entegre DünyasıIn stock3.58 ₺
• SAMM MarketIn stock5.95 ₺
• Robolink MarketPack of 10 · Out of stock13.50 ₺
• F1 DepoPack of 10 · Out of stock15.00 ₺

Prices read from the shops' pages on 22 October 2026. Prices and stock may have changed since; check at the shop before you buy.

Projects with this part

• LED BlinkBeginner10 minYour first project: it blinks an LED on the Arduino's pin 13 once a second and writes each change to the Serial Monitor. It teaches you to use a breadboard, an LED and a resistor. The board's own L light is also on pin 13, so it blinks along with the LED. No extra library needed.Open project
• Night Light (LDR)Beginner20 minA night light that turns itself on as the room gets dark. An LDR (light sensor) and a 100 kΩ resistor form a voltage divider; the Arduino reads the light level on pin A0 and, in the dark, dims the LED on pin 9 with PWM. It teaches analog reading, thresholds and PWM. No extra library needed.Open project
• Traffic LightBeginner20 minA real traffic light with three LEDs: red, red + yellow, green and yellow light up in the order used in Turkey, and each stage is also written to the Serial Monitor. It teaches driving several outputs in turn, timing with digitalWrite and delay, and gathering a repeated job into its own function. You can change how long each light stays on with the constants in the code. No extra library needed.Open project
• Toggle an LED with a ButtonBeginner20 minTurn a red LED on and off with a button: every press flips the LED, and the press count and the LED's state are written to the Serial Monitor. It teaches reading a button with digitalRead, the Arduino's built-in pull-up resistor (INPUT_PULLUP), catching the moment a button is pressed and waiting out contact bounce (debounce). The button needs no extra resistor, and no extra library is needed.Open project
• LED Brightness with a PotentiometerBeginner20 minSet an LED's brightness by turning a potentiometer's knob: with the knob at one end the LED is off, and it gets brighter as you turn towards the other end. The value read and the brightness given to the LED are also written to the Serial Monitor. It teaches reading an analog input with analogRead, turning one range into another with map, and using PWM with analogWrite. No extra library needed.Open project
• Parking SensorIntermediate45 minLike the parking sensor in a car: the HC-SR04 measures the distance to whatever is in front of it, the buzzer starts beeping once something comes within 1 metre and the beeps get faster as it comes closer; below 10 cm the tone is steady. Green, yellow and red LEDs show the far, middle and near zones, and the distance is written to the Serial Monitor. It teaches timing with millis() instead of delay, so measuring, beeping and the lights run without waiting for each other, writing a function that returns a value, splitting into zones with if / else if, and turning the distance into a beep gap with map. No extra library needed.Open project
• Motion AlarmBeginner25 minA small home alarm that goes off when someone walks in: the HC-SR501 PIR sensor senses the change in the heat a human body gives off, the buzzer plays a two-tone siren and the red LED blinks; every alarm is counted in the Serial Monitor. It teaches reading a sensor's digital output, catching only the moment motion starts, sounding for a set time with millis(), and gathering the job into its own function. No extra library needed.Open project
• Smoke and Gas AlarmIntermediate35 minAn alarm that goes off when smoke or a flammable gas (LPG, natural gas, methane) shows up in the kitchen or a room: the MQ-2 sensor's analog output is read, the clean air value is measured at start-up, and once the reading rises well above it the buzzer plays the three-beep pattern (T3) that real smoke alarms use while the red LED flashes with the beeps. The green LED blinks while warming up and stays on once the alarm is armed. It teaches reading an analog sensor against its own clean air value, using two separate thresholds so the alarm does not flicker at the edge, and playing a sound pattern with millis() while still taking readings. No extra library needed. This is a learning project; it does not replace a certified smoke and gas alarm at home.Open project
• RFID Card Door LockIntermediate60 minA door lock that opens with a card or key fob you have introduced: the RC522 reader reads the card's number, and if it is known the green LED lights up, a short beep sounds and the servo turns the latch and opens the door for 5 seconds; an unknown card lights the red LED and sounds a long beep. The first card you scan becomes the master card: scanning it opens adding mode for 10 seconds, and a new card scanned meanwhile is added, a known one removed. The cards are kept in the Arduino's EEPROM memory, so they are not forgotten when the power goes. It teaches talking to a module over SPI, comparing card numbers, keeping a small list in EEPROM, and letting a mode close by itself. Install "MFRC522" from the Library Manager; Servo and EEPROM come with the Arduino IDE. This is a learning project; do not use it as a real door's only lock.Open project
• Flame-Sensing Fire AlarmBeginner30 minA fire alarm that recognises a flame by the infrared light it gives off: when the flame sensor sees a lighter or a candle flame, the buzzer plays a rising siren and the red and blue LEDs flash in turn like a fire engine's lights. While idle, the blue LED blinks briefly every 2 seconds to show the alarm is on watch. The alarm does not sound until a flame has lasted half a second, so a single spark or glint does not set it off, and it keeps sounding for 3 seconds after the flame is out. It teaches smoothing the on-and-off digital signal of a flickering flame, filtering out short flashes with a time condition, and playing a siren with millis() while reading the sensor. No extra library is needed. This is a learning project; it does not replace an approved smoke detector at home.Open project
• Air Quality IndicatorBeginner30 minAn indicator that shows a room's air like a traffic light: the MQ-135 sensor reacts to pollutants such as smoke, ammonia, benzene and the CO₂ that builds up from breathing; green lights while the air is clean, yellow as it starts to get stale and red when it is bad, and the Serial Monitor tells you to air the room. At start the sensor warms up and the clean-air value is measured; every reading after that is judged against it, and if the air gets even cleaner the value is updated. It teaches reading an analog sensor against its own clean-air value, reducing jitter by averaging several readings and leaving a margin at the thresholds so the LEDs do not flicker at the edge. No extra library is needed. The MQ-135 does not tell gases apart and does not give a calibrated CO₂ reading; it shows roughly how polluted the air is.Open project
• Arduino-Free Dark-Activated LampBeginner25 minA night light with no Arduino and no code, built from just a 9V battery, a BC547 transistor, an LDR and a potentiometer: when it gets dark the LED lights by itself, and it goes out when the light comes back. With the potentiometer you set how dark it must be. It teaches three cornerstones of basic electronics: the voltage divider (the potentiometer and the LDR), the transistor as a switch that turns a large current on and off with a small base current, and limiting an LED's current with a resistor. You see how these parts, used in Arduino projects all the time, work without one.Open project
• LED Control from Your Phone (ESP32 Wi-Fi)Beginner20 minThe ESP32 joins your home Wi-Fi and serves a small web page; with the ON and OFF buttons on the page you open in your phone's browser, you switch the LED from afar. No app to install: any phone or computer on the same network can open the page. The first step of smart-home projects: a relay, a motor or any other device is controlled the same way.Open project