Engineering · Arduino · Projects
Arduino Project Library
Pick a project, watch it run, then change it.
Every project opens in the Arduino Simulator with the circuit already built. See every wire, read the explanation, press Run, and then change the steps to make it your own. Over time more projects are added here.
LEDs and lights 39
16-LED Running LightOne light runs along sixteen LEDs and starts again at the beginning.Medium4-LED Binary CounterFour LEDs count from 0 to 15 in binary. LED 1 is the smallest bit.MediumAlternate Flasher (Police Style)The left four LEDs and the right four LEDs flash one after the other.EasyBinary Counter with a VariableOne variable counts from 0 to 15 and four LEDs show it in binary.MediumBluetooth RGB Colour LampThe phone chooses red (1), green (3), blue (5) or white (7). Any OFF button switches the lamp off.EasyBluetooth Ring LampThe ON buttons light 2, 4, 6 or 8 pixels of the ring. Any OFF button turns it off.EasyButton Brightness Steps (Off, Low, Medium, High)Each press makes the lamp brighter in four steps and then back to off.MediumCoin Flip with Two LEDsPress to flip: red LED for heads, green LED for tails.EasyColour Detector with LEDsHold a red, green or blue card near the sensor and the matching LED lights up.MediumIR Obstacle Sensor with LEDsRed lights when something is in front of the sensor, green when the way is clear.BeginnerIR Remote Brightness RingKeys 1 to 8 light that many pixels. Key 0 clears the ring.EasyIR Remote RGB Mood LampKeys 1 to 7 choose seven colours and key 0 switches the lamp off.EasyJoystick Direction ColoursLeft shows red, right blue, down green and up magenta.MediumKeypad Colour PickerKeys 1 to 7 choose seven colours on the RGB LED and key 0 switches it off.EasyKnight Rider Light (8 LEDs)A single light sweeps left and right across eight LEDs, like the car in an old TV show.MediumKnob Chooses the RGB ColourTurn the knob to move through seven colours.EasyKnob Fades Two LEDs in Opposite WaysTurn the knob and the red LED gets brighter while the green one gets dimmer, like a mixing desk.EasyKnob LED Level MeterTurn the knob and more LEDs light, like the level meter on an audio amplifier.EasyKnob Level RingTurn the knob to fill the ring, like a volume indicator.EasyLED Chaser LightA light runs along a row of five LEDs and bounces back, like the scanner on a toy car.BeginnerLED Chaser with Speed KnobThree LEDs run in a row. The knob is on the board, ready for you to make the speed adjustable.MediumLED Dimmer with a KnobTurn the knob to make an LED brighter or dimmer.EasyLED Fade In and Out (Breathing Light)An LED slowly glows brighter, then dimmer, like a sleeping computer light.EasyLED Flasher LightTwo LEDs flash one after the other like an emergency light bar.BeginnerLamp That Remembers On or OffA push-button toggles a lamp. After a power cut the lamp comes back in the state it had before, like a real smart switch.EasyLucky Draw: One of Four LEDsPress the button and a random LED lights up to pick the winner.MediumNeoPixel Ring Fill-Up AnimationThe colour pixels on a ring light up one by one until the whole ring is lit, then it clears.BeginnerNight Path Light (PIR + Ring)The ring lights fully when somebody passes in the dark.MediumPedestrian Crossing with BeeperCars have green. When a pedestrian presses the button, cars get red, pedestrians get green and the beeper helps blind users.MediumPolice Siren Light and SoundRed and blue-white lights alternate with a two-tone siren.EasyPress-to-Brighten Lamp (Force Sensor)The harder you press the force pad, the brighter the LED glows.EasyRGB LED Colour CycleAn RGB LED steps through red, yellow, green, cyan, blue, magenta and white.BeginnerRGB LED Colour PickerThree buttons choose red, green or blue on an RGB LED.EasyRandom Blinking Candle LightAn LED flickers with random brightness like a candle.EasySOS Signal LightThe light and buzzer send three short, three long and three short signals: SOS in Morse code.EasyStep the Light with a ButtonEach press moves the single lit LED one place along the row.EasyTraffic Light with Night ModeIn daylight the green light is on. At night the yellow light blinks, like on a quiet road.MediumTraffic Light with Pedestrian ButtonCars get a green light until a pedestrian presses the button, then yellow, then red while people cross.EasyTwo-Way Traffic ControlA junction where road A and road B take turns, with red, yellow and green lights for each.Medium
Buttons and switches 21
433 MHz Remote: Four LEDsA key fob with four keys lights four LEDs, one for each key.Easy433 MHz Transmitter with Two ButtonsTwo buttons send key A and key B by radio. The green LED shows that a key was pressed.MediumBluetooth Phone LED ControlUse three ON/OFF button pairs in a phone app to switch three LEDs.EasyDoor Bell with Message and ChimeA visitor presses the bell. The LCD changes, the LED lights and a two-note chime plays.EasyDoor Bell with Push ButtonPress the button and the buzzer plays a two-note "ding-dong".BeginnerIR Remote LED ControlPress 1, 2 or 3 on the remote to light the matching LED. Let go and it switches off.BeginnerKeypad LED SelectorPress 1, 2 or 3 on the keypad to light the red, yellow or green LED while the key is held.BeginnerKeypad Lamp SwitchKey A switches the lamp relay on, key B switches it off.EasyLED Pong for Two PlayersA light runs along five LEDs like a ball. Player 2 must press when the ball is on the far red LED. Player 1 must press when it comes back to the first red LED. A good hit gives you the point; a miss gives it to the other player.HardLoRa Remote Switch (Relay)A pump a long way from you is switched on by key A and off by key B over a LoRa radio.HardPush Button Controls an LEDThe LED lights up only while you hold the button down.BeginnerQuick Draw: Who Presses First?After a short beep the first player to press wins. Player 1 gets the green LED and player 2 gets the red LED.EasyQuiz Buzzer for Two PlayersPress button 1 to light the red LED and buzz. This is the first half of a two-player quiz. Add the second player yourself.EasyRadio Remote Lamp (Relay)Key A switches a lamp on, key B switches it off, like a remote gate or fan.MediumSimon Memory Game (Two Buttons)Watch the pattern: green, red, green. Then repeat it with the buttons (button 1 is green, button 2 is red). A right answer lights green, a wrong one sounds the buzzer.HardSlide Switch and LEDA slide switch keeps the LED on or off, like a real lamp switch.BeginnerThree Buttons, Three LEDsEach button controls its own LED. Press two buttons and two LEDs light.EasyTwo Lamps, One Slide SwitchThe slide switch picks which of two lamps is on: green or red.BeginnerTwo-Button LED Dimmer StepsButton 1 switches the light bar on, button 2 switches it off. A small step towards a real dimmer.EasynRF24 Radio Remote: Four LEDsAn nRF24L01 radio receives key numbers and lights four LEDs.MediumnRF24 Transmitter with Two ButtonsTwo buttons send key 1 and key 2 over an nRF24 radio.Medium
Light sensing 18
Auto-Brightness Night LightThe darker the room, the brighter the lamp glows, and it fades out in daylight.EasyAutomatic Night LampA light sensor switches a lamp on when it gets dark and off in daylight.EasyAutomatic Street LightThree street lamps switch on together at dusk and off at dawn.EasyCloud Light Logger (Lux)A lux sensor logs how bright a room is through the day.MediumDark-Activated LED BarAs the room gets darker, more LEDs switch on, one more at each level.EasyLamp On at Night and in Low LightThe lamp only works in the evening and only when the room is dim.MediumLight Direction IndicatorThree LEDs show whether the light comes from the left, the right, or straight ahead.EasyLight Keeper with a Set-Point KnobTurn the knob to set the brightness you want in a room; the lamp switches on when the room is darker than that.MediumLight Level Meter (LDR + 16 LEDs)Brighter light makes more LEDs shine.EasyLight Level RingThe ring shows how bright the room is. Cover the sensor and the ring goes dark.EasyLight Level on a DigitThe digit shows how bright it is, from 0 (dark) to 9 (bright).EasyLight Meter on the LCDThe LCD shows how bright it is, from 0 to 100 percent.EasyLux Meter with LCDReads the real brightness in lux and shows it on the LCD.EasyOLED Light MeterThe brightness in percent is shown on the OLED.EasySD Card Light LoggerThe brightness of a room is saved to an SD card every 5 seconds.MediumSmart Lamp: Lux Sets the Lamp BrightnessThe lamp gets brighter as the room gets darker, keeping the light steady.MediumSmart Street Light (Dim and Boost)At night the lamp glows at 20 percent to save energy. When someone walks by, it rises to 100 percent. In daylight it is off.MediumStudy Desk Light CheckerRed if the light is too dim for reading, green if it is bright enough.Easy
Motion and security 12
Anti-Theft Alarm with Arming SwitchSwitch the alarm ON and the PIR sensor guards the room. Movement sounds the buzzer and lights the red LED. With the switch OFF nothing happens.EasyBox Guard: Tilt or Touch AlarmThe alarm sounds if the box is tilted or touched.EasyDoor Open Alarm with Reed SwitchA magnet on the door keeps the reed switch closed. Open the door and the alarm sounds.EasyHand Swipe Direction DetectorTwo IR sensors side by side see which one your hand crosses first. A green LED means swipe right, a yellow LED means swipe left.MediumIntruder Alert with PIR SensorWhen the PIR sees movement, a red light comes on and the buzzer beeps twice.EasyMotion Light That Works Only in the DarkThe light comes on when someone moves, but only if the room is dark.MediumMotion Smiley on LED MatrixWhen someone moves in front of the sensor a smiley greets them; otherwise the matrix is blank.EasyPIR Motion with Two LEDsRed when motion is detected, green when everything is quiet.BeginnerStaircase Lighting with PIRStair lights come on step by step when someone arrives and switch off after a few seconds.EasyTilt AlarmIf someone tilts or lifts the box, the alarm goes off.BeginnerTwo-Layer Door Alarm (Reed + PIR)The PIR gives a yellow warning for movement. If the door magnet is lifted the red LED and buzzer fire.MediumWelcome Message When Someone ArrivesA recorded welcome (track 2) plays when the PIR sensor sees someone.Easy
Distance and parking 23
Car Parking AssistantThe LCD shows how far the wall is. Green means safe, red and a beep mean stop.MediumDistance AlarmThe alarm sounds when something comes closer than 20 cm.EasyDistance Bar Graph with LEDsThe closer an object is, the more LEDs light up, like a parking sensor bar.EasyDistance Colour IndicatorThe RGB LED shows red when close, green when medium, blue when far and white when very far.EasyDistance Digit MeterThe digit shows how far an object is, in steps of 10 cm.EasyDistance Digit with Close AlarmThe digit shows distance in tens of centimetres and the buzzer sounds under 15 cm.MediumDistance Meter with LCDAn ultrasonic sensor measures the distance and shows it on a 16x2 LCD.EasyGPS Location on LCDShows the latitude and longitude from a GPS module on the LCD.MediumMini Radar SweepA distance sensor on a servo sweeps left and right. The red LED lights when something is closer than 30 cm.MediumOLED Distance MeterThe distance in centimetres from an ultrasonic sensor is shown on the OLED.EasyParking Distance Bar (16 LEDs)The closer you are to the wall, the more LEDs light up. Very close, the buzzer sounds.MediumParking Distance RingThe ring fills as a car gets closer. Under 15 cm the buzzer sounds.MediumParking Gate Car CounterTwo IR sensors at the car park gate count cars in and out. The red LED shows that the car park is full (more than 5 cars).HardParking Sensor Arrow on LED MatrixAn arrow shows that you may move forward. Close to the wall the matrix lights up fully and a buzzer sounds.MediumRadar with Angle and Distance on LCDThe LCD shows the scanner angle and the distance it measures at that angle.HardSmart Parking: Four Slots with LEDsEach parking slot has an IR sensor and a red LED. The green LED shows that the car park is FULL.MediumSmart Stick for the Blind (Distance Beeps)An ultrasonic sensor on a stick beeps in a higher tone as an obstacle gets closer.MediumSmart Traffic Junction (Queue Priority)Road A normally has green. When a car waits on road B and none waits on road A, road B gets the green. A car on road A always takes priority.HardSpeed Trap with Two IR GatesA vehicle passes two IR gates one metre apart. The Arduino measures the time between them and shows the speed. A buzzer sounds above 40 km/h.HardToll Barrier with Distance DisplayThe barrier lifts when a vehicle is closer than 25 cm, and the LCD shows how far the vehicle is.MediumUltrasonic Radar ScannerA servo turns an ultrasonic sensor around like a radar. Objects appear as green dots on the radar screen.MediumUltrasonic Servo GateThe gate arm lifts when an object comes within 20 cm and drops when it goes away.EasyUltrasonic Switch with RelayWave your hand near the sensor and the relay switches on.Easy
Motors and movement 52
Bluetooth Car: Forward, Back and StopThe phone buttons F, B and S drive the motor forward, backward or stop.MediumBluetooth Fan Speed StepsPhone buttons choose low, medium or high speed, and stop.MediumBluetooth Remote Control CarDrive the car from a phone app: forward, back, left, right and stop.MediumCar with IR Obstacle SensorA simple IR obstacle sensor makes the car turn when something is very close.EasyColour Sorter with ServoThe servo arm points to a different tray for each colour: red, green and blue.MediumDC Fan Speed ControllerTurn a knob to change the speed of a small DC motor or fan.EasyDual Axis Solar TrackerFour light sensors and two servos turn a panel left and right and up and down towards the sun.HardFire Fighting Robot CarThe robot drives forward. When its flame sensor sees a fire it stops, switches on the water pump and sounds the buzzer.MediumFlex Sensor Controls a ServoBend the flex sensor and the servo follows, like a robot finger.EasyFollow-Me Robot CarThe car follows an object in front of it. It drives forward when the object is further than 25 cm, stops when it is near, and also stops if it is lost (more than 80 cm).MediumIR Remote Car ControlVOL+ drives forward, VOL- drives backward and PLAY stops.MediumIR Remote Control CarA TV-style remote drives the car: 2 forward, 8 back, 4 left, 6 right, PLAY to stop.MediumIR Remote Fan Speed ControlKeys 1, 2 and 3 select low, medium and high speed. Key 0 stops the motor.MediumIR Remote Servo ControlKeys 1 to 4 on the remote move the servo to four fixed angles.EasyJoystick Controlled CarPush the joystick forward, back, left or right to drive the car.MediumJoystick Controls Two ServosLeft-right and up-down on the joystick move two servos, like a pan-tilt camera.MediumJoystick Controls a DC MotorPush the joystick up for forward, down for reverse. The middle position stops the motor.MediumKeypad Controlled CarKeys 2, 8, 4, 6 and 5 on the keypad drive the car like the arrow keys of a game controller.MediumKeypad Motor Speed SelectorKeys 1, 2, 3 set speed, key 4 reverses and key 0 stops.MediumKeypad Servo PositionsKeys 1 to 5 move the servo arm to 0, 45, 90, 135 and 180 degrees.EasyKeypad Stepper PositionsKeys turn the stepper by 90 or 180 degrees in either direction.MediumKnob Servo with Angle DisplayThe knob sets the servo angle and the LCD shows the knob value.EasyKnob Speed and DirectionTurn the knob left for reverse, middle for stop, right for forward.MediumLight Avoiding Robot Car (Shadow Seeker)The car steers away from bright light and looks for shade.MediumLight Following Robot CarA car with two light sensors at the front drives towards a torch and steers to the brighter side.MediumLight-Following ServoThe servo arm turns more as the light gets brighter.EasyLine Follower RobotThe car follows a black line on the floor using two IR line sensors.MediumLine Follower that Stops for ObstaclesThe line follower stops if something comes closer than 20 cm in front.MediumMotion Fan (DC Motor)A small DC fan runs while somebody is near.EasyMotor Direction Control with L298NHold button 1 to drive forward and button 2 to reverse, like a toy car.MediumMotor Speed Ramp UpThe motor speeds up in steps of 10 percent and then starts again slowly.MediumMotor Start/Stop StationPress START to run the motor and STOP to stop it, with a green running light.EasyObstacle Avoiding CarThe car drives forward and spins away when a wall or box is closer than 40 cm.MediumObstacle Car: Back Up, Then TurnThe car stops, beeps, backs up a little and turns before going on.MediumPan-Tilt Camera with Keypad PresetsKeys 1 to 9 point a camera mount at nine directions: the keypad is like a 3 by 3 grid.MediumParking Gate Opens When a Slot Is FreeThe gate stays closed when all four slots are full and opens when at least one is free.MediumPhone-Controlled ServoF, B, L and R move the servo to four angles. Stop returns to centre.EasyRadio Remote Gate with ServoKey A opens a model gate (servo to 90 degrees) and key B closes it.MediumRailway Crossing GateWhen a train comes closer than 60 cm the gate lowers, the red light shows and the bell sounds.MediumRobot Arm Poses with KeypadKeys 1 to 4 move a three-servo arm to named poses: Home, Reach, Grip and Drop.HardRobot Car Drives a SquareThe car drives forward, spins right, and repeats to trace a square on the floor.EasyRobot Gripper with a ButtonHold the button and the gripper closes. Let go and it opens.EasyServo Motor SweepA servo arm moves to 0, 90 and 180 degrees and back.BeginnerSmooth Servo Sweep with a VariableThe servo turns in small steps from 0 to 180 degrees and starts again.MediumSolar Tracker (Single Axis)Two light sensors on the left and right of a panel make a servo turn the panel towards the brighter side.MediumStepper Button ControlButton 1 turns the stepper 90 degrees one way, button 2 turns it 90 degrees back.MediumStepper Motor DemoA 28BYJ-48 stepper turns one full turn forward and one back.MediumTachometer (IR Sensor and LCD)An IR sensor sees a mark on a spinning shaft once per turn. The time between marks gives the speed in revolutions per minute.HardThree-Servo Arm: Base, Shoulder, GripperThree knobs control a robot arm: base turn, shoulder lift and gripper opening.HardTwo-Joint Robot Arm with KnobsTwo knobs move the two joints of a small robot arm: the base and the elbow.MediumTwo-Mode Robot: Auto or Phone ControlA switch chooses the mode. With the switch OFF you drive the car from your phone. With it ON the car drives itself and spins away from obstacles.HardnRF24 Remote Control CarFour keys on a radio remote drive the car: A forward, B backward, C spin left, D spin right.Hard
Temperature and climate 27
Barometer and Weather HintShows air pressure. The yellow LED warns that low pressure may mean rain is coming.MediumCloud Temperature Logger (Wi-Fi)The Arduino reads the temperature and sends it to a ThingSpeak graph on the internet.MediumCloud Weather StationShows temperature and humidity on the LCD and sends the temperature to the cloud.HardComfort IndicatorGreen means comfortable. Red means too hot or too humid.MediumDHT11 Temperature and Humidity MonitorA DHT11 sensor shows temperature and humidity on an LCD, with a hot warning light.EasyDS18B20 Digital ThermometerA waterproof digital temperature sensor shows its reading on an LCD.EasyDigital Thermometer with LM35 and LCDAn LM35 sensor measures the temperature and the LCD shows it.EasyDual Axis Solar Tracker with Weather LCDA two-axis solar tracker that also shows the air temperature and humidity on an LCD.HardHeater ThermostatThe heater switches on below 20 degrees and off above 24 degrees.MediumHigh Temperature SMS AlertAn SMS is sent when the temperature rises above 45 degrees C, for example in a cold room or a server cupboard.MediumHotter Room Indicator (Two Sensors)Two temperature sensors compare two rooms. The red LED shows room 1 is warmer; the blue LED shows room 2 is warmer.EasyHumidity Controlled FanAn exhaust fan starts when the humidity goes above 70 percent, like in a bathroom.MediumNon-Contact Thermometer with LCDPoint the sensor at an object to read its temperature without touching it. The red LED lights above 38 degrees C.MediumOLED ThermometerThe temperature is shown in big digits on a small OLED screen.EasyOven Temperature Monitor (Thermocouple)A K-type thermocouple reads high temperatures and the buzzer sounds when the oven passes 250 degrees C.MediumRain AnnouncementWhen rain is detected a recorded message (track 4) says to bring the washing in.EasySD Card Temperature LoggerThe temperature is saved on an SD card every 5 seconds as a text file you can open in Excel.MediumServo Temperature GaugeA servo needle shows the temperature on a dial, 0 to 50 degrees.EasyTemperature Bar MeterThe hotter it gets, the more LEDs light up.EasyTemperature Ring GaugeThe warmer it gets, the more pixels light up, from 20 to 40 degrees C.EasyTemperature-Based Fan ControlThe hotter it gets, the faster the fan spins. A red LED warns when it is above 40 degrees.MediumThermistor Fan ControllerThe fan runs when the thermistor gets hotter than 30 degrees C.MediumThermistor Thermometer with LCDA cheap thermistor shows the temperature on the LCD.EasyThermostat with LCD and FanThe LCD shows the temperature. Above 30 degrees the fan relay and the red LED switch on.MediumThermostat with a Set-Point KnobTurn the knob to choose a temperature; the fan runs while the room is warmer than the set point.MediumThree-Level Temperature IndicatorGreen below 30 degrees, yellow from 30 to 40, red above 40.EasyWeather Station: Heat, Humidity, Rain, LightA small weather station shows temperature, humidity, rain wetness and light on the LCD.Hard
Water and plants 30
Agricultural Spray RobotThe robot rolls along a crop row. When the soil probe finds dry soil (below 30 percent) it stops and its pump sprays water.MediumAutomatic Bottle Filling StationWhen a bottle is placed under the tap a pump fills it for 3 seconds. The next bottle can start only after the first is removed.MediumAutomatic Plant Watering SystemWhen the soil is dry the pump relay switches on until the soil is wet again.MediumCloud Soil Moisture MonitorYour plant sends its soil moisture to the internet and a red LED warns when it is dry.MediumCloud Water Tank LevelThe water level is shown on an LCD and sent to the cloud so you can check the tank from anywhere.MediumCloud pH MonitorLogs the pH of a pond or aquarium to the cloud.HardLoRa River Flood Level AlertA level sensor sends a warning (key 1) at 70 percent and a danger (key 2) at 90 percent.HardPlant Monitor: Soil, Light and TemperatureThree sensors tell you how your plant is doing. A red LED warns when the soil is dry.MediumRain Detector AlertWhen rain falls on the plate, a servo closes the window and a buzzer warns you.EasyRain Intensity RingThe wetter the sensor, the more pixels light.EasyRain Monitor with MessageThe LCD shows how wet the sensor is and a light comes on when it rains.EasyRain Sensor Window CloserWhen rain is detected the servo closes the window and a light comes on.EasySD Card Soil Moisture LoggerSoil moisture is saved on an SD card and a blue LED warns when it is dry.MediumSoil Moisture IndicatorRed means dry, yellow means damp, green means wet: a simple plant helper.EasySoil Moisture RingA ring shows how wet the soil of a plant is.EasySoil Moisture on a DigitA single digit shows soil wetness from 0 (dry) to 9 (wet).EasyTDS Water Quality MeterShows how much dissolved salt and mineral is in the water and beeps if it is above 500 ppm.EasyTFT Soil Moisture GaugeThe TFT shows the soil moisture with a coloured bar. A blue LED says that the plant needs water.MediumTank Filler with Ultrasonic LevelThe sensor looks down into a tank. The pump runs when the water is far (above 40 cm) and stops when it is near (below 10 cm).MediumTimed Plant Watering with RTCA pump runs for one hour each morning (7 am) to water the plants.MediumTwo Tank Level BalancerA pump moves water from tank 1 to tank 2 while tank 1 is much fuller.MediumWater Clarity Indicator (Turbidity)Green for clear water, yellow for a little cloudy, red for muddy.EasyWater Level Monitor with LCDThe LCD shows the tank level and the buzzer warns when it is almost empty.EasyWater Quality Station: pH and TDSOne LCD shows both pH and TDS. The red LED warns if either is outside the good range.MediumWater Tank Level AlarmThe alarm sounds when the tank is nearly full; green means there is still room.EasyWater Tank Level BarSixteen LEDs show how full the tank is. A red LED warns when it is nearly empty.MediumWater Tank Low SMSSends an SMS when the tank level falls below 20 percent.MediumWater Tank Pump ControllerThe pump starts when the tank is nearly empty (below 25 percent) and stops when it is nearly full (above 90 percent).MediumWater Test Kit: pH, TDS and TurbidityA small water-testing kit: three sensors and one red warning light.HardpH Water Monitor with LCD and Warning LEDsShows the pH of the water. Green means safe (6.5 to 8.5), red means too acid or too alkaline.Medium
Fire, gas and safety 35
Alarm After 3 Motion DetectionsThe alarm sounds only after motion has been seen three times.MediumBattery Low WarningGreen while the battery is above 7 V. When it falls below 7 V the red LED and buzzer warn.EasyChair Sit DetectorWhen someone sits on the pad, the green LED turns on and the buzzer beeps.EasyCloud Gas Level MonitorThe gas sensor level goes to the cloud. A local buzzer and red LED warn above 40 percent.MediumCurrent Meter (Ammeter) with LCDShows how much current flows through a battery-powered circuit.MediumDigital Volt and Amp MeterAn LCD shows a voltage and a current at the same time, like a bench power supply display.MediumDoor Opened SMS AlertA magnet switch on a door sends an SMS when the door opens.MediumFingerprint Intruder AlarmA stranger finger sets off the buzzer and the red light. Known fingers show green.MediumFire Alarm that Calls YouA flame sensor makes the module call the saved phone number and sound a local siren.HardFire Detection AlarmA flame sensor sets off a buzzer and light and switches on a water pump relay.EasyFire and Gas Alarm PanelA panel watches for flame and gas, shows the gas level and sounds the alarm. A teaching model only.MediumFlame Sensor SprinklerA flame starts the buzzer, the red light and a pump. A teaching model only, not a fire-protection product.MediumGPS Geofence AlarmAn alarm sounds when the GPS module leaves a 100 m circle around the home point.HardGPS Speed AlarmGreen below 60 km/h. Above 60 the red LED lights and the buzzer sounds.MediumGas Exhaust Mini FanA small fan runs at full speed when the gas level is high. A teaching model only.MediumGas Leak SMS Alert (GSM)When gas goes above 40 percent, a siren sounds and an SMS is sent to your phone.HardGas Level BarThe ring shows the gas level and the buzzer sounds above 60 percent. A teaching model only.EasyGas Level Bar with AlarmThe bar shows how much gas is in the air. Above 70 percent a buzzer sounds.MediumGas Level Ventilation FanAn exhaust fan starts when the gas level rises above 40 percent. A teaching model, not a gas safety device.MediumGas Voice WarningA recorded warning (track 3) plays when the gas level is above 40 percent.MediumGas Warning Sign on LED MatrixThe matrix shows a box when the air is fine and lights up fully with a buzzer when the gas level is high.MediumIntruder Alert with PIR and SMSWhen motion is seen in an empty room, the siren sounds and an SMS is sent.MediumKnock and Vibration AlarmAny shake or knock sets off a buzzer and a red LED.EasyLaptop Battery Life Saver ChargerThe charger relay switches off when the battery is above 80 percent and on again when it falls, to make a battery last longer.MediumLoRa Gas Alarm SenderA gas sensor sends an alarm over LoRa to a receiver kilometres away.HardLoRa Receiver with SirenKey 1 shows a yellow warning, key 2 shows a red light and a siren.MediumOvercurrent Cut-off with RelayThe relay switches the load on. If the current goes above 3 A, the relay turns the load off and an alarm sounds.MediumPanic Button SMSPress the button and an ALERT SMS is sent to a saved number.EasyPress 3 Times to UnlockThe red LED stays on until the button is pressed three times; then green shows unlocked.MediumRFID Unknown Tag AlarmA buzzer and a red LED warn when an unknown tag is shown.EasySD Card Gas Leak LoggerGas readings are recorded on an SD card. A buzzer sounds above 60 percent.MediumSmoke and Gas Leak DetectorThe LCD shows the gas level. Above 40 % the alarm sounds and a relay runs an exhaust fan.MediumTFT Gas Gauge with AlarmThe gauge turns red as the gas level rises. A buzzer sounds above 60 percent.MediumVehicle Tracker with SMS AlertIf the vehicle leaves the 100 m circle around the parking spot, an SMS is sent.HardWeight Limit AlarmGreen while the load is under 4 kg. Above 4 kg the red LED and buzzer warn of overload.Easy
Sound and music 15
Choose a Track with a KnobTurn the knob to choose track 0 (stop) to track 4.EasyDoorbell with Melody (MP3 Player)Press the button and a melody (track 1) plays; let go and it stops.EasyFlex Sensor Musical BendBend the flex sensor and the pitch goes up.EasyHourly ChimeThe buzzer sounds during the first minute of every hour, like a school bell.EasyIR Remote PianoKeys 1 to 8 on the remote play eight notes.MediumKeypad PianoKeys 1 to 8 play the notes C, D, E, F, G, A, B and the high C.MediumKnob Tone GeneratorTurn the knob to change the pitch from 100 to 3000 Hz.BeginnerLight ThereminWave your hand over the light sensor to change the pitch.EasyMelody PlayerThe passive buzzer plays the first line of "Twinkle Twinkle Little Star" while an LED flashes with each note.EasyMorse Code KeyPress the button to sound the buzzer and light the LED, like a telegraph key.BeginnerSOS Beacon (Morse Code)A red light and a buzzer send the distress signal SOS in Morse code: three short, three long, three short.EasySchool Bell on a Timetable (RTC)The bell rings in the first minute of each hour, but only from 9:00 to 15:59, the school day. At night and early morning it stays quiet.MediumSound Level IndicatorA loud sound lights the red LED. In quiet the green LED is on.EasySound Level RingThe ring lights up fully when the sound sensor hears a loud sound.EasyUltrasonic Pitch BuzzerMove your hand near the sensor and the pitch changes, like a theremin.Medium
Displays and counters 55
4-Digit Counter That Remembers (TM1637)A 4-digit display counts from 0 to 9999. Button 1 adds one, button 2 clears it, and the number is kept in EEPROM through a power cut.Medium7-Segment Digit CounterA single digit counts from 0 to 9 and starts again, like the display on a lift.BeginnerBattery Voltmeter with LCDShows the voltage of a battery or a solar panel up to 25 V.EasyBend Angle DisplayThe LCD shows how much the flex sensor is bent.EasyBinary Counter on 8 LEDsEight LEDs count from 0 to 255 in binary, one step every quarter second.MediumButton Press Counter on a DigitEvery press adds one to the number on the 7-segment display (0 to 9, then back to 0).EasyCountdown 9 to 0 with BeeperPress the button to start a 9 second countdown. At zero the buzzer sounds.EasyCountdown Ring TimerPress the button and the ring counts down eight seconds, one pixel at a time.EasyCountdown Timer with 4-Digit DisplayA display counts down from 10 to 0 and then the buzzer rings.EasyCounter That Remembers (EEPROM and LCD)A counter that does not forget. Button 1 adds one, button 2 sets it to zero, and the number is kept in the Arduino permanent memory (EEPROM) even when the power is off.MediumDigit Counter with MemoryEach press adds one to a digit display (0 to 9, then back to 0). After a power cut the same digit comes back.EasyDigital Clock with RTC and LCDA real-time clock chip keeps the time and the LCD shows hours and minutes.MediumDigital Weighing Scale with LCDA load cell and an HX711 board weigh things up to 5 kg and show the grams on the LCD.MediumDistance on a 4-Digit DisplayThe 4-digit display shows the distance in centimetres.EasyElectronic Dice on a DigitPress the button and the digit spins through 1 to 6 and stops on a number.EasyElectronic Dice with random()Press the button and the digit shows a random number from 1 to 6.EasyGPS SpeedometerShows your speed from the GPS module.EasyHealth Monitor: Pulse and TemperatureThe LCD shows pulse rate and body temperature. A buzzer sounds if the pulse is very high.HardHeart Rate Monitor with LCDShows beats per minute. The red LED warns if the rate is above 120 (for example after exercise).MediumIR Remote Key DisplayThe LCD shows the key number of the remote (1 to 9, 10 = 0, 11 = VOL-, 12 = PLAY, 13 = VOL+).EasyIR Remote to 7-Segment DigitPress 0 to 9 on the remote and the same number shows on the digit.EasyJoystick Arrow on LED MatrixPush the joystick to the right to see a right arrow; push it up to see an up arrow.MediumKeypad Key on the LCDThe LCD shows the code of the key you press (1 to 9, 10 = 0, 11 = *, 12 = #, 13 to 16 = A to D).EasyKeypad to 7-Segment DisplayPress 0 to 9 on the keypad and the same number shows on the digit.EasyKnob Reading on a 4-Digit DisplayTurn the knob and the display shows a number from 0 to 9999.EasyKnob Voltmeter on the LCDThe LCD shows the knob position as a percentage. A first step towards a voltmeter.EasyKnob to Binary DisplayTurn the knob and watch the number (0 to 255) appear in binary on eight LEDs.EasyKnob to Digit 0 to 9A seven-segment digit shows a number from 0 to 9 that follows the knob.EasyKnob-Controlled Digit DisplayTurn the knob and the digit shows a number from 0 to 9.EasyLCD Dice and Coin FlipA press shows a random dice number on the LCD.MediumLCD Seconds TimerThe LCD shows how many seconds the Arduino has been running.EasyLED Matrix Beating HeartA heart shows on the 8x8 matrix, then disappears, again and again, like a heartbeat.EasyLED Matrix Face SlideshowThe matrix shows a smiley, a heart, the letter A and a box, one after the other.EasyLap Timer with an IR SensorEach time a toy car passes the sensor the LCD shows how long the last lap took.MediumLevel Meter with a Knob (16 LEDs)Turn the knob and the row of LEDs fills up like a volume meter.EasyMatrix Pattern Picker with a ButtonEach press of the button moves to the next picture on the matrix.MediumMatrix Picture Chooser with a KnobTurn the knob to choose which of the 8 pictures is shown.EasyOLED Press CounterEvery press adds one to the number on the OLED (0 to 99).EasyOhm Meter with LCDMeasure the value of an unknown resistor and read it in kilo-ohms.MediumPhone Sends a DigitThe phone buttons F, B, L and R show 1, 2, 3 and 4 on the digit. Stop shows 0.EasyProduction Line Product CounterAn IR sensor counts products on a conveyor. After 10 the counter restarts and a buzzer sounds.MediumReaction Timer GameThe red LED lights up after 2 seconds. Press the button as fast as you can and the LCD shows your reaction time.MediumRunning Text on the LCDA message slides from right to left across the first line of the LCD, like a shop display.EasySeconds Counter on a DigitThe digit counts seconds from 0 to 9 and starts again.EasySolar Tracker with LCD Light ReadoutThe panel turns to the brighter side and the LCD shows both light readings.MediumSprint Timer (Start and Finish Gates)Cross the start gate and the timer starts. Cross the finish gate and your time shows on the LCD in milliseconds.MediumStopwatch with Start and Stop ButtonsButton 1 starts a stopwatch and button 2 stops it. The LCD shows the elapsed milliseconds.MediumStopwatch with Two Lap TimesButton 1 starts the stopwatch. Button 2 records lap 1, and a second press records lap 2. The LCD shows each lap time as you press.HardTFT Gauge with a KnobA number and a colour bar on the TFT follow the knob: green, orange, then red.EasyTemperature and Light MonitorThe LCD shows temperature and light level together.EasyTemperature in Tens on a DigitThe digit shows the temperature in tens of degrees: 3 means about 30 degrees.EasyTwo-Way People Counter with Room LightTwo IR sensors at a door count people going in and out. The room light stays on while at least one person is inside.HardUp-Down Counter with Two ButtonsButton 1 counts up and button 2 counts down on a digit display. Counting down stops at 0.MediumVisitor Counter That RemembersAn IR sensor at the entrance counts each visitor. The total stays after a power cut and a button clears it for a new day.MediumVisitor Counter with IR Sensor and LCDEach time someone passes the sensor the count goes up and shows on the LCD.Medium
Smart doors and home 37
433 MHz Remote 4-Load ControlKeys A to D of a radio remote switch four loads on. Key release switches the first load off.MediumAutomatic DoorThe door opens when someone comes near, waits, then closes.EasyAutomatic Hand Sanitizer DispenserPut your hand under the sensor and a small pump gives one dose of sanitizer.EasyBluetooth 4-Load Home ControlFour appliances are switched on and off from your phone by Bluetooth.MediumBluetooth AC Fan SwitchSwitch a fan on and off from your phone. The green LED shows the state.EasyBluetooth Door LatchThe ON button unlocks the latch (green) and OFF locks it again (red).EasyBluetooth Home Switch (Two Relays)Switch two relay-controlled loads from your phone with ON and OFF buttons.EasyClap Switch LampA loud sound switches the lamp relay on while the sound lasts.EasyCloud and Manual Control (Two Loads)Each load can be switched on from the internet or by a push-button on the wall. The wall button always works, even if the Wi-Fi is down.MediumCupboard Door LightThe light comes on when the door opens, as in a refrigerator.EasyDaylight Window BlindA servo opens the blind when it is brighter outside than inside and closes it otherwise.MediumDoor Opening Counter with MemoryA reed switch and magnet on a door count every opening. The total is kept in EEPROM and a button clears it.MediumEvening Lamp TimerThe lamp turns on at 6 pm and off at 11 pm every day.MediumFingerprint Attendance LightsEach saved finger has its own light. A stranger lights the red LED.EasyFingerprint Door Lock with ServoA saved finger opens the lock. A stranger finger keeps it shut and shows red.MediumFingerprint Safe (Relay Lock)Only finger 1 opens the safe (relay on). A stranger finger sounds the buzzer.MediumIR Remote 4-Relay ControlEight keys of a TV style remote switch four appliances on and off.MediumIR Remote Lamp SwitchPLAY switches the lamp on and VOL- switches it off, from across the room.EasyIR Remote: Fan and Light SwitchKeys 1 and 2 switch the fan on and off. Keys 3 and 4 switch the light on and off.MediumIoT Cloud 4-Load DashboardA phone dashboard has four switches. Each one runs a relay and its own green LED shows the true state at the Arduino.MediumKeypad Door Lock (Single Key Code)Press 5 to open the lock (green) and A to lock it again (red). A real lock would use a longer code.MediumPush-Button Servo LatchButton 1 opens the latch (green), button 2 locks it (red).EasyRFID Access Lights (Green or Red)A known card turns the green LED on. An unknown tag turns the red LED on.EasyRFID Door Lock with ServoCards A and B open the lock (servo at 90 degrees). An unknown tag keeps it shut and shows red.MediumRFID Guest and Owner LightsThe owner card lights green and the guest card lights yellow.EasyRFID Owner-Only RelayOnly the owner card (card A) switches the relay on. Other cards do nothing.MediumRFID Vehicle Barrier GateA car owner holds a registered card to the reader and the barrier arm lifts for three seconds, then closes. An unknown card does nothing.MediumRoom Fan That Follows MotionThe fan is on when there is somebody in the room and off when the room is empty.EasySmart DustbinThe lid opens when your hand comes near and closes when you move away.EasySmart Room ControllerThe light comes on when somebody is in the room and it is dark. The fan starts above 30 degrees. The LCD shows both values.HardTimer: Four Loads by the ClockFour loads switch on and off at different hours of the day: geyser, porch light, pump and fan.HardTouch Controlled FanTouch the pad and the fan runs; let go and it stops.EasyTouch LampTouch the pad and the lamp comes on.EasyVisitor Chime with Welcome MessageA shop entrance plays a two-note chime when someone walks in.EasyWeb-Controlled Fan with RelaySwitch a fan on and off from the internet. A green LED shows the fan is on.MediumWeb-Controlled LampTurn a lamp on and off from a web page. The Arduino checks a cloud switch every few seconds.MediumWi-Fi 4-Load Control (Web Buttons)Four web buttons switch four appliances through four relays, using an ESP-01 Wi-Fi module and a cloud service. Any phone or computer with internet can use them.Medium
Theory and info pages (no simulation) 9
3-Phase Motor Speed Control with a VFD and ArduinoHow a variable frequency drive changes the speed of a 3-phase induction motor, and how an Arduino can give it a speed signal and a run command safely.Info pageBLDC Motor with an ESC and ArduinoHow a brushless motor and its speed controller (ESC) work, and how an Arduino sets the throttle with a servo-style signal.Info pageBrain-Controlled Wheelchair (Learning Model)How a headset that reads brain waves (EEG) can steer a small robot chair with an Arduino, and why safety checks come first.Info pageESP32-CAM Object Detection (Learning Page)How to stream video from an ESP32-CAM board over Wi-Fi and detect objects with a small AI model running on a computer.Info pageMobile Phone Charger: How It Works and a Safe Li-ion ChargerHow a 5 V mobile charger turns mains into USB power, and how a Li-ion cell is charged safely with a TP4056 module.Info pageOscilloscope and Function Generator BasicsWhat an oscilloscope screen shows, how to read the time and voltage grid, and how an Arduino can give test signals.Info pagePrepaid Energy Meter (Learning Model)How a prepaid meter counts pulses from an energy meter, deducts money from a balance and cuts the supply with a relay, shown with a safe model.Info pageTransistor and Capacitor Basics for Arduino BuildersLearn how a transistor switches a load that an Arduino pin cannot drive, and how a resistor and capacitor make a time delay, with two calculators.Info pageUnderground Cable Fault Locator (Learning Model)How the distance to a short-circuit in a cable is found from its resistance, with an Arduino model that uses resistors as cable sections.Info page