Electronics and robotics
Electronics and robotics projects for class 11 and 12: 60 ideas.
Each project below opens to its own page with what it shows, the science behind it, the materials, safety, step-by-step instructions, what you should see and viva questions. Many can be made from things at home; where a kit helps, the page links one.
Other subjects for class 11 and 12: Physics, Chemistry, Biology, Maths, Earth and space, Environment, Computing and coding.
Smart dustbin with Arduino
An ultrasonic sensor sends out a pulse of sound and times its echo to measure distance. When a hand comes close, the Arduino tells a servo motor to lift the lid.
Obstacle-avoiding robot
The robot measures the distance ahead with an ultrasonic sensor. When something is too close, the program stops, turns and looks for a clear path, driving the motors through a motor driver.
Line follower robot
IR sensors shine infrared light at the floor: white reflects it and black absorbs it. The controller reads which sensor sees the line and steers the motors to stay on it.
Automatic plant watering system
A soil moisture sensor gives a reading that changes with the water in the soil. When the soil is dry, the Arduino switches on a small pump until it is moist again.
Solar tracker with LDRs
Two LDRs compare the light on either side of the panel. The microcontroller turns a servo towards the brighter side, so the panel keeps facing the Sun and collects more energy through the day.
Automatic railway gate control
IR sensors detect the train before and after the crossing. The controller closes the gate with a servo and sounds a buzzer as a train approaches, and opens it again once the train has passed.
Fire-fighting robot
Flame sensors detect the infrared light from a flame. The robot steers towards the strongest reading and switches on a small pump to spray water at it.
Gas leakage detector
The resistance of an MQ-series gas sensor changes when LPG or smoke is in the air. The controller reads it and sounds a buzzer above a set level.
Bluetooth-controlled car
A phone app sends commands over Bluetooth to an HC-05 module. The Arduino reads them and drives the motors forwards, backwards, left and right through a motor driver.
Phone web page that switches a 12 V LED strip through an ESP8266 relay
A NodeMCU (ESP8266) joins the home Wi-Fi, runs a tiny web server and turns a relay on or off when a phone browser taps a button. The relay switches a 12 V LED strip, so the whole thing is a low-voltage copy of a smart switch.
PIR corridor light that stays on for a set time after movement
A passive infrared (PIR) sensor detects the heat of a moving person. An Arduino switches a 12 V LED strip on through a relay and keeps it on for a timer period that restarts with every new movement, so the light never cuts out while someone is still walking.
Kitchen gas alarm that starts a 12 V exhaust fan through a relay
An MQ-2 gas sensor changes resistance when LPG, butane or smoke touches its heated element. The Arduino compares the reading to a threshold, sounds a buzzer, flashes a red LED and switches a 12 V DC fan through a relay to clear the air.
Flame sensor store room alarm with a small sprinkler pump
An infrared flame sensor module detects the flicker and wavelength of a flame from a metre away. The Arduino sounds an alarm and runs a 5 V submersible pump through a relay so a tiny sprinkler sprays water on the model store room.
RFID door latch that pulls a 12 V solenoid for tagged cards only
An RC522 reader reads the unique ID of a 13.56 MHz card or key fob. If the ID is in a list stored in the sketch, the Arduino fires a relay for three seconds that pulls a 12 V solenoid bolt open, and an LCD greets the user by name.
Voice commands from a phone app switch two 12 V lights over Bluetooth
A free Android voice app converts speech to text and sends it over Bluetooth to an HC-05 module. The Arduino matches words such as "light on" or "fan off" and drives relays that switch 12 V LED lamps and a 12 V fan.
Automatic curtain that opens at dawn using an LDR and a DC motor
An LDR measures daylight, the Arduino decides open or closed, and an L298N driver runs a geared DC motor in either direction to pull a string curtain across a model window. Two limit switches stop the motor at each end.
Overhead tank level on your phone with automatic pump control (ESP8266)
An ultrasonic sensor on the tank lid measures the distance to the water surface. The ESP8266 converts that to a percentage, shows it on a phone page, and switches a 5 V pump through a relay to refill when the level is low and stop when full.
Gas leak detector that turns a model cylinder valve shut with a servo
An MQ-6 LPG sensor senses a leak and an Arduino rotates a high-torque servo fitted to a model regulator knob to the closed position, sounds a buzzer, and shows the gas level on an LCD. It demonstrates automatic shut-off, not just an alarm.
PIR intruder alarm that sends a phone message through an ESP8266
A PIR sensor watches a room; when it triggers while the system is armed, a NodeMCU sends a message to the owner through a free bot on a messaging app and sounds a local buzzer. The system is armed and disarmed by a message from the phone.
Earthquake alarm with an MPU6050 that cuts a 12 V supply through a relay
An MPU6050 accelerometer measures shaking on three axes. When the vibration stays above a level for a short time, the Arduino sounds a siren, flashes a light and opens a relay that cuts a 12 V model lighting circuit, as a real system might cut gas or power during a quake.
Two-zone drip irrigation with soil probes and a phone dashboard (ESP8266)
Two soil moisture probes in two pots each control their own 5 V pump through a relay, and a NodeMCU shows both moisture levels and pump states on a phone page. It demonstrates zone-wise watering, the way a farm drip system treats each bed separately.
Model greenhouse that runs a fan and a mist pump from DHT11 readings
A DHT11 inside a clear box greenhouse reads temperature and humidity. The Arduino switches a 12 V fan when it gets too hot and a 5 V mist pump when it gets too dry, keeping the plants in a chosen band and showing the state on an LCD.
Water turbidity meter using a laser pointer and an LDR
A laser beam passes through a sample bottle to an LDR; cloudy water scatters light and the LDR reading falls. The Arduino converts the reading to a clarity scale calibrated with known mixtures and shows it on an LCD, a low-cost version of a turbidity meter.
Tipping bucket rain gauge with a reed switch counted by Arduino
Rain collected by a funnel fills one side of a tiny see-saw bucket; when it tips, a magnet passes a reed switch and the Arduino counts one tip. Knowing the volume per tip and the funnel area gives rainfall in millimetres on an LCD.
Grain store humidity alarm with an ESP8266 that warns the phone
A DHT11 inside a model grain bin watches humidity; stored grain spoils and grows mould when air humidity stays high. The NodeMCU shows the reading on a phone page, sounds a buzzer and sends an alert when humidity stays above a limit for a set time.
Indoor air quality logger with MQ-135, an OLED and a phone graph (ESP32)
An MQ-135 sensor responds to carbon dioxide, ammonia, smoke and other indoor pollutants. An ESP32 shows a rolling value on an OLED, keeps the last hour of readings in memory and draws them as a graph on a phone page, so the effect of cooking, incense or a closed room is visible.
Cup anemometer with a Hall sensor and wind vane on an OLED
Three plastic cups on a spindle spin in the wind and a magnet on the spindle passes a Hall sensor once a turn. The Arduino times the pulses to compute wind speed, reads a potentiometer on a wind vane for direction, and shows both on an OLED.
Flood early warning post with an ultrasonic level sensor and a three-stage siren
An ultrasonic sensor on a model bridge watches the water level in a model river. As the level rises past three marks the NodeMCU lights green, yellow and red LEDs, sounds a siren at the red mark and shows the level on a phone page so a village downstream could see it.
Dual-axis solar tracker with four LDRs and two servos
Four LDRs in a cross with small dividing walls sense which side is brighter. Two servos tilt a small solar panel left-right and up-down until all four read the same, so the panel faces the sun. A voltmeter reading from the panel shows the gain over a fixed panel.
Car parking sensor with an Arduino whose beeps speed up as the wall nears
An ultrasonic sensor measures distance from the time an echo takes to return. The Arduino turns this distance into LED steps and a beeping speed, like the sensor in a car bumper.
Digital room thermometer with an LM35 and LCD showing the day’s minimum and maximum
The LM35 gives 10 millivolts for every degree Celsius. The Arduino reads this voltage with its analog input, converts it to degrees and shows the present, lowest and highest readings on a screen.
Sonar radar sweep: a servo-mounted ultrasonic sensor mapping a room on a laptop
Turning an ultrasonic sensor on a servo and sending angle and distance to a laptop builds a polar map of the objects around, like a radar sweep. It combines timing, servo control and serial communication.
Digital lap stopwatch with an Arduino, three buttons and an LCD
The millis() timer counts milliseconds since the board started. Storing the start time and subtracting it from the present value gives elapsed time, which can be shown to a hundredth of a second.
Reaction time tester with random delay and false start detection (Arduino)
The time between a light and your button press is your reaction time, usually around 0.2 to 0.3 seconds. A microcontroller timer measures it to a thousandth of a second, so you can compare people and conditions.
Model door lock opened by a 4 digit keypad code and a servo bolt
The Arduino compares the keys typed with a stored code and turns a servo to slide a bolt only when they match. After three wrong tries it locks out for a minute, showing basic access control logic.
RFID card door opener with an MFRC522 reader that logs who entered
A passive RFID card has no battery: the reader powers it through radio waves and reads its unique ID. The Arduino checks the ID against a list and opens a servo door for known cards only.
Fingertip pulse sensor showing heartbeats on the Serial Plotter and a beat LED
Each heartbeat changes the amount of blood in the fingertip, and so changes how much light passes through or reflects. A green LED and a light sensor see this tiny change, which the Arduino turns into a beat rate.
Four-servo robot arm that copies the angles of four knobs
Each joint of the arm is a servo whose angle is set by a PWM signal. Reading four potentiometers and mapping each to 0 to 180 degrees lets you pose the arm by hand-turned knobs and pick up light objects.
Mini sumo robot that finds its opponent and stays inside the white-edged ring
Sumo robots search for an opponent, push it out of a black ring and stop at the white border. This needs edge detection with reflective sensors and distance sensing, with simple decision priority in the code.
Two-gate speed meter that times a toy car with infrared sensors
Speed is distance divided by time. Two infrared beams a known distance apart start and stop a timer as a car passes, so its speed can be found to a good accuracy and compared with a stopwatch.
Hand-wave theremin: an ultrasonic sensor that plays higher notes as your hand nears
The Arduino turns the distance of your hand into the frequency of a tone, so you can play music in the air. It shows how a sensor reading can be mapped to a sound.
Barometer and altimeter with a BMP280 that detects which floor you are on
Air pressure falls with height, by about 12 pascals for each metre near the ground. A BMP280 sensor can measure this so precisely that it can tell one floor of a building from the next.
Internet clock showing Indian time on an OLED, set automatically by NTP
Computers set their clocks by asking time servers over the internet using the Network Time Protocol. A NodeMCU can do the same and display accurate Indian Standard Time without a clock chip.
Stepper motor turntable that turns a product by 10 degrees for 360 degree photos
A stepper motor turns in exact small steps instead of spinning freely. The Arduino counts steps to rotate a platform through an exact angle, which is how 3D scanners, printers and camera sliders position things.
Medicine time reminder box with a DS3231 clock, buzzer and LCD
A real time clock chip keeps time even when the board is off, using a coin cell. The Arduino compares it with set alarm times and sounds a buzzer until a button is pressed.
Touch-free soap dispenser with an ultrasonic sensor, relay and small pump
When a hand comes within about 10 cm, the sensor detects it and the Arduino runs a small pump for a fraction of a second. It shows how sensors, relays and timers are combined in a hygiene device.
Digital kitchen scale built from a load cell, an HX711 amplifier and an Arduino
A load cell is a metal bar whose resistance changes by a tiny amount when it bends under a weight. The HX711 amplifies and digitises this change so the Arduino can show the mass in grams.
Temperature-controlled 5 V fan with PWM speed steps and a logic-level MOSFET
Pulse width modulation switches a fan on and off thousands of times a second; the fraction of time it is on sets the average power and speed. The Arduino raises the duty cycle as the temperature climbs, as a computer cooling fan does.
Cricket scoreboard with MAX7219 LED matrices, scoring buttons and over counter
A MAX7219 chip drives a whole 8 x 8 LED matrix from three wires. The Arduino keeps the score, wickets and balls in variables and shows them as scrolling or fixed text, like a small scoreboard.
Old TV remote that switches three LEDs and a servo through an IR receiver
A remote control flashes an invisible infrared LED in a coded pattern, and a receiver module decodes it into a number. The Arduino can read that number and act on it, so any old remote becomes a controller for your projects.
555 monostable delay timer: calculated against measured pulse width
Staircase and passage lights, bell pushes and sample-and-hold stages all need a pulse of fixed length after a single trigger. A 555 timer in monostable mode gives such a pulse, and its length is set by one resistor and one capacitor. The project tests how close the formula T = 1.1 RC is to what a stopwatch measures.
LM317 adjustable 1.25 to 12 V bench supply with a load regulation test
Every student lab needs a variable DC supply, and shop-bought ones are costly. An LM317 regulator with two resistors gives an adjustable output. The project builds one from a 15 V adapter output and tests how much the output falls when the load current rises, which is the load regulation.
AA cell capacity tester with a constant-current load and Arduino logging
Rechargeable and cheap zinc cells carry a printed capacity that is often much higher than the truth. A constant-current load with an Arduino logger finds the real milliamp-hours of a cell by recording voltage until the cell reaches its cut-off.
Joule thief that lights an LED from a nearly flat 1.2 V cell
A single cell below 1 V cannot light a white LED, which needs about 3 V. A joule thief is a tiny blocking oscillator that pumps energy from the cell in short bursts and steps the voltage up. The project builds it and measures the pulse frequency, the output voltage and the extra running time.
LM386 audio amplifier with measured gain and frequency response
Small radios, intercoms and toy speakers use small audio power amplifiers. The LM386 gives gain of 20 or 200 with a few components. The project builds one and measures the voltage gain and how it changes with frequency, so that a student learns to read a Bode-style plot.
TV remote code decoder with a TSOP1738 receiver and Arduino
Infrared remotes talk to TVs and fans by sending pulses of 38 kHz light. An Arduino with a TSOP1738 receiver can decode the pulse train of each button, which teaches the idea of a protocol, and can then switch low-voltage loads from any old remote.
Thermistor thermometer calibrated with the Steinhart-Hart equation
A thermistor is cheap and sensitive but its resistance is not linear with temperature. By measuring resistance at three known temperatures and fitting the Steinhart-Hart equation, you can build a digital thermometer more accurate than a basic LM35 and show how calibration removes error.
LM2596 buck converter module: efficiency against load current
Phone chargers, LED drivers and solar chargers use switching converters because linear regulators waste power as heat. The project tests a ready-made LM2596 buck module and compares its efficiency with an LM7805 linear regulator at the same load.
PWM speed controller for a 12 V DC motor with an IR tachometer
Fans, conveyors and e-rickshaws vary motor speed by switching power on and off very fast rather than wasting it in a resistor. The project builds a PWM controller, measures real rpm with an infrared sensor and plots speed against duty cycle.
HX711 load cell kitchen scale with calibration and an error table
Digital weighing scales in shops use strain-gauge load cells, which change resistance by a tiny amount when bent. An HX711 amplifier and Arduino turn that into grams. The project calibrates the scale with known masses and reports its accuracy.