Best Sensors for Arduino Projects: Complete List by Use Case

DHT11 — Temperature and Humidity

• Price band: ₹40–₹100

• Interface: Single-wire digital

• Typical accuracy: Temperature ±2°C; humidity ±5% RH

• Project idea: Build a room temperature and humidity display.

DHT11 is a low-cost starting point for basic environmental monitoring. Its limited measurement range and accuracy make it less suitable for precision applications.

DHT22 (AM2302) — Temperature and Humidity

• Price band: ₹100–₹250

• Interface: Single-wire digital

• Typical accuracy: Temperature ±0.5°C; humidity around ±2–5% RH

• Project idea: Build an indoor climate monitor with temperature alerts.

Choose DHT22 when you need a wider measurement range and better temperature accuracy than DHT11.

DS18B20 — Digital Temperature

• Price band: ₹80–₹250

• Interface: 1-Wire digital

• Typical accuracy: ±0.5°C over its specified central range

• Project idea: Monitor water temperature in a tank or aquarium.

The probe-style version is useful where the sensing element needs protection from moisture. Check the probe's sealing and temperature rating before using it in water.

BME280 — Temperature, Humidity and Pressure

• Price band: ₹200–₹500

• Interface: I2C or SPI

• Typical accuracy: Temperature around ±1°C; humidity around ±3% RH; pressure around ±1 hPa under specified conditions

• Project idea: Build a compact weather station that records pressure and estimates altitude changes.

BME280 combines three environmental measurements in one module. Verify the actual sensor chip because some inexpensive boards use different components.

HC-SR04 — Ultrasonic Distance

• Price band: ₹50–₹120

• Interface: Trigger and echo digital pins

• Typical accuracy: Often specified around ±3 mm under suitable conditions

• Project idea: Build an obstacle-avoiding robot or a non-contact distance meter.

It measures distance from the time taken by an ultrasonic pulse to return. Soft, angled, or irregular surfaces can affect readings. The common module uses a 5V echo signal, so check compatibility with your board.

HC-SR501 — PIR Motion

• Price band: ₹50–₹150

• Interface: Digital HIGH/LOW output

• Accuracy: Not expressed as distance accuracy; performance depends on motion, placement, and settings

• Project idea: Switch on a light when a person enters a room.

A PIR sensor detects changes in infrared energy associated with moving warm objects. It detects motion, not the exact distance or identity of a person.

IR Obstacle Sensor — Near-Object Detection

• Price band: ₹30–₹100

• Interface: Usually digital; some modules provide analog output

• Accuracy: Detection threshold varies with surface reflectivity, distance, and ambient light

• Project idea: Detect obstacles or track a line with a small robot.

IR obstacle modules are inexpensive and easy to use, but their detection distance is usually short and varies with the target material and sensor adjustment.

VL53L0X — Time-of-Flight Distance

• Price band: ₹150–₹450

• Interface: I2C

• Accuracy: Depends on distance, target reflectivity, ambient light, and module implementation

• Project idea: Build a compact robot that measures distance to nearby objects.

This sensor estimates distance using the travel time of emitted light. It is useful when a small optical module is preferable to an ultrasonic sensor.

LDR — Light Detection

• Price band: ₹15–₹80

• Interface: Analog voltage through a resistor divider; modules may also provide digital output

• Accuracy: Relative light level; not a calibrated lux measurement

• Project idea: Build an automatic night light.

An LDR changes resistance with light intensity. Pair it with a resistor to create a voltage divider that an Arduino analog input can read.

BH1750 — Ambient Light Intensity

• Price band: ₹100–₹250

• Interface: I2C

• Accuracy: Provides a lux measurement; accuracy depends on the module, light spectrum, and operating conditions

• Project idea: Automatically adjust display brightness based on room lighting.

Unlike a basic LDR circuit, the BH1750 reports a digital light-intensity value in lux, making it more useful when you need a quantitative reading.

TCS34725 — Colour Detection

• Price band: ₹150–₹400

• Interface: I2C

• Accuracy: Measures red, green, blue, and clear-channel values; colour accuracy depends on illumination and calibration

• Project idea: Build a robot that sorts coloured objects.

Use consistent lighting and calibrate the sensor against known colours for more repeatable results.

MPU6050 — Accelerometer and Gyroscope

• Price band: ₹100–₹250

• Interface: I2C

• Accuracy: Configurable acceleration and angular-rate ranges; bias and drift require consideration

• Project idea: Build a tilt-controlled robot or a self-balancing robot prototype.

The MPU6050 measures acceleration along three axes and angular velocity along three axes. It does not directly provide a perfectly stable compass heading.

ADXL345 — Acceleration and Tilt

• Price band: ₹100–₹250

• Interface: I2C or SPI

• Accuracy: Depends on selected range, calibration, and sensor mounting

• Project idea: Detect a device being tilted, shaken, or dropped.

It measures acceleration on three axes. Static tilt can be estimated from gravity when the device is not undergoing significant motion.

Capacitive Soil-Moisture Sensor

• Price band: ₹50–₹180

• Interface: Usually analog output

• Accuracy: Relative moisture reading; calibration depends on soil type and conditions

• Project idea: Build a smart plant monitor that alerts you when soil becomes dry.

Capacitive probes are often preferable to inexpensive exposed resistive probes because they reduce electrode corrosion. They still need calibration for meaningful moisture thresholds.

MQ-2 — Smoke and Flammable Gas Response

• Price band: ₹80–₹200

• Interface: Analog output; many modules also include a digital threshold output

• Accuracy: Not a selective or calibrated gas concentration measurement without suitable calibration and conditions

• Project idea: Build an educational gas-response indicator with a buzzer alert.

MQ-2 modules need warm-up time and can respond to several gases. They should not be treated as certified household gas alarms or life-safety equipment.

Water-Level Sensor — Liquid Detection

• Price band: ₹25–₹100

• Interface: Usually analog output; module versions vary

• Accuracy: Typically a relative level or wet/dry indication, not a calibrated depth measurement

• Project idea: Build a tank-level alert or an automatic water-refill prototype.

Basic conductive boards are inexpensive for demonstrations, but prolonged immersion can cause corrosion. For reliable long-term use, choose a sensor designed for the liquid and installation environment.

Sound Sensor Module

• Price band: ₹30–₹120

• Interface: Usually digital threshold output; some modules provide analog output

• Accuracy: Basic modules indicate relative sound level or threshold crossings, not calibrated sound pressure

• Project idea: Build a clap-triggered LED or sound-activated display.

These modules are useful for simple sound events. For accurate decibel measurement, use a microphone and interface designed and calibrated for that purpose.

TTP223 — Capacitive Touch

• Price band: ₹20–₹80

• Interface: Digital output

• Accuracy: Detects touch or proximity within its design limits; sensitivity depends on the module and installation

• Project idea: Create a touch-controlled lamp or a simple touch button.

A capacitive touch module can replace a mechanical button in many simple interfaces, but nearby conductive materials and wiring can affect its response.

Hall-Effect Sensor — Magnetic Detection

• Price band: ₹25–₹100

• Interface: Usually digital output for switch-type modules

• Accuracy: Depends on magnetic sensitivity, magnet strength, and placement

• Project idea: Count wheel rotations or detect whether a door is open using a magnet.

Hall-effect switches detect magnetic fields without physical contact. For rotation counting, attach a magnet to the rotating part and count the output transitions.