Sensor

Sensor v/s Detector

Sensor: collects and gives data according to the situation or Surroundings.

Detector: the device to which that information is transferred and gives detection output.

Light Related Sensors

EXAMPLE : Movement Detector --- has a PIR sensor that senses infrared radiation, gives amount to an integrated chip, and will calculate if there was a movement or not. If movement is detected, the detector will have a high output and vice versa.

Detector needs a sensor - a device or module which sense changes in environment and sends that information

Color Sensor

Will apply white light and sense frequency of each color reflected

Has a photo dial for RGB (red, green, blue)

Heart Pole Sensor

Simple optical heart sensor with amplification and noise cancellation -- helps for reliable pulse reading

PIR (passive infrared radiation)

Senses change in radiation

Since human bodies radiate heat in form of infrared radiation, it can detect movement, by sensing changes in radiation

Infrared Distance Sensor

Sends infrared beam to an object, detects the bounce beam of light and depending on where it touches sensor, it can detect bounce angle and distance to object

Infrared light used as we're surrounded by visible light, that will result in a lot of noise

Laser Based Distance Sensor

Very small, can measure up to 2 meters, very precise for distance

Detects distances or gestures

Senses distance with the reflected laser beam

Direct Infrared Sensor

It has an infrared LED which sends light and the photo transistor will detect the light reflected on the object

Could also be used as a switch; emitter and receiver can detect if something is in between them

EXAMPLE: Infrared Remote --- more infrared light, higher output, or if its digital, then will get higher when it comes close to sensor. Has an amplifier.

LDR (light dependent resistor)

Changes value according to the amount of light it receives

Other Groups

IMU Module

Senses gyro forces and accelerations; these values can help calculate angle as well

Can be used in drones

Can detect accident, a peak value might imply a fast change inn acceleration

Can also detect movement, if it senses gyro forces and accelerations then it means the object moved

Magnetometer

Measures earth magnetic field

Can be used to create compass and orient people in space

Can also be used in drones, along with a GPS module

Atmospheric Pressure Sensor

Measures pressure to determine altitude

Higher in the air, lesser pressure

General

Gas Sensor

Senses specific types of gases like flammable gases, air quality or alcohol in the air that one exhales

Also can detect changes in normal air percentage of gases

Uses an amplifier, and occasionally an analog

Distance Sensor

Uses ultrasound pulses -- sends sound wave, detects bounced wave, and detects time to get it back

Thermocouple Voltage Sensor

Thermocouple is a component which creates small voltage drop when it's heated up

Knowing temperature versus voltage drop, one can understand temperatures

Thermistor / Temperature Dependent Resistor

When thermistor heated up, resistance will change and so will the voltage divider output

Current Sensor

Connect this module in parallel with load, it will measure current of load

Uses resistor as a load and a power controller to vary the voltage

Hall Sensor

Detects magnetic field

Has a linear output

If connected to 5 volts and ground, and if magnet placed near module, output will increase or decrease accordingly

Can be used as switch or encoder - applicable for many projects

ADC

Some say not a sensor but it senses analog value

Recommended for precise recordings