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