Study of Hardware Sensors

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To develope products using sensors, it is essential to have a knowledge of variety of sensors. This page lists type of sensors, demonstrates about its characteristics and how they can be applied to the real world.

Distance Sensor

  Ultrasonic Infrared Laser
Method Sound Light Light
Frequency High Low -
Cons distance mesurement Object detection Accuracy
Pros Environmental factors (observe signal by soft objects) inaccurate distance measurement Cost

*Laser beam is often used to measure long distance.

Ultrasonic

Ultrasonic sensors often enhances distance measurement to the object very accurately.

PARTS Datasheet
parallax: PING PING
HC-SR04 (Similar to PING but cheaper) HC-SR04

Infrared

One of the great features of using infrared sensor is thermal emission. This enhances object come and go by thermal emission. However, thermal emission should be taken carefully depends on environmental factors. the sensor only able to detect object within a range but cannot accurately sense distnace.

PARTS Datasheet
Infrared Sensor Switch Foo
Compound Eye Foo

Compound eye sensor is consisted of a number of infrared-sensitive transistor and LED

Types:

  • Passive infrared sensor: Senses thermal radiation transferred to infrared.

  • Active infrared distance sensor: Detects returned sent light from infrared. This notifies distance in a range.

Applications:

Hand Dryer, Water tab, rubish bin.

Smoke and Gas Sensor

There are variety of sensors which senses different kind of chemicals as show below. MQ2 is one of the cheapest Analog sensor used among developers.

PARTS Application Datasheet
MQ-2 LPG
I-butane
Propane
Methane
Alcohol
Hydrogen
Smoke
Foo
MQ-3, MQ-303A Alcohol Checker
Breathalyser
Foo
MQ-4 CH4
Natural Gas
Foo
MQ-7 Carbox Monoxide Foo
MQ-8 Hydrogen Foo
MQ-9 Carbon Monoxide
CH4
LPG
Foo

Switches

Touch Sensors - work the same way as the buttons which need voltage and ground lines.

Types
Buttons
Microswitch
Potentiometer
QT 113 - Touch Sensor
FlexiForce - analogRead
Touch Sensors

Movement

Types Notes
Tilt Sensor adc
vibration sensor adc
rotary encoder counts the rotation of the object
Thumbstick used in joystick of playstation. two types: 3 pins and 5 pins
PIR sensor various range of products depends on sensing distance and angle.

Light

Types Notes
Flame sensor KY-026
Light-dependent resistor (LDR) visible ray resistors
Line detection (line tracer)  
color detection  
color display (RGB LED)  

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