How Sound Sensor Works, How Proximity Sensor Works
In my ARDUINO projects I will be using different types of sensors as per the specific requirements, in this article I will be going in depth on 2 types of sensors i.e How Sound sensor works and How Proximity Sensor Works
How Sound sensor works
How Infrared sensor works
If you are Arduino Project enthusiast then definitely you might have seen or used this components in any of your projects, these are called sound sensor/sound detection sensor(first image) and Infrared sensors(second image). I will show you how these sensors works in detail along with it’s principle of working, Circuits and description of each components and their functions
Have you ever thought across how this sound detection sensor works?
The Principle of working is similar to human ears, in our case when sound is emitted by any source in audible frequency range it gets picked up by our Eardrum which causes it to vibrate and hence we can feel sound(this is simplest explanation), but in case of sound sensor Diaphragm vibrates and serve as ears to ARDUINO!
Parts used in sound sensor
Electret condenser microphones(pin type)
W104 potentiometer
LM 393 Operational amplifier
Sound detection LED indicator
Power indicator LED
4 Resistor and 2 SMD LED’s
Now let’s go in depth to see how actually each part contribute to overall functioning of sound sensor
Working of Condenser microphone
When sound waves are emitted by any audio source for example music from speaker, human voice or sound from vehicle the diaphragm which is one of the part inside mic vibrates, As a result of vibration capacitance changes
So a small voltage is produced because of changes in distance between diaphragm(front plate) and back plate
These 2 plates are separated by spacer
The voltage change varies as per the intensity of sound(shown as arrows in above image) which hits diaphragm
These output signal is of very low strength and hence these low voltage signals needs to be amplified
For the purpose of amplification amplifier is used
Amplifier picks up low strength signals and amplify to signals which is detectable
LM 393 Operational amplifier Pin diagram
| Pins | Functions |
| Pin1 | Output 1 |
| Pin2 | Inverting input |
| Pin3 | Non inverting input |
| Pin4 | GND |
| Pin5 | Non inverting input |
| Pin6 | Inverting input |
| Pin7 | Output 2 |
| Pin8 | Vcc |
LM 393 Operational amplifier features
| Specs | Ratings |
| Input voltage | 2v DC to 36v DC |
| Differential input voltage | Power supply voltage |
| Input bias current | 25 nA |
| Input offset current | 5.0 nA |
| Input offset voltage | 5v mV |
| Lead temperature | 2600C |
W104 potentiometer
This is a trimmer potentiometer with 100kOhms value used for tuning, here by turning the knob with the help of small screw on top of potentiometer sensitivity of condenser microphone can be adjusted
Clockwise turn of screw leads to more sensitivity
Counter clockwise turn for less sensitivity
Output and input pins of sound sensor
A0 connects to analog pin in Arduino
Gnd/G for negative power supply
+ for Positive power supply (5v supply)
D0 connects to digital pin in Arduino
Advantage
Sensor Module available in very less price and Easy to use
Disadvantages
Only detects sound presence and Can’t recognize frequency
Applications
I have used this sensor in making multiple Arduino projects to name few music reactive ARGB lights, voice controlled lights and many more
How infrared sensor works
Infrared sensor is an optoelectronic component used to detect obstacles, hence the use of this sensor is used in making obstacle sensing projects such as obstacle avoiding robots
Principle of working
Infrared transmitter transmits IR signals when board is supplied with power
In the process of transmission if it detects any obstacles in the path those signals get reflected back
This will be received by IR receiver
The received signals will be having low strength and hence to amplify the signals Op-amp is used
The sensitivity can be increased or decreased with the help of trimmer potentiometer attached to board
Turn the screw to vary the sensitivity
Note: Maximum range of this sensor is 20cm, it means it can detect object at the max distance of 20cm and this distance can be lowered by spinning potentiometer
For example: if you are making obstacle avoidance robot and if u want your robot to change its direction when it finds an object in the range of 10cm it can be done by turning the knob
IR Sensor module consists of
Infrared transmitter
Infrared receiver
LM358 op amp
Potentiometer
Infrared transmitter looks very similar to LED diode but in case of LED diode visible light is emitted but in IR transmitter infrared light is transmitted(name itself says everything transmitter= transmitting)
Tip to see IR light: The remote control of TV uses IR sensor to send commands to your television, to see the IR light switch on mobile camera and face it towards IR bulb in remote and randomly press any button on remote you can see IR Light! Thank me later if you Didn’t knew this J
Pin diagram of LM358 Operational Amplifier, all the pin i/o is given in table below
| 1st pin | Output 1 |
| 2nd pin | Threshold 1 |
| 3rd pin | Input 1 |
| 4th pin | GND |
| 5th pin | INPUT 2 |
| 6th pin | Threshold 2 |
| 7th pin | Output2 |
| 8th pin | Vcc |
Potentiometer
Here the same 3362 potentiometer with 10k ohm is used, same specifications as given in above description
Output pins of Infrared sensor
Out is used for signal output
GND is for negative power supply
Vcc is for positive power supply
Advantages
Simple to use and Low cost
Disadvantages
Limited to 20cm length, hence can’t be used for large applications
Infrared receiver is sensitive to light hence may cause interference
Applications
Though the applications are endless to name some
Can be use to make obstacle avoiding car/robot
Can be used to make touchless hand wash liquid dispenser
Used to make IR thermometer, Room lights can be automated using these type of sensors
Video Link
CLICK HERE to check How sound sensor works concept can lead to various amazing projects
These were the principles behind working of IR Sensor and sound detection sensors ,if you have any points to be added to this in case if I missed any let me know in the comments section below
