IR Based Line Following Robot From Scratch [No Microcontroller]
Introduction: IR Based Line Following Robot From Scratch [No Microcontroller]
In this instructable we'll use the concept, reflection of infrared radiation to built a circuit which can detect the difference between black and white coloured surface. That might not sound interesting but later we can use that circuit to build a robot which will follow a black line, and the best part is, the whole build is purely based on electronics and no programming or coding is required! If you are getting started with electronics or getting a concept of science into a project this would be a great place to start. So, grab the components mentioned below and get started with the instructable.
Supplies
These are the list of products which can help you do this project with ease
(Affiliate Link)
* Resistor Kit : https://amzn.to/3frj4nx
* IR module : https://amzn.to/3yVvGfM
* Potentiometer Kit : https://amzn.to/3wxfoaS
* IR LED Pairs : https://amzn.to/3fVzhl4
* Red LED : https://amzn.to/3hZgJDe
* PCB : https://amzn.to/2TfaTmP
* BO motors & Wheels : https://amzn.to/2RKn9M1
* Copper Clad : https://amzn.to/3vxsHIj
* L293D IC : https://amzn.to/34sy5AC
* Caster wheel (alternative) : https://amzn.to/3fVCQaW
* Capacitors : https://amzn.to/3c2vUrv
* Header pins : https://amzn.to/3wG0wXL
* Lithium Battery with charger : https://amzn.to/3wGSRbw
Step 1: Infrared Radiation
Light is a complicated topic in physics because of it's dual nature where it act as both particle and wave at the same time. To understand how this project works will just stick on to our pal Maxwell and consider light as electromagnetic waves! These waves consists of several wavelength starting from from the shortest wavelength Gamma waves to the longest wavelength Radio Waves . The most common electromagnetic waves that everybody experience in day to day life is from 380nm to 740nm A.K.A “the visible region” or "the visible light".
Similarly, Infrared Radiation is part of the electromagnetic spectrum with the wavelength of 700nm to 1mm. infrared radiation has slightly longer wavelength than the visible light therefore this radiation is invisible to human eye but can be caught on most of the camera.
[Note : Infrared radiation also obeys all the laws of reflection and the laws of refraction just like the visible light]
Step 2: Source of IR Radiation
Sun is major source of electromagnetic radiation but most physical body emit some sort of radiation based on there property like nuclear radiation by nuclear substances (Gamma waves), heat produced by human body (infrared radiation), etc. Infrared radiation is produced by all the physical object which have temperature more than absolute zero or -273k(approx.). But the magnitude of infrared radiation produced is very small so, the IR detector which we use in this project cannot capture them. 33
Therefore we will have to use an IR emitting LED which emit infrared radiation with greater intensity. There are two types IR LED narrow band and a wide band. In this instructable we'll use a narrow band IR emitting LED and in later steps we'll see the reason, why we chose this.
Step 3: Formation of Colour
Between 380nm to 740nm we have visible light, this visible light is further divided into different colours based on the wavelength [eg : Green - 590nm to 635nm]. When all these colours is removed form the spectrum it becomes dark/black because our eyes don't receive any input and combining all the colours in the spectrum we perceive the colour white. By now the concept of colour makes sense in electromagnetic waves but the interesting question to ask is... what makes the physical object like plant Green? and apple Red?
Every object absorb and transmit light in some or the other way. When the light strikes the surface of the object, different wavelength of light get absorbed depending on the molecular composition of the physical object. So whatever colour we see is just the reflected wavelength of the light which is not absorbed by the object. In the same context we see the colour white because of reflection of the all the wavelength of light that wasn't absorbed by the body and finally black is due to absorption of all the wavelength of the light (Even though we don't see Infrared radiation the concept of absorption and reflection remains exactly the same). 970