Introduction: Simple Easy Diy Light Following Robot Without Micro Controller. (anybody Can Make ROBOT)

About: A Computer Science and Engineering student and a Hobbyist. love to make robots,electric devices,diy things and Programming them by Myself. My youtube channel Follow me on gi…

As the name offers this Robot finds brighter light source and automatically Goes to the bright light source. Yes you won't need to program it. If your're new to robotics and afraid of programming then this is the robot you can make as your 1st robot. Also if you're willing to make Arduino robots then you must make basic robots like this one as you must know the basic. The great thing about this robot is it only uses two components. LDR and TRANSISTOR.

Let's get started.

Step 1: Parts:

1. BC337 / 2n2222 npn transistor 2x *

2. LDR (photo-resistor) 2x *

3.Gear motor 2x

4. Wheel 2x (compatible with the motor)

5. Rotary wheel or ball Caster [3rd wheel] (i recommend ball caster,rotary caster makes false moves)

6. Male pins (optional)

7. AAA battery 4x / 6v power supply. (7.4v is okay too)

8. Vero board or cardboard for body.

9. Battery holder.

*things are must. Other things can be used anything you want. I've used old toy parts mostly. You can buy from online store too.

Buy electric components on

Step 2: Principle:

The Light Following Robot's working principle is called as PHOTO-TAXIS. Photo means Light, The robot moves towards the brightest light source. It uses two LDR (photo resistors) and two transistors - one for each motor. When light falls on LDR's the circuits resistance drops down and through the Transistor approx. 1Amp current flows thus the motors rotate and the robot moves.

NB: Use left LDR for Right motor // & // Right LDR for Left Motor. ********

So, if light comes from Right side the Left motor will be on- the robot will take Right turn.

& if light comes from Left side the Right motor will be on- the robot will take Left turn.

If both the LDR's get Light the robot will move forward,else it stops.

To be clear watch the video (full video tutorial)

Step 3: Build the Body of the Robot

I've built the robot using simple techniques. I've used a veroboard as chassis. Then attached the motors using Double sided tape. I've used old toy's wheels rather than buying some. You may also buy chassis from online.just google it. But its cheaper making at home ,specially for basic robots.

Step 4: Build the Simple Circuit

Circuit is damn too easy. You may make it by the schematic or the Fritzing circuit. Take a piece of veroboard and solder all the components on that carefully. Keep the LDR's leg longer as they'll work as antena to see light (see image 4 or 5). Please keep in mind that the left sensor will control right motor,and right sensor will control left motor. after finishing, It should look something like this in picture four and five.

Step 5: Add Sensor to the Body

Then add the sensor on the robots body using glue or double sided tape. Connect right motor to left sensor and left motor to right sensor. power it up using 4 AAA / AA cells or 3 to 7.4v power supply. From my experience though 6v is better.

Don't worry if the motors turn in opposite directions,just swap the wire of the motor and it'll be okay. And yes the transistors may get warm or sometimes hot, it's ok too. But dont let them be too hot.

Step 6: Finished

That's it and you're Done making your 1st robot. Connect with battery and play with it with a torch light or any light source.

You may also watch this video tutorial

It's my 1st ever instructable. Pardon my mistakes. Thanks.

[NB: This robot is for INDOOR only. As the daylight is the most powerful light source the robot will continiously move with a bit of sunlight. But can be taken out at Night when the Sun isn't there.]

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