Wednesday, 30 August 2017


The line follower can be divided into 3 subparts.
They are-
1. Sensors
2. Motor and Driver
3. Microcontroller
In this blog only sensors will be discussed.


Sensor is like an eye for line following robot and through this digital signal is fed to the arduino.
Sensor are of two kinds-
1. Analog (gives signal between the value 0-1023 for 0-5V input)
2. Digital (gives signal of either 0 or 1)

Digital sensors are prefered because of better sensitivity and lesser programming. The components of digital sensors are
1. IR Sender and Receiver
2. LM358 IC 2 IR transmitter and receiver pair
3. Resistors of the range of kilo ohms
4. Variable resistors.
5. LED (Light Emitting Diode).
6. PCBs and soldering Equipments 

When the ir rays from ir sender are reflected from the object and fall on the IR receiver, it changes its state of open to close, behaving as a switch.
It offers minimum resistance when ir rays fall on it.


The abbreviation LM358 indicates an 8-pin integrated circuit, comprising two operational amplifiers at low power. The LM358 is designed for general use as amplifiers, high-pass filters, low band pass filters, and analog adders.

It is used as a comparator here. It compares between the reference 
voltage with the signal from the ir receiver, if signal is greater than reference then out put will be 1 or digital HIGH. else it will be 0 or digital LOW.

If you are interested of building one sensor at your own. but its better to buy these.
These can be of one sensor or sensor array

It's better to use multiple sensors for better accuracy. You will atleast need 2 single sensor for operation. SIX sensor are better if you are using arduino UNO,you can connect them in analog pins.
If you are using MEGA no pin nos is concerned.

The distance sensing capability can be adjusted by using the potentiometer spinning it in appropriate direction.Any sensor module must have a VCC+ and GND- pin with them and output pins of equal numbers of sensors. 5V supply to the sensor is quite good for the operation. If you are using separate source for sensor you should make the ground common with arduino's ground.

Thanks for reading my blog........

Friday, 25 August 2017

How to burnt Arduino and repaired it.

It is quite harsh and sad if your arduino stops working. It a heart breaking experience because it's your project's heart. I am discussing how one can burnt arduino.
Can it be repairable !!! Yes or No?? and if yes HOW!!!

How to break/burn/damage Arduino.

1. Overvoltage 

Though arduino have voltage regulator it works between 5-20V and 7-12 V be the desirable ones. Giving more than that is risky.

2. Shorting Input/output pins or overvoltage them.

     I was once working with a motor driver circuit and one of 12v terminal got connected with input and that damage the AtMega328 IC. Later I was able to replace that one and made my arduino work again.From my experience I suggest that you never short you input or put high volts through them.

3. Unwanted connections

     Recently I damaged my arduino by an unconventional way that is unrepairable. I had a open wire of 12v that came contact with 6pins of FDTI (don't know particular).So this result in damaging the FDTI permanently and the arduino board is shorted. Atmega chip was damaged and when I tried replacing it with another chip....I lost both of them. I have no idea how to repair.

4. Over load operations 

     Another case its not damaged actually,it happen when u tried to switch on and after working a bit it stop suddenly. It may be the supply isn't up to the demand of load connected to arduino. This can be resolved using power source having more ampere power.

So up above are the cases one can damage arduino. Now its repairing time.
Make sure if it is repairable...
First remove the atmega chip from board. For nano,mega and other non removable chip users...RIP...
For UNO users remove it. Then plug it up and see if the led of rx/tx and pin-13 blink once or more. If yes then your board is healthy. Replace the Atmega chip with new one with arduino UNO bootloader. It is available in online shopping sites. Most of the Atmega 328 used in arduino comes with uno bootloader. If you can't get a chip I can help you in later blog if I have any requests.
If the leds don't blink, or stays on..your board is damaged... RIP...
Hope You liked it. Like my blog.
"Never lose hope when you fail, those who don't fail haven't tried anything new."

Sunday, 20 August 2017

Portable emergency mobile charger

Portable emergency mobile charger

KISS is a better way to build things. I mean Keep It Simple Stupid(KISS). In this post I will build a simple Mobile charger using a DC geared motor.

Things you needed:

1. DC geared motor(100 or 150 rpm)
2. 5V voltage regulator(7805 IC)
3. USB female connector

Tools: soldering things, hot glue gun, wires, plastic case


When the shaft of dc motor is rotated at suitable speed it generate about 5-12 V. The voltage regulator here works as constant voltage source to mobile device as mobile and many other electronic devices run at contant 5V DC. So any unwanted higher value is cut off by 7805 IC.


1. make the connections
2. make place for the motor
3. make place for usb_female and stick it with hot glue.

4. build a handle for rotating the shaft
5. Finally bring all together and test if your phone charges.

Thank you for reading this blog. Hope you have enjoyed it.