Arduino Line Follower With PID and 90 Degree Turns

This is my line follower with PID and arduino.

It does 90 degree turns.

I will show you how i build it.

Have fun!

1. 2 Pololu Micro Metal Gearmotor HP 6v
2. 2 Pololu Micro Metal Gearmotor Bracket Pair - Black
3. 2 Pololu Wheel 32×7mm Pair - White
4. 1 SparkFun Motor Driver - Dual TB6612FNG (with Headers)
5. 1 QTR-8RC Reflectance Sensor Array
6. 1 Arduino Nano
7. 2 cells 7.4V 1000Ah Li-Po Battery
8. 1 Of this

9. Acrylic

10. Screws

11. Nuts
12. Foamy

Between Arduino nano and line sensors (Pololu QRT8-RC)

Its similar like in the image, but i usea another pins.

Now,

Arduino---|---Sensor

D2----------|--------8

D3----------|--------7

D4----------|--------6

D5----------|--------5

D6----------|--------4

D7----------|--------3

D8----------|--------2

D9----------|--------1

5V----------|-------Vcc(+)

Gnd(-) ----|-------Gnd(-)

The conection its similar like its shown in the image.

I varie the original circuit to fit with the arduino nano, so i use ports A's not D's.

Arduino------|-----Motor diver

D10 ----------|-----PWM A

A5------------|------IN2 A

A4 -----------|------IN1 A

A3------------|------STANDBY

A2------------|------IN1 B

A1------------|------IN2 B

D11-----------|-----PWM B

5V------------|------Vcc(+)

Gnd(-)-------|------Gnd(-)

VM its a special case, beacuse it goes to the positive (+) of the battery, like in the first image.

Its very simple,

Just follow the connections of the image and thats it.

I made it from a square of acrylic with a motor tool, you may use CNC or other techniques.

The bot have foamy to protect the sensors from the external light.

Here you can download the complete code.

I use PID derived from the theory of control.

You may ajust the values of Kd, Kp, and maybe the base motor speed.

Those values were found experimentally, so you may try diferent values.