TechieRka

Make Smartphone Controlled RC Car(with speed adjustment)!

2018-05-28T09:48:00.001-07:00

Bluetooth controlled RC Car: -
Ever thought of controlling your RC car by your smartphone? Cool, huh? Well, that’s really not a hard task to make that type of cars or bots. In fact, if you have some experiences in the field of Robotics, you would know that it is quite common to make this type of bots as they are much simpler to control (also have much better and precise control than those DPDT controlled RC bots).

So, as we proceed to further details of making such bots, I should tell you that there are mainly two variants of these smartphone-controlled bots-

1)Accelerometer controlled (You can control your bot by tilting your smartphone)

2)Key controlled (Your smartphone’s app will contain 4 arrow keys for Up, Down, Left, Right. You can control your bot by pressing those keys)

We shall show you how to make bots of both variants. Now, let’s get to the work.

Requirements: - (Product Links are given below)

1) Bluetooth Module HC05

2) Arduino UNO or Genuino UNO

3) L298N(Recommended) or L293D motor driver module

4) 2 wheeled or 4 wheeled chassis

5) Motors - 2 or 4(according to your chassis. Number of motors=Number of wheels)

6) Batteries or any other power source to run motors.

Making of Chassis: -

At first, make the robot body by assembling the robot chassis, motors, wheels and clamps (if needed).

Then if your chassis is of two wheels, add the caster and ball to your chassis and complete it.

If your chassis is of 4 wheels, connect two motors of left side with each other in same sense of rotation (i.e., they should rotate in the same clockwise or anti-clockwise direction if connected to same voltage source in parallel connection. You can easily check it and manipulate its connections if needed)

In this step, I think you should have got lots of free space on the top of your chassis. Add an Arduino, L298n motor driver (not L293d, if it is a 4-wheeler chassis. As, in practical case, we have seen L293d cannot take too much load and it does not have in-built facility of PWM and its Power efficiency is also low) and a small breadboard. Now add the Bluetooth Module HC-05 on the bot. Now, the chassis of our bot is ready.

Now, let’s get to the circuitry part.

Making Circuitry: -

Construct the circuit below.

1)Arduino GND-Battery (or other power source for driving motors)(12V) GND-L298(or L293) Motor Driver GND-Bluetooth Module GND

2)Arduino 5V-Motor Driver VCC (5V)-Enable 1-Enable 2-Bluetooth Module VCC(5V)

3)OUT 1, OUT 2-Right Motor

4)OUT 3, OUT 4-Left Motor

5)IN1- Arduino Pin 5

6)IN2- Arduino Pin 6

7)IN3- Arduino Pin 7

8)IN4- Arduino Pin 8

9)Arduino Pin 0 (RX)-TX Pin of Bluetooth Module

10)Arduino Pin 1 (TX)-RX Pin of Bluetooth Module

11)Power Source for driving motors(12 V) – Motor Source 12V Pin

Note: -

1)Some Bluetooth Modules are designed for working at 3.3 V. So, at first check this. If your Bluetooth Module is designed for working at 3.3 V, connect that VCC pin to Arduino 5V Pin through a 220-ohm resistor.

2)In circuit diagram, I have not shown the Power Sources (or Batteries). You have to add the power sources obviously. Also you have to provide 5V at EN 1 and EN 2 of Motor Driver.

Now its coding time.

Code Your Arduino: -

Upload the following codes to your Arduino. I have uploaded those Arduino codes along with a Readme file in a folder in Google Drive. You can easily download it.

Links: -

1)For Accelerometer controlled bot- https://drive.google.com/drive/folders/1sdLyPR-N9wtykOvP752-CTWoiB7OlOxH?usp=sharing
2)For Key-controlled bot- https://drive.google.com/drive/folders/1GfIu19tt-D1dJYs3-nlJfjf3X5Rq2IP1?usp=sharing

When you are done with all these stuffs, Congo! Your smartphone-controlled bot is ready to run!
If you are facing any problem with the procedure or have found any bug or mistake, please let me know in the Comments section. You can also give me your valuable suggestions for improvement of this process.

Product Links for India Only: -

Make Line-follower Robot using Arduino and IR sensor array

2018-04-12T08:08:00.000-07:00

Let sensors do the work:

Till now, we have made proximity sensor, which can be used for obstacle detection or following a black line on white surface (How and why? Ok, think about it. I will answer it a little bit later). But I want to let you people know one thing that in higher level of robotics, we don’t make sensors of our own (obviously you can make them for your hobby and interest. But DON’T USE THEM in your robots as hand-made sensors in most cases lack of accuracy and can make your robot prone to malfunction), instead we buy them in ready-made version as they are pretty much available in market in various price and accuracy range. We simply buy them and put them in our robots.

Now, as we proceed to the making of Line-follower Robot,let me answer some basic questions about Robotics.

What is a Robot?

The instruments with artificial intelligence, which follow these 3 basic rules strictly can be called "Robot".

1)A robot may not injure a human being or, through inaction, allow a human being to come to harm.

2)A robot must obey the orders given it by human beings except where such orders would conflict with the First Law.

3)A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.

These are called "The Three Laws of Robotics",devised by Science Fiction Author Isaac Asimov.

What sensors do in robotics?

What sensors do in robotics is that they make your robots smarter and recognize more activities in their surroundings and do something accordingly.

Let's make a Line-following Robot:

As, in the previous paragraph, I said you can use proximity sensor to recognize a black line on a lighter background. But, how does it do so? Actually, here when IR rays fall on black and lighter surface, black surface absorbs more IR light-rays than the lighter does and obviously reflects less amount of rays than lighter colored surface.

This makes a slight change in the voltage in the resistance connected in series with the Photodiode(for details, read about proximity sensor. Link - https://techie-rka.blogspot.in/2018/04/make-proximity-sensor-in-10-minutes.html) and we can recognize this change through calibrating our potentiometer (100k required) to an exact value of resistance. This is how proximity sensors can sense black and white surface (actually darker and brighter surface in broader sense). But, how the IR sensor array helps in following a specific line will be discussed in the Circuitry part and Coding part.

Let’s make it:

Requirements:-

1)IR sensor array of size 2(or simply 2 proximity sensors) or 3 or 5 or 8

(Links- https://amzn.to/2GO8msK , https://amzn.to/2JEbeGG , https://amzn.to/2qtis7E , https://amzn.to/2Hc0zV4(For India Only),https://amzn.to/2GR51cy(For India Only) )

2)Arduino UNO or Genuino UNO

(Links- https://amzn.to/2pV7BUa , https://amzn.to/2GL7Vig , https://amzn.to/2GLoiv3 )

3)L298N(Recommended) or L293D motor driver module

(Links- https://amzn.to/2IO5IzP , https://amzn.to/2HsVoha , https://amzn.to/2Hfbu0o , https://amzn.to/2II4UfG , https://amzn.to/2qrR0H9 )

4)2 wheeled or 4 wheeled chassis

(Links- https://amzn.to/2HvmZP2 , https://amzn.to/2qrn9P0 , https://amzn.to/2H3e72D , https://amzn.to/2E9wm3j , https://amzn.to/2JCB1ih)

5) Motors - 2 or 4(according to your chassis. Number of motors=Number of wheels)

(In many cases, when you buy chassis,you get motors in-built,so check it before buying extra motors)

6) Batteries or any other power source to run motors.
7)Digital Multimeter (to check circuit,you may need a multimeter too)
(Links- https://amzn.to/2qnSH9c , https://amzn.to/2Hdkmn8 , https://amzn.to/2HfdMg0 , https://amzn.to/2GT1Tc1 )

For testing and experiment, you may also need some white A1 paper and black tape to produce black line on white surface.

Now,let's start making:

At first, make the robot body by assembling the robot chassis, motors, wheels and clamps(if needed).

Then if your chassis is of two wheels, add the caster and ball to your chassis and complete it.

If your chassis is of 4 wheels, connect two motors of left side with each other in same sense of rotation(i.e. , they should rotate in the same clockwise or anti-clockwise direction if connected to same voltage source in parallel connection. You can easily check it and manipulate its connections if needed)

So, now ,as the body of our robot is ready, let's add sense(sensors) and brain( Microcontroller ...LOL...Don't get me wrong) to it.

In this step, I think you have got lots of free space on the top of your chassis. Add an arduino, L298n motor driver (not L293d,if its a 4-wheeler chassis. As, in practical case, we have seen L293d cannot take too much load and it does not have in-built facility of PWM and its Power efficiency is also low) and a small breadboard. Now add the IR sensor array in the front of your robot and stick with a double tape. In this case, you should ensure that the IR sensor array has got almost perfect central and horizontal alignment. Also ensure that its height from the surface is not more than 1.5 inch(otherwise it can malfunction).

Now, our chassis-making part is fully completed. Let's get to the circuitry part.

Make the following circuit.

Although the circuit diagram is quite clear, to avoid any confusion, I am listing all the connections made above in a list:

1)Arduino GND-Battery(or other power source for driving motors)(12V) GND-L298(or L293) Motor Driver GND

2)Arduino 5V-Motor Driver VCC-Enable 1- Enable 2

3)OUT 1,OUT 2-Right Motor

4)OUT 3,OUT 4-Left Motor

5)IN1-11

6)IN2-10

7)IN3-6

8)IN4-5

When you're done with all these stuffs, proceed to the coding part. Only this coding part will be different for IR sensor array of size 8,5 and 2. When you will opened the code, you will find the Pin numbers are given for IR sensor array. Connect the IR sensor array strictly according to that. Also here, I am giving the details for connecting the IR sensor array.

For IR sensor array of size 8:

The pins are: {A0,A1,A2,A3,A4,A5,8,9} (Aligned from left to right)

For IR sensor array of size 5:

The pins are: {A0,A1,A2,A3,A4} (Aligned from left to right)
For IR sensor array of size 3:
The pins are: {A0,A1,A2}

For IR sensor array of size 2:

The pins are: {A0,A1} (Aligned from left to right)

So, finally we have completed the circuitry.

Now, let’s talk about the logic of the bot and after that we shall move to the coding part.

Understanding the logic:

So, now we know, by the IR sensor array, we can recognize black and white line, which also implies that we can detect the position of black line with respect to the bot. So, now we have to think about various possible positions of black line with respect to the bot and what our bot should do at those situations.

Now, there is slight difference of logic for Bot with IR sensor array of size 8 or 5 or 3 and Bot with 2 IR sensors. When the Bot is on the top of the black line symmetrically or in centrally aligned position, for bot with 2 IR sensors, each sensor should sense white, while for the bots with IR sensor array of size 8 and 5,only the central portion of the array sense black and rest of the sensors sense white.

Position 1:

In this case, Robot is almost on the top of the black line symmetrically, so here the bot should go ahead straight.

Position 2:

In this case, the left portion of IR sensor array should sense black, while the right portion should sense white. In this case, the bot should take a left turn to adjust its position with respect to the black line.

Position 3:

In this case, the right portion of IR sensor array should sense black, while the left portion should sense white. In this case, the bot should take a right turn to adjust its position with respect to the black line.

These were 3 basic positions for the bot. Now, we should consider some more consequences:

1)What if the bot has moved away from the line, i.e., each sensor senses white? In this case, we move our bot backwards in expectation to get the black line again.

2)What if it has struck a T-shaped joint or cross joint, i.e., all sensors sense black? In this case ,we can move our bot in either left or right position.

Let's code it:

Now, let’s move to the coding part. On the basis of the logic above, I have made three Arduino codes for your bot. They can work with both 4 wheeled and 2 wheeled chassis and with both L293D Motor Driver and L298N Motor Driver.

I have uploaded that Arduino codes in a folder in Google Drive. You can easily download it.

Here is the link: https://drive.google.com/drive/folders/1TXzQ_Tl1bcGthja30UfEkEzw3Tack2Zd?usp=sharing
For those who are facing problem with Google Drive can download the files from this link too.
Link: http://www.mediafire.com/file/9ts45rdn4hgou0t/Line_follower_Robot%28Techie-rka.blogspot.in%29.zip

So, now as you have uploaded the code to your Arduino, you have to calibrate your IR sensor array by adjusting each potentiometer to detect black and white line. Once, you’re done with this, you have completed making of the Line-follower Bot. Congratulations!!!

If you like this post, please upvote, comment, follow, share and subscribe. Thanks in advance.

Make Proximity Sensor in 10 minutes!!!

2018-04-03T04:57:00.001-07:00

Make Proximity Sensor in 10 minutes:

At first we must know, What is a proximity sensor?

It is basically a sensor which detects if any object is within some distance or not and gives us alert accordingly. Although it may seem tough,its working principle is not that much hard. So, let us now learn how it works.

Working Principle of Proximity Sensor: (Optional yet Recommended)

There are various types of proximity sensors (like an Ultrasonic distance Sensor can easily be converted into a proximity sensor. Also we can use IR LED and IR Receiver pair or a visible light LED and LDR pair to make proximity sensor etc). Here we shall make Proximity Sensor by using IR LED and IR receiver.

So, how it works?

Basically, an IR LED is used to transmit IR rays and an IR receiver is placed near the LED (obviously not facing the LED). So, when an object is present over the LED, the IR rays are reflected by the obstacle and comes to the IR Receiver. When IR rays struck the IR Receiver (which is basically a Photodiode or a Phototransistor), its resistance decreases significantly in reverse biased mode, which in turn causes a change of voltage in an external resistor. A voltage comparator IC can easily detect this voltage-change and send alert accordingly.

How to make it:

Required Materials:

Collect the required materials listed below from the links given or local store(More preferred because you can buy those items at lower cost at your nearby Electronics Store than the online links).Also you can buy a basic kit for robotics from the link below,which will be much cheaper and you will get much more things in your hand.

1)LM 358 IC(or any other op-amp such as IC 741 etc)(Here,we shall use LM 358 IC)

( https://amzn.to/2IoPSLQ )

2)1 IR LED and 1 IR Reciever(Photodiode)( https://amzn.to/2IpJOCQ )

3)Resistors :-

270 ohm – 2 pieces

10k ohm – 1 piece

4)Potentiometer (10k or 100k)

5)Power Source (3 – 12 volt)

6)Breadboard

7)Jumper Wires(preferred) or single stranded wire

8)Visible Light LED and a buzzer(optional)

You can buy those items loose or you can buy a complete robotic kit set from the below link:

1) https://amzn.to/2EgHf3o

2) https://amzn.to/2EfWvh8

IF YOU ARE FROM INDIA,then following link is more beneficial for you: https://amzn.to/2GtpnIx

Now as you have gathered all the required materials, make the circuit below in your breadboard strictly following the circuit diagram below.

Circuit Diagram:

Here I am adding Pinout diagram of LM358 IC too.

For those who are working with ICs first time,the pins of an IC are numbered anti-clockwise around the IC(chip) starting near the notch or dot. The diagram shows the numbering for an 8-pin IC, but the principle is same for all ICs.

NOTE:- If you want to improve your sensor’s sensitivity further, you can put three more IR LEDs to cover all four directions of the IR Receiver. You will have to connect the other three LEDs in parallel connection with the first IR LED.

Also,you can add a buzzer to create a buzzing sound when an obstacle is placed in proximity to the sensor.You will have to add that buzzer in parallel connection to that visible light LED.

Congrats,you have made your own Proximity Sensor.In case of any query or problem or suggestion or feedback , tell me in comment box.Hope,you guys enjoyed making it.

Just give a start

2018-04-01T13:27:00.000-07:00

Guys,before we get to work,I think you should buy some of these basic Robotics materials:

1)Arduino UNO Kit(https://amzn.to/2pV7BUa or https://amzn.to/2GL7Vig or https://amzn.to/2GLoiv3 )

2)Robot chassis with 2 or 4 wheels( https://amzn.to/2E9wm3j or https://amzn.to/2H3e72D )

You can also buy and read this book on making mind controlled bot(Book name-"Make a Mind Controlled Arduino Robot (Creating With Microcontrollers Eeg, Sensors, and Motors)“ by O’Reilly).I swear this is interesting and you will like it.Link- https://amzn.to/2uBElXF (For India only)

The above links are available globally.For India,there are some special links also:

1)Arduino UNO Kit(https://amzn.to/2Gt23qy or https://amzn.to/2uCMhHU or https://amzn.to/2uDSL9p (best))

2)Robot chassis with 2 or 4 wheels( https://amzn.to/2GpJWSd or https://amzn.to/2J9t9Vm )

Welcome to Techie-Rka

2018-04-01T13:25:00.001-07:00

Hey,welcome to Techie RKA.In my blog,you will find various interesting facts,ideas about Robotics.My posts will be about Robotics projects,some coding facts and tricks etc....Hope you guys will enjoy it..