Played with wireless remote controlled cars right from childhood right??? Well even if you don't you will build it now.It's rather simple and not much complicated. Remote control is your smartphone itself and I have also included a camera feature so that user can see what's in front of the car!!! I developed this so that everyone can build their own car with a very few amount of money!!!
Now you are very familiar with arduino now-a-days. using arduino as brains of the project is rather easy and simple. And for the wireless connectivity we would use the Bluetooth communication. So I have developed the tutorial with complete steps and pics. So let's get started...
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Step 1: Parts List
1 Arduino UNO/Nano/micro/Mega
2 HC05 Bluetooth module
3 4.7kohm, 2.2kohm resistors
4 Breadboard or solder kits
6 chassis for the car
7 castor wheel 1pc
8 2 150/300rpm BO motor with 2 wheels
10 12V power source
11 some screws and nuts
12 2 smartphones
Step 2: Building the Circuit on Breadboard and Setup Chassis
Now Arduino nano is the brains of the project. And I would use Bluetooth connectivity feature for controlling the car with smartphone.
So I have provided the circuit in the Fritzing File.Download Fritzing and open it and see the file. Connect as shown in the diagram. Use the voltage divider as given with 2.2k and 4.7k .
Now the yellow wires(as per that fritzing file) represent the 4 output that would control the motor driver. Those 4 logic levels actually are the inputs of the motor driver and the motor driver uses that logic levels to move as per the logic levels are fed. And the arduino controls that.....means that it enables the driver to move both motors forward or backward or reverse or move right or left or just stop. This is accomplished in the code.
So see the diagrams above and then connect the motor driver inputs. Then connect the motors at the output witha couple of screws and fix the wheels . I have connected my L293 driver as per it's connection. Check your own driver, search over the net and datasheets and connect as per required.
Fix the motors with screws and fix the motor driver and breadboard with double sided tapes or simple tape. Also fix the castor wheel.See pic. Your chassis can be different so check it carefully.Attach wheels.
Step 3: About the Car Control
Now about the Bluetooth control...
The smartphone and the HC05 will be connected to each other using the bluetooth connectivity. I have developed the app using MIT app inventor tool ( Link - http://appinventor.mit.edu/explore/ ).I have attached the apk in the upcoming steps.
The app has 5 buttons - Straight, Turn Left, Turn Right, reverse,Stop .Actually the app sends ascii values when a button is pressed via bluetooth. Now the HC05 accepts that ascii values. So now we can control the motor driver as per it receives the signal. I have used them for making the app and also written the arduino code as per the value received. You will get more familiar as you start using that MIT app inventor tool.
Now the Bluetooth RX pin accept 3.3V logic levels but Nano/Uno sends 5V . So I have used voltage divider in the circuit.
Step 4: Building a Structure for Holding the Camera(mobile)
Now for the camera feature I actually put another smartphone in the space(refer to the picture).
I have old parts laying around so I used them and fixed this with the chassis. Even if you don't have these, you can make our own structure that can hold the phone.
Step 5: Upload Code and Attaching Power Supply
Now I have uploaded the arduino code here. You can download it.
Now while uploading it...make sure you have disconnected the RX TX lines. It won't be uploaded otherwise.
After uploading connect them again.
Now connect a 12V power source .A block diagram is in the picture.
Step 6: Connecting With Bluetooth and the Camera Feature
Now take another smartphones and install IMO app on both the mobiles. It is free over playstore Link-https://play.google.com/store/apps/details?id=com.... >install and open accounts on both the smartphones. It is free. Now start video call over both phones.Now put one mobile in the socket you just build on the chassis.
Now minimize the app in your other phone ,in which you will be installing my app . It will run still and it will be shown in a small window in the corner of your screen.You can drag it as well. See my screenshot given.
Now install the app given. The screenshots of the app are given. Now first power up the whole thing and you should see the HC05's light blinking fast , Now open bluetooth in your phone and open the app and connect with the HC05 first( for first time use 1234 or 0000 as pairing code).Now if connected the light should blink slow ,if not try connecting again.
Now press any of the buttons. Your car should move now.If not... see connections again and re-pair your HC05.
So now your car is ready and your camera feature is also done.As you drive the video chat is on and you can see what is in front of the car!!!