I finished my final project! For my final project, I  created my own Bluetooth controller using NRF connecting my to my robot tank. Firstly, I proceeded to get a Nano which is a smaller version of an arduino so that I can have a small controller and have , being the brain of the controller. I then used two NRF’s  to connect to my Arduino Uno and Nano so that I can secure a Bluetooth connection. I soldered row of pins onto the Nano so I can then help connect my Nano to the NRF and with the help of How to Mechatronics,  I connected the NRF’s to the Arduino and Nano. An NRF helps facilitate a bluetooth connection through sending signals at certain frequencies.

Flow chart of code for receiver and transmitter

I started to rewire my pins for the motors because my NRF required certain pins. This resulted in me changing some of my code. Using a sample code from the website above, I attempted to send messages to my receiver from the transmitter.

The system works in the following manner:

1. The Nano transmitter listens to a button press
2. Nano transmitter NRF sends button press to Uno receiver NRF
3. The Arduino reads which button is pressed and moves

This at first wasn’t hard at all but I had to constantly rewire and change the ports when uploading the code to the Nano and the Arduino. I experimented with sending messages between the NRF’s to make sure I knew it worked. After successful sending “Yo its Duly”, it all of a sudden stopped working but after another student started claiming that “Yo its Duly” started to print in her serial monitor, my instructor recommended me to change my frequency so I would not interfere with any of my peer’s projects. Add a picture somewhere before this or reference the pictures you do have somewhere before this just to draw attention to the graphic. After that I started on developing my board where my prototype controller will sit and where i will control the direction in which the tank moved and its speed. I started with adding four buttons which have different colors so I can differentiate each button from each other. I then started to add pins for the Nano onto board where the pins of the buttons were connected to , so I can control the Nano to my board. I continued and connected both of the grounds of the bread board  together so that there was an imbalance of voltage. Using 4 800 ohm  resistors, it secured a zero voltage board when the board is not in use. My main focus after that was to connect my buttons to Nano to Arduino. Since buttons are basically switches, either on or off, I used booleans so I can define and function the pins, therefore controlling what the button says or does  when pressed. I was able to make my Nano print either 1,10,100,1000 for each button when it was pressed onto the serial monitor and print that onto my receiver, allowing my buttons to control what is printed. I defined the colored buttons as forward for red, blue for backward, yellow for left and black for red. I then put my code for my directions onto the receiver and  coded a series of if statements stating whether if a button is pressed and the others aren’t then it will move.

The robot tank with an off switch

The H-Bridge in the L298n

//The directions in which the motors go
int in1 = 9; //Declaring the pins where in1 in2 from the driver are wired 
int in2 = 0;//was 8, dark blue wire //here they are wired with D9 and D8 from Arduino
int ConA = 10;//was 10, yellow wire with green writing
int in3 = 1;//was 13, purple wire
int in4 = 2;//was 12, dark green wire
int ConB = 5;//Was 11, orange wire
//And we add the pin to control the speed after we remove its jumper 
//Make sure it's connected to a pin that can deliver a PWM signal
void setup() {
pinMode(in1, OUTPUT); //Declaring the pin modes, obviously they're outputs
pinMode(in2, OUTPUT);
pinMode(ConA, OUTPUT);
pinMode(in3, OUTPUT);
pinMode(in4, OUTPUT);
pinMode(ConB, OUTPUT);
}
void TurnOFFA(){
digitalWrite(in1, LOW);
digitalWrite(in2, LOW);
analogWrite(ConA,0);
}
void TurnOFFB(){
digitalWrite(in3, LOW);
digitalWrite(in4, LOW);
analogWrite(ConB,0);
}
//Forward
void Forward(){
digitalWrite(in1, LOW);
digitalWrite(in2, HIGH);
digitalWrite(in3, LOW);
digitalWrite(in4, HIGH);
analogWrite(ConA,150);
analogWrite(ConB,150);
delay(4000);
TurnOFFA();
//delay(2000);
TurnOFFB();
delay(2000);
}

//Backward
void Backward(){
digitalWrite(in1, HIGH);
digitalWrite(in2, LOW);
digitalWrite(in3, HIGH);
digitalWrite(in4, LOW);
analogWrite(ConA,150);
analogWrite(ConB,150);
delay(4000);
TurnOFFA();
//delay(2000);
TurnOFFB();
delay(4000);
}


//Right
void Right(){
digitalWrite(in1, LOW);
digitalWrite(in2, HIGH);
analogWrite(ConA,150);
digitalWrite(in3, HIGH);
digitalWrite(in4, LOW);
analogWrite(ConB,150);
delay(4000);
TurnOFFA();
//delay(2000);
TurnOFFB();
delay(4000);

}
//Left
void Left(){
digitalWrite(in1, HIGH);
digitalWrite(in2, LOW);
analogWrite(ConA,150);
digitalWrite(in3, LOW);
digitalWrite(in4, HIGH);
analogWrite(ConB,150);
delay(4000);
TurnOFFA();
//delay(2000);
TurnOFFB();
delay(4000);

}
void loop(){
Forward();
delay(1000);
Backward();
delay(1000);
Right();
delay(1000);
Left();
delay(1000);


}

I started my 3rd milestone with assembling the gearbox holding the motors and allowing gears to turn. I watched a video on youtube about assembling it, at first everything seemed pretty difficult but taking everything slow and step by step, made things much easier and smooth. Constant problems with assembling the gearbox were having to rebuild it, due to parts being loose and always falling apart. Also, having to push the boxes together so they’re held in place and won’t fall apart and having to continuously to unscrew and screw the parts together. Then I started to assemble the universal plate where I had to mount nuts and bolts onto the plate so that the wheels are held in place. However just like the gearbox I had to constantly assemble and dismember the whole plate numerous times. Adding the wheels was very easy and took little to no time. I then proceeded to saw and file off 2 2 small parts of the plate so that I can screw down my gearbox and mount it. After that, I built my tracks allowing my tank to move as the motors turned. With the help of velcro I was able to add the battery pack, arduino and L298N motor shield on to the plate and balance all the weight so that once side of the tank is heavier than the other. Having some extra time I was able to build an off and on switch connecting my arduino, battery pack and my motors together so I could easily turn everything on when I wanted to, not depending on the power cord constantly. 

The wiring for one motor

The Arduino connected to L298N, connected to the battery and the motors

The H-Bridge in the L298n

For my second milestone , I programmed two motors to go forward, backward, turn left, and turn right. At first, I connected my Arduino to my L298n with male jumper wires. L298n is a motor shield that helps control the speed and the direction of the motors. The L298 has a H-Bridge which is an electronic circuit which switches the polarity of a voltage applied to a load, controlling the motion and the direction of the motors. In order for the motors to move forward I would have to close A and D switches and for reverse you would have to close B and C. I then connected black and red male jumper wires from the L298n to the 2000mah battery with  two red and black male cords powering the board. After that I connected female jumper wires from the L298n to the actual motors, and soldered them. Through connecting my Arduino to my computer I programmed some code, creating functions and loops, instructing my motors to move in the direction I proposed. In my functions I defined the directions in which the motors should turn, for forward, backward, right and left. Then I created loops, creating a continuous pattern I wanted it to go. This milestone wasn’t as challenging as I thought it was going to be but one minor problem is that my ps2 controller no longer works so now I have to make my own controller which will be pretty cool.  My 3rd milestone is quite easy and I expect to start it as soon as possible and hopefully finish it

The wiring for one motor

In order for this to work, you have to connect wires from the receiver to the arduino using copper wires or male to female wires. The wires help facilitate a electrical connection between the receiver and the arduino. With a power cable I connected the arduino to my laptop, allowing me to access arduino and make sure that there was a connection between both the receiver and the arduino present. Through programming code, I was able to use the buttons and the joysticks, to print out some messages when interacting with the controller. The code I used in my arduino told me when a button was pressed, when it was held, released, when I changed buttons,the pressure in which I held the buttons and the joystick values.

How it works

The Simon Says Project including the buttons, the batteries and the on and off switches

Simon Says Game

Simon Says Robot displaying the piezo buzzer and the micro controllerImage Source: https://github.com/adafruit/Adafruit-MiniPOV4-Kit/tree/master/Hardware