By:

Xiong Lee (Missions, Systems and Test)

Objective:

The objective of this test is to be able to send data from Android OS (Java, android studio)  to the Arduino via Bluetooth. We use a simple open source code found on github to see if we can send data to the Arduino. The mission of this experiment is to move us closer to sending data from the Google tango (the Google tango is an Android OS device, therefore it uses java/Android studio) to the Arduino via Bluetooth.

Tools:

1. Android Studio
2. Arduino IDE
3. Bluetooth Module (we used the HC-06)
4. Arduino Uno / Mega
5. LED
6. Breadboard
7. Android Phone with usb cord.

LED Test Java Code:

The Java code that is on github should work when you import it to Android studio. After importing the code into android studio, you have to wait and let android studio build the project. This will take from seconds to minutes. Once the gradle has been built, you can run the app. Before you run the app, you have to make sure your android phone is in debug mode (if you don’t know how to get it to debug mode, just google it with your version of phone) so you can connect it to android studio. Once your phone is connected to android studio, you can run it and choose your phone so the app can be on your phone. When have the app on your phone, then you need to go to the Arduino code. If you want to know more about the code, I suggest that you read and run through the code yourself to get an idea of how this app works.

The sample code can be found here

LED Test Arduino Code:

The Arduino code is also on github. It is at the bottom of this page here. Just copy and paste it to Arduino ide. Once you have it, go through the code so you know where to connect everything on the Arduino. Once you have connected everything the right way, verify the code and upload it to your Arduino. (Note: There are sometimes problem uploading code to the Arduino when the Bluetooth module is connected on the Arduino at the same time it is uploading. So to get over this problem, simply just take the Bluetooth module out before uploading the code and put it back on when the code has successfully been uploaded to the Arduino.)

The first LED is connected to pin 9 and ground. The second LED is connected pin 2 and ground. The third LED is connected to pin 3 and ground. The RX on the Bluetooth module is connected to pin 11 and the TX is connected to pin 10. On the picture above, the button “Light Up” were pushed and as you can see, all the LEDs lit up.

Results:

When you have both the Java code and Arduino code, you should be able scan and find your Bluetooth module on the app. Once connected, turn on the LED lights by sliding the bars to the right or pressing all light up. Below is a picture showing how it should look like when you are lighting up the LED. In the end, we were able to send data from java to Arduino via Bluetooth. To take this a little further, we successfully move our pathfinder prototype with the app.

Changing just bits and pieces of the code, we were able to make the rover go forward, backwards, and turn. The java code that was changed was only the button name. The  main change that made our rover move was changing the Arduino code. We sent the data to the motors instead of LED.

Making the LED App Control Motors:

The main thing that we changed in this code was the serial port, and adding the motor shield code. We changed the serial port that we use to send data to the Arduino. Since we are using the Arduino Mega, we use serial port 2 instead of pins 10 and 11 as above. In the first LED case, we made the rover go forward. The second LED made our rover turn right and the third LED made it go in reverse. On the Java code side, we didn’t change anything from the code, we just changed names of LED1, LED2, and LED3 to forward and reverse.

The demo video can be found here

Moving Rover Arduino Code:

The the code highlighted below is what was changed from the code given in the link above. These code were added so we can move the motors of our pathfinder.

#include <SoftwareSerial.h>

#include <stdio.h>

#include <DualVNH5019MotorShield.h>

DualVNH5019MotorShield md;

int ledONE = 2;

int ledTWO = 9;

int ledTHREE = 4;

int bluetoothTX = 11 ;

int bluetoothRX = 10 ;

char receivedValue ;

SoftwareSerial bluetooth ( bluetoothTX, bluetoothRX );

void setup()

{

 Serial2.begin(9600);  

 Serial2.println(“console> “);

 pinMode(ledONE, OUTPUT);

 pinMode(ledTWO, OUTPUT);

 pinMode(ledTHREE, OUTPUT);

//  bluetooth.begin(115200);

//  bluetooth.print(“$$$”);

//  delay(100);

//  bluetooth.println(“U,9600,N”);

//  bluetooth.begin(9600);

}

void loop()

{

int brightness = 0;

int led = 0;

signed int data = 0;

//if( bluetooth.available() )

  if (Serial2.available())

 {

   //data = (int) bluetooth.read();

   data=(int) Serial2.read();

   Serial2.println( data );                 // for debugging, show received data

     if(data == 26)

     {

       allDown() ;

     }else if(data == 89)

     {

       allUp() ;

     }else{

     led = data / 100;                     // which led to select ?

     brightness = data % 100 ;             // 0 – 25 , LED brightness ( * 10 ) for actual value

   switch(led)                             // Now, let’s select the right led.

   {

     case 0  : setLEDthree ( brightness * 10 );  break;

     case 1  : setLEDone ( brightness * 10 );    break;

     case 2  : setLEDtwo ( brightness * 10 );    break;

     default : setLEDthree ( brightness * 10 );  break;       // DO NOT know what to do ? must be led 3

   }

     }

   //bluetooth.flush();                       // IMPORTANT clean bluetooth stream, flush stuck data

 }

}

// SHUT DOWN all leds

void allDown()

{

   digitalWrite(ledONE,  LOW ) ;

    digitalWrite(ledTWO,  LOW ) ;

     digitalWrite(ledTHREE,  LOW ) ;

}

// ALL up now 

void allUp()

{

   digitalWrite(ledONE,  HIGH) ;

    digitalWrite(ledTWO,  HIGH ) ;

    digitalWrite(ledTHREE,  HIGH ) ;

}

void setLEDone(int brighteness)            // move rover foward

{

   int m1Speed = brighteness; // left motor

 int m2Speed = brighteness ;// right motor

 md.setSpeeds(m1Speed, m2Speed);

//analogWrite(ledONE,  brighteness*16 ) ;

}

void setLEDtwo(int brighteness)     // turn rover to the right

{

      int m1Speed =  brighteness; // left motor

 int m2Speed = -brighteness ;// right motor

 md.setSpeeds(m1Speed, m2Speed);

//analogWrite(ledTWO,  brighteness*16 ) ;

}

void setLEDthree(int brighteness)   // move rover in reverse

{

     int m1Speed = -brighteness; // left motor

 int m2Speed = -brighteness ;// right motor

 md.setSpeeds(m1Speed, m2Speed);

//analogWrite(ledTHREE,  brighteness*16 ) ;

}

Conclusion:

In conclusion, we were able to send data to the Arduino from Android OS via bluetooth. We then tried to control the our motors by changing up the code to light up LEDs to control the left and right motors on the pathfinder. The next step is to implement this code to the Google tango point cloud app and see if we can extract the depth and send it to the Arduino.

Source Materials:

1. Sample code:       https://github.com/hishriTaha/AndroidLEDcontrol
2. Demo video:        https://www.youtube.com/watch?v=G-8PoH8V9-Q
3. Image:                  http://payload71.cargocollective.com/1/7/248583/3734433/amarino_905.png

by:

Tuong Vu (Electronics & Control – Sensors, Actuators and Power)

Introduction:

            This blog post will be explaining the total current drawn from the batteries by the motors. The amount of currents drawn from the batteries are resulted of the wheels experiencing at different friction forces. Different friction forces  correlated to different terrains that the pathfinder traveled on. For example, rocky  or sandy  terrains  required the pathfinder to exert more torque on its wheels in order to move which corresponds  to more current  being drawn from the batteries. The friction force is much larger on sandy or rocky terrains compare to smooth cement terrains. The  more  currents  being  drawn by the pathfinder lead to shorter batteries life (refer the previous blog post about batteries life).

Test  procedure:

Components:

• R.S.E.717 Multimeter
•  Samsung S7 cell phone
• Motors :  Pololu motors

Using  the DMM in series with the motors shield would allow currents  drawn from the batteries by the motors  to be observable.  As the pathfinder conducts its route, collecting the currents being drained from the  batteries is an issue. A smartphone was  attached in the back of the pathfinder to  record the  currents  being drawn  from the batteries as  the pathfinder goes through its route.

Current  drawn:

• Moving back and forward  do  not  require  high  amount of  pressure  on the wheels  which  current was  drawn was  the low,  refer to figure.1.

Figure 1

• Turning left and right required more than the average current drawn,so the battery life is shorter, refer to figure 2.

Figure 2

Different  load &  road environment :

Torque  is the ( N*M)  as  N is the force  and  M as  mass  of the total load. Amps is the current  drawn by  the motors. As  the  pathfinder  undergoes a  route through rocky  terrain, more torque  is required to turn its wheels.  Travelling on rocky terrain deplete the batteries much  faster than travelling on smooth surface, current drawn from the motor is linear proportional to the motor torque, refer  to figure 3.

Figure 3

Conclusion:

The amount of currents drawing from the batteries is related to the terrains that the wheels of the pathfinder travels upon. Rocky and sandy  terrains require the pathfinder to exert more torque on its wheel in order to move which corresponds  to more current  being drawn from the batteries,so turning left and right draw more current than going forward and backward.

Sources:

1. http://curriculum.vexrobotics.com/curriculum/speed-power-torque-and-dc-motors/dc-motors              DC Motors

by:

Juan Acosta (Electronics & Control – MCU Subsystem & Firmware)

Introduction:

One of our requirements is to have the Pathfinder explore the CSULB campus at night. In order for us to accomplish this objective, we will need a way of maintaining a visible line of sight for the Tango Tablet and Android Phone. So we decided that we would give the Pathfinder bright headlights that would allow us to see a maximum of 4 meters or about 12 feet ahead of the pathfinder.

Materials:

• HC-06 bluetooth Module
• Ar 2560 or Arduino UNO
• Jumper Wirduino MEGAes (4)
• 6 Piranha 5V Led Light Panel Board White Night Lights Lamp Super Bright (2)
• Laptop with Coolterm application

Fritzing Schematic and Steps:

• Wire GND of the HC-06 to GND on the arduino
• Wire VCC of the HC-06 to 5V on the arduino
• Wire RXD of the HC-06 to TX0 on the arduino
• Wire TXD of the HC-06 to RX0 on the arduino
• Wire 5V of the LEDS to PIN52 on the arduino
• Wire GND of the LEDS to GND on the arduino
• Upload arduino code provided. (Notice: Be aware that the HC-06 must be unplugged while uploading code to the arduino, otherwise you may run into functionality issues.)
• Initially you will have to pair the HC-06 with the laptop through bluetooth (Password for HC-06: 0000 or 1234)
• Manually control the LEDS through Coolterm by sending a ‘0’ for off, or ‘1’ for on.

Arduino Code:

// The following code was written, tested and debugged by Juan Acosta for

// testing the LED Headlights operation using the HC-06 to implement commands

// being sent from the COOLTERM application from a laptop or phone to the arduino.

// Group: Pathfinder Spring 2016

// Electronics and Control:  Juan Acosta (MCU Subsystem and Control Firmware)

///////////////////////////////////////////////////////////////////////////////

// following are connections required for HC06 module:

// connect BT module TX to RX0

// connect BT module RX to TX0

// connect BT Vcc to 5V, GND to GND

///////////////////////////////////////////////////////////////////////////////

// following are connections required for LED Headlights:

// connect 5V to Pin 52 of the arduino MEGA

// connect GND to GND

///////////////////////////////////////////////////////////////////////////////

void setup() {

pinMode(52,OUTPUT);       // initialize pin 52 as output for LED Headlights

Serial.begin(9600);       // set the data rate for the Serial Port

}

char a; // stores incoming character from other device (phone, tablet, or laptop)

void loop() {

if (Serial.available()){        // if text arrived in from hardware serial…

a=(Serial.read());

if (a==’1′){

digitalWrite(52,HIGH);     // turn the LED Headlights on (HIGH is the voltage level)

}

if (a==’0′){

digitalWrite(52,LOW);      // turn the LED Headlights off

}

if (a==’?’){

Serial.println(“Send ‘0’ to turn LED Headlights on”);

Serial.println(“Send ‘1’ to turn LED Headlights off”);

}

// you can add more “if” statements with other characters to add more commands

}

}

Video Demonstration

Conclusion:

We were able to meet the requirement of having a distance of at most 4 meters or 12 feet lit up. These LED lights will definitely help illuminate the path for the pathfinder as it traverses through CSULB at night. Even though these LED lights are super bright, they should not be relied on as the primary source of lighting aid, we are using these in conjunction with the lighting from all the lamp posts around campus. After we confirmed that the LED Headlights were working through bluetooth, we can then transfer what we applied over to arxterra so we can control the LED Headlights through the arxterra control panel through custom commands.

Sources:

LEDs:

http://www.ebay.com/itm/181941929073?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Coolterm:

http://freeware.the-meiers.org