ee319 project report albert

Dublin City University

EE319 – Electromechanical Systems

Mini-Project Report 2015

A.L.B.E.R.T

Student Name(s) Student ID Programme

Diarmuid Kelleher

13447892

ME

David Gallagher

xx

ECE

Chris Holmes

xx

ECE

Group Number 13

Date 08/12/2015

Contents Design Brief: ..................................................................................................................................................................... 3

Equipment and Procedure: ................................................................................................................................................ 3

Equipment: .................................................................................................................................................................... 3

i. 2WD Mobile Platform ...................................................................................................................................... 3

ii. IR Distance Measuring Sensor .......................................................................................................................... 3

iii. SN754410 H-Bridge ..................................................................................................................................... 3

iv. Arduino Uno ................................................................................................................................................. 3

v. Analogue joystick ............................................................................................................................................. 4

vi. DPDT Switch ................................................................................................................................................ 4

Procedure: ..................................................................................................................................................................... 4

i. Week 7: Building of robot platform and test motors and IR sensor ................................................................. 4

ii. Week 8: Tested the servo and sensor combined ............................................................................................... 4

iii. Week 9: Assembled the entire robot ............................................................................................................. 4

iv. Week 10: Added our unique feature ............................................................................................................. 5

v. Week 11: Made presentation and report ........................................................................................................... 5

Unique Aspect: .................................................................................................................................................................. 5

2 modes: ........................................................................................................................................................................ 5

Automated decision making: ........................................................................................................................................ 5

Manual control using a PlayStation1 joystick:.............................................................................................................. 6

Code: ................................................................................................................................................................................. 7

Final Product: .................................................................................................................................................................. 10

ALBERT: .................................................................................................................................................................... 10

Pre-Tidy: ..................................................................................................................................................................... 10

Post-Tidy: .................................................................................................................................................................... 11

Problems: ........................................................................................................................................................................ 13

No Common Ground ................................................................................................................................................... 13

Broken IR sensor ......................................................................................................................................................... 13

Constant Definition in Motor Code ............................................................................................................................ 13

What we learned: ............................................................................................................................................................ 14

Step-by-step analysis is key to efficiency: .................................................................................................................. 14

Things don’t “just happen”: ........................................................................................................................................ 14

That despite its “single loop” framework, the Arduino is a powerful tool in engineering: ........................................ 14

Recommendations: .......................................................................................................................................................... 14

Mini-Project Structure: ............................................................................................................................................... 14

Team Allocation ...................................................................................................................................................... 14

Arduino Tutorial ..................................................................................................................................................... 14

Recommendations for participating students: ............................................................................................................. 14

Keep organized ....................................................................................................................................................... 14

Work on each part separately .................................................................................................................................. 14

Design Brief:

The design brief was as follows:

Design and build an Arduino controlled device

Use an IR sensor and servo motor to collision detect

Interface with Arduino to control drive motor speeds and rotation directions

Introduce a unique aspect to your device

Equipment and Procedure:

Equipment:

i. 2WD Mobile Platform

The two wheel drive robot used in this project ca be controlled by a number of microcontrollers including the Arduino

platform. There is a large amount of sample code and sample circuits available online that can be used with the

Arduino and the two wheel drive robot. The motors are mounted to an aluminum alloy body. The setup of the motors

allow a near zero turning radius.

Complete Machine weight: 445g

Wheel Diameter: 65mm

Max speed: 61cm/s

ii. IR Distance Measuring Sensor

Model used: Sharp GP2Y0A02YK0F

This IR distance measuring sensor has a measuring range of 20 to 150 cm and outputs an analogue output. The sensor

consists of a combination of a position sensitive detector, an infrared emitting diode and a processing circuit. The

device outputs a voltage that corresponds to the distance being measured.

Size: 299.5x13x21.6mm

Consumption current: 33mA

Supply voltage: 4.5 to 5.5 V

iii. SN754410 H-Bridge

The SN74410 H-Bridge a quadruple high-current half-h driver which is used to drive the 2 high-speed motors. The

device provides bidirectional drive currents up to 1 A at voltages from 4.5 V to 36 V.

Recommended operating conditions MIN MAX UNIT

Output supply voltage ,Vcc1 4.5 5.5 V

Output supply voltage ,Vcc2 4.5 36 V

High-level input voltage, Vih 2 5.5 V

Low-level input voltage, Vil 0.3 0.8 V

iv. Arduino Uno

The Uno is a microcontroller board that has 14 digital input/output pins, 6 analogue inputs, a 15MHz quartz crystal, a

USB connection, a power jack and a reset button. It is an extremely adaptable and diverse microcontroller. If

something goes wrong, the chip can be replaced for very little. This is what makes the Arduino Uno such a popular

device. There is a massive library of Arduino code and sample projects that use the Arduino boards online.

Operating Voltage 5V

Input Voltage (recommended) 7-12V

Digital I/O Pins 14

PWM Digital I/O Pins 6

Analog Input Pins 6

Flash memory 32KB

SRAM 2KB

EEPROM 1KB

Clock speed 16MHz

v. Analogue joystick

The analogue joystick was taken form a PlayStation1 controller. These were very accurate and simple to hook up, due

to the fact that the 2 potentiometers (One for Xaxis the other for Yaxis) and their circuitry was built into the unit, and

as such no additional circuitry was required to extrapolate values from the potentiometer. The joystick requires a 3V

power supply and outputs analogue values 0-660 representing the X|Y position of the joystick.

vi. DPDT Switch

Scavenged from a 1st Year Electronics Kit, this was used to switch between modes. Its 2 positions allowed the Arduino

to decide as to whether it was receiving a HIGH or LOW value. If LOW, it worked of its own accord in Automatic

mode whereas if HIGH, it relied on a user input from the aforementioned joystick.

Procedure:

The team met twice a week, on Wednesdays and Fridays for weeks 7 to 11

i. Week 7: Building of robot platform and test motors and IR sensor

Aims: Have robot platform constructed, motors in position and running, test IR sensor

First was to set up the robot with the motors in place and test them with the SN755410 H-Bridge, the circuit we used

for this can be seen below:

Figure 1 - A rough schematic produced in the early stages

Next was to test the IR sensor, the sensor was connected to the Arduino and sample code was used to output the values

to the serial monitor.

ii. Week 8: Tested the servo and sensor combined

Aims: Get the servo and sensor combination working

First was to get the servo rotating 180 degrees side to side. This was controlled from the Arduino next was to set up

the sensor on the rotating servo

iii. Week 9: Assembled the entire robot

Aims: Have full collision detection movement working on the robot

Figure 2 - A basic diagram of the bot at the end of Week 9

The robot was fully assembled and the collision detection code was added to the Arduino.

iv. Week 10: Added our unique feature

The unique feature for the robot was manual control. We sourced a joystick from a PlayStation1 controller. This

output from the joystick was then used to controller the motor speed and direction of the robot.

v. Week 11: Made presentation and report

The compilation of the report began as early as Week 9. We decided that your best approach would be to draft a

report, then use the compiled information to produce a presentation that would accurately reflect the final report.

Figure 3- A graph displaying how our time was divided over the 5 weeks

Unique Aspect:

The robot had a number of unique features:

2 modes: Automatic

Manual

This was controlled by the DPDT Switch.

Automated decision making: Turns left/right depending on read value

20%

40%

10%10%

20%30%

WEEKS 7 -11:

Equipment Testing Code Testing Assembly Presentation Report

Mode Select:

0: Automatic

1: Manual

Figure 4 - DPDT Mode Select

This was implemented by using the “modulo” or “%” function. Here the number was divided by 2 and checks for a

remainder. If reminder exists it’s ODD, otherwise it’s EVEN.

The automated Arduino loop was as follows:

Figure 5 - Automatic FOR Loop Cycle

Manual control using a PlayStation1 joystick: User defined speed control

The Joysticks dual potentiometers and associated integrated circuitry output an analogue signal between 0 and 660

each. These were then mapped to -255 and 255 respectively, allowing the newly mapped values to be fed into the

motors directly to vary speed.

The manual Arduino loop was as follows:

Figure 6 - Manual Loop Cycle

IF RIGHT_SWEEP Complete

• Initiate LEFT_SWEEP

Reads IR Value

IF IR > 550

• Move forward

IF IR < 550

• Turn Left if EVEN

• Turn Right if ODD

IF LEFT_SWEEP Complete

• Initiate RIGHT_SWEEP

Reads IR Value

IF IR > 550

• Move forward

IF IR < 550

• Turn Left/Right

Checks for JoyStick Input

If -20 < X|X< +20|

-20 < Y|Y< +20

HOME: No Movement

IF Y > +20

•Move forward

• The closer to +255, the faster it moves

IF Y < -20

•Move backwards

• The closer to -255, the faster it moves

IF X > +20

• Turn left

• The closer to +255, the faster it moves

IF X < -20

• Turn right

• The closer to -255, the faster it moves

Automatic

Manual

Code:

//”The following are the initial declarations for the Arduino Loop. The integrated Arduino Servo header file is

included. The various pin names and respective numbers are demoted for easier trouble shooting and code

recognition”// #include <Servo.h>

Servo myservo;

int sensorpin_M_A = 4;

int val_M_A = 0;

int pos = 50;

int sensorpin = 1;

int val = 1;

int sensorpin_FB = 3;

int val_FB = 0;

int sensorpin_LR = 5;

int val_LR = 0;

int UP = 3;

int DOWN = 5;

int LEFT = 2;

int RIGHT = 7;

int motor_left[] = {3, 5};

int motor_right[] = {6, 11};

//”void setup is run only once per power up. It is the first snippet of code ran prior to initiating the main loop. Its

purpose is to initiate the declorations stated above and prepare them for use in the loop”// void setup(){

Serial.begin(9600);

pinMode(LEFT, OUTPUT);

pinMode(UP, OUTPUT);

pinMode(DOWN, OUTPUT);

pinMode(RIGHT, OUTPUT);

myservo.attach(10);

int j;

for(j = 0; j < 2; j++){

pinMode(motor_left[j], OUTPUT);

pinMode(motor_right[j], OUTPUT);

}}

//”The beginning of the main loop”// void loop(){

//”The value of an input pin is read. This pin is the MODE pin, the point at which the Arduino decides whether it is in

AUTOMATIC or MANUAL mode. HIGH is considered to be a value greater than 800. Anything less is considered

LOW.”// val_M_A = analogRead(sensorpin_M_A);

Serial.println(val_M_A);

//”The read value is greater than 800, thus MANUAL Mode has been initiated. 2 pins are now read, one for the

Forward&Back or YAxis, the other for Left&Right or XAxis.”// if(val_M_A < 800){

val_FB = analogRead(sensorpin_FB);

val_LR = analogRead(sensorpin_LR);

//”The values are mapped to between -255 and +255”// val_FB = map(val_FB, 10, 660, -255, 255);

val_LR = map(val_LR, 0, 645, -255, 255);

//”The HOME positions are checked for”// if(val_LR < 17 && val_LR > -35)

{

val_LR = 0;

}

if(val_FB < 17 && val_FB > -35)

{

val_FB = 0;

}

//”If both values for F&B and L&R are 0, it is considered home and neither motor moves”// if(val_FB == 0 && val_LR == 0)

{

analogWrite(motor_left[0], 0);


analogWrite(motor_right[0], 0);


}

//”This snippet considers the scenario where F&B is 0 but L&R is not”// if(val_FB == 0 && val_LR != 0)

{

//”If L&R is greater than mapped 17 it turns left with a speed corresponding to the position of L&R. The greater the

value, the faster it turns”// if(val_LR > 17)

{


analogWrite(motor_left[1], val_LR);

analogWrite(motor_right[0], val_LR);

analogWrite(motor_right[1], 0);}

//”If L&R is less than mapped -35 it turns right with a speed corresponding to the position of L&R. Again, the greater

the value, the faster it turns”// if(val_LR < -35)

{

//”It must be noted for this instance that the value of L&R must be inversed in order to have a usable value.”// val_LR = -val_LR;

analogWrite(motor_left[0], val_LR);



analogWrite(motor_right[1], val_LR);

}

}

//”The following snippet considers the scenario where F&B does not equal 0 but L&R does”// if(val_FB != 0 && val_LR == 0)

{

//”If F&B is greater than mapped 17 it moves forward with a speed corresponding to the position of F&B. The greater

the value, the faster it moves”// if(val_FB > 17)

{

analogWrite(motor_left[0], val_FB);


analogWrite(motor_right[0], val_FB);


}

//”If F&B is less than mapped -35 it reverses with a speed corresponding to the position of F&B. Again, the greater the

value, the faster reverses”// if(val_FB < -35)

{

//”It must be noted for this instance that the value of F&B must be inversed in order to have a usable value.”// val_FB = -val_FB;


analogWrite(motor_left[1], val_FB);


analogWrite(motor_right[1], val_FB);

}

}

}

//”We now consider the situation where the read MODE pin value is less than 800, and thusly AUTOMATIC Mode

has been initiated. Here only one pin is read, the pin corresponding to the IR sensor”// if((val_M_A > 800)){

//”The following for loop is used to sweep the IR Servo anticlockwise”// for (pos = 50; pos <= 140; pos += 1)

{

myservo.write(pos);

//”The IR Value is read”// val = analogRead(sensorpin);

Serial.println(val);

delay(10);

//”If the IR Sensor returns a value greater than 550 or 8”s, it continues driving forward”// if (val < 550)

{

drive_forward();

}

//”Otherwise, if less than 550, it divides the value by 2 and checks for a remainder. If remainder doesn’t exist, it turns

left, and turns right if one does exist”// if (val > 550)

{

if(val%2==0)

{

drive_backwards();

delay(750);

turn_left();

delay(750);

}

else

{

drive_backwards();

delay(750);

turn_right();

delay(750);

}

}

}

//”The following for loop is used to sweep the IR Servo clockwise”// for (pos = 140; pos >= 50; pos -= 1)

{

myservo.write(pos);

//”The IR Value is read”// val = analogRead(sensorpin);

Serial.println(val);

delay(10);

//”If the IR Sensor returns a value greater than 550 or 8”s, it continues driving forward”// if (val < 550)

{

drive_forward();

}

//”Otherwise, if less than 550, it divides the value by 2 and checks for a remainder. If remainder doesn’t exist, it turns

left, and turns right if one does exist”// if (val > 550)

{

if(val%2==0)

{

drive_backwards();

delay(750);

turn_left();

delay(750);

}

else

{

drive_backwards();

delay(750);

turn_right();

delay(750);

}

}

}

}

}

//”The following snippets are sub routines. These are called during the above loop to preform smaller tasks, making

the overall code neater and easier to write and be understood.”// void drive_backward()

{





}

void drive_forward()

{





}

void turn_left()

{





}

void turn_right()

{





}

Final Product:

ALBERT: ALBERT stands for the Automated & Livefeed Bot Engineered for infaRed Tracking.

a) Pre-Tidy:

The following are photos from Weeks 7-9. They were taken just after the first official assembly.

Figure 7 - Sideview of ALBERT MK1

Figure 8 - Sideview of ALBERT MK1

Figure 9 - ALBERT MK1’s Rats Nest of Wires

b) Post-Tidy:

The following are photos from Weeks 10 & 11. Once the Joystick was installed and we were happy with its

performance, we decided that the wiring could be much neater and better colour-coded.

Figure 10 - Overhead of ALBERT MK2

Figure 11 - Front View of ALBERT MK2

Figure 12 - CloseUp of ALBERT MK2's Wiring

Problems:

No Common Ground

After uploading the Arduino code to the Arduino Uno chip, we carried out an integration test. We tested to see if the

motor and sensor worked together simultaneously. We saw that the sensor was taking readings but the motor was not

working.

How we solved the problem:

Firstly, we checked to see if the battery was charged with a voltmeter. The battery was working fine, so there

was no problem arising from the power source.

Next, we scanned through the circuit thoroughly multiple times until we found that the circuit did not have a

common ground. Having a common ground in a circuit is very important because it ensures that there is a closed

loop, thus starting the electrical cycle over and over again.

When the problem was identified, we made sure that motor and the sensor was connected to a common ground

so the circuit could have a return cycle.

After connecting up the circuit, we carried out the integration test again and it was a success.

Broken IR sensor

When we tested to see if the IR sensor was working properly, we saw that it produced a sine wave with a

range of 80 – 112. It was supposed to act as a collision detector and tell the robot platform the distance

calculated for a collision with a nearby wall.

We checked the IR sensor code, but everything seemed to be okay.

Next, we used a different sensor to see if the sensor was broken. Our query was answered when we found that

the second IR sensor worked perfectly as it was able to scan for the distance of the wall from robot platform.

Constant Definition in Motor Code

When we integrated the Arduino code to the motor, we saw that robot platform started to spin in circles. This was not

the outcome that we expected. It was clear there was a mistake somewhere in the code.

int j; // Problem came from here. We forgot include ‘int j’//

for(j = 0; j < 2; j++) {

pinMode(motor_left[j], OUTPUT);

pinMode(motor_right[j], OUTPUT);

}

After scanning through the code, we identified the problem straight away. The j variable was not declared as an ‘int’

variable, which lead to a malfunction in the physical implementation of the code causing a failure in movement. After

declarating the j variable, the robot started and performed as expected.

What we learned:

Step-by-step analysis is key to efficiency:

Testing of hardware and its respective code

Implementing nested codes to interface with one another

Things don’t “just happen”:

There is always a reason behind things not working from missing code to incorrect wiring

That despite its “single loop” framework, the Arduino is a powerful tool in engineering:

The key to unlocking its potential is understanding the various aspects of the hardware you're using and how it

interfaces with different components

Recommendations:

Overall, the mini-project was very enjoyable. It was a challenging experience that helped us obtain required skills and

knowledge needed in a working environment. This section will consist of recommendations and opinions from the

student’s perspective, ie what we felt worked well and things that could be improved on.

Mini-Project Structure:

Team Allocation

The team allocation for the mini-project was a great idea. Every team had to have at least one ME student and one ECE

student. Having a variety of engineering backgrounds really improves the team’s overall knowledge. ECE and ME

students would have different strengths, so it is easier for the team to assign different tasks to each member. Also, the

students are exposed to different ways of thinking and creativity, which is very beneficial for adapting to other

backgrounds in team projects in the work place. We recommend that this type of team allocation should be used for all

future years.

Arduino Tutorial

One aspect that could be improved for the mini-project would be an Arduino tutorial before the designated labs for

constructing the robot platform. It would have been very helpful to have a better understanding on what code would be

needed. This would have made team members more confident in the labs. Also, time in the labs would have been used

more efficiently instead of looking online to see what commands to use, which was a very time-consuming process.

Recommendations for participating students:

Keep organized

Organization is a key for the success of any team project. It is good for team morale because everyone is on a same page

and knows exactly what has to be done. A good tip to being organized is to set deadlines for tasks to be completed. We

had four weeks for our team project to be completed, therefore we split the workload into four weeks (4 parts). Another

tip would be to set up a time for meetings, where we can discuss and express any ideas and monitor if the deadlines are

being met.

Work on each part separately

Always work on a separate part. This avoids confusion and makes it easier to find a problem, if one occurs. Do not

construct the whole project and expect that it is going to work on the first attempt. Always perform a unit test, where

you will see if the part of the car is working individually. If it passes the unit test, perform an integration test and see if

different combinations of parts work with each other.

ee319 project report albert

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