Card-activated Robot
Page last updated 11 Oct 2012, by 
Tanvir Iqbal.
0
replies
Tanvir Iqbal.
0
replies
General Description
The robot uses a card reader to grant access to the user. A user is granted access by scanning a Buzzcard with a valid GTID number. The user may then control the direction, speed, and duration in which the robot will move. A MPR121 Keypad is used to give input to the robot. A Text LCD is used to prompt for input and display feedback.
Usage
1. Swipe a valid BuzzCard
- A valid BuzzCard is one with a GTID inputted into the code in the cardReader method. Swiping an incorrect card will count toward an error count. Once 5 incorrect attempts have been made the user will be required to input a password. (1357)
2. Select the number of moves
- User can choose up to 11 moves. Each move will consist of bearing, motor direction, speed, and duration.
3. Select the direction
- The robot can either move forward(7), left(2), right(10), or backwards(5) by doing a 180-turn.
4. Select motor direction
- The wheels can either move forwards(1) or backwards(2).
5. Select car speed
- Inputs 1-10 will move the robot at a speed where 1 is the slowest and 10 is max speed.
6. Select car duration
- Duration will determine how long the car will be moving at the selected speed.
7. Repeat
- Repeat steps 3 - 6 if number of moves was greater than 1
8. Watch it go
- The robot will start a countdown from 10 seconds and begin to perform the inputted moves. The LCD will display various information such as speed and what direction it is moving.
Components
- mbed
- Small breadboard
- Card reader
- MPR121 I2C Capacitive Touch Sensor
- Text LCD display
- Dual H-bridge breakout
- 4 AA Batteries
- Motor-powered wheels
Interfacing with mbed
- The card reader will read the user's BuzzCard. The card reader is connected to a RS232 serial interface. This will require the TX and RX pins on the mbed. The code use a string compare to find valid GTID numbers from the BuzzCard.
- The MPR121 Touch Sensor will be used to input commands. This will use the I2C pins on the mbed and any other pin. Two 4.7k ohm pullup resistors need to be added to the circuit.
- The Text LCD display will be used to prompt for inputs and display feedback.
- The Dual H-bridge breakout will control the left and right motors. It will need PWM pins on the mbed
Wiring Connections
| mbed | Dual H-bridge Breakout | Robot DC motors | Battery | Touch Keypad | RS232 | LCD |
|---|---|---|---|---|---|---|
| Vin | Vmot | + | ||||
| Gnd | Gnd | - | Gnd | |||
| Vout | Vcc | Vcc | ||||
| p9 | SDA | |||||
| p10 | SCL | |||||
| p11 | IRQ | |||||
| p13 | ||||||
| p14 | ||||||
| p15 | ||||||
| p16 | ||||||
| p17 | ||||||
| p18 | ||||||
| p19 | ||||||
| p20 | ||||||
| p21 | PWMB | |||||
| p22 | BIN2 | |||||
| p23 | BIN1 | |||||
| p24 | AIN1 | |||||
| p25 | AIN2 | |||||
| p26 | PWMA | |||||
| Vout | /STBY | |||||
| A01 | left-red | |||||
| A02 | left-blk | |||||
| B02 | right-blk | |||||
| B01 | right-red |
Video
Problems Encountered/ Future Steps
Turning of the robot (turn left, turn right, turn around) varied depending on the status of the batteries. Other than that, no problem existed. For future work, the robot will be able to track back following the same path it took to come back to the original position. Remote control commands may be implemented.
Program
Import programCard_activated_robot
Sehoon Shon and Tanvir Iqbal's mbed mini project
Last commit 11 Oct 2012 by Se Hoon Shon
Code
#include "mbed.h"
#include "TextLCD.h"
#include <string.h>
#include "motordriver.h"
#include "mpr121.h"
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
DigitalIn a(p5);
DigitalIn b(p6);
DigitalIn c(p7);
DigitalIn d(p8);
InterruptIn interrupt(p11);
// Setup the i2c bus on pins 28 and 27
I2C i2c(p9, p10);
// Setup the Mpr121:
// constructor(i2c object, i2c address of the mpr121)
Mpr121 mpr121(&i2c, Mpr121::ADD_VSS);
//Motor
Motor left(p21, p22, p23, 1); // pwm, fwd, rev, has brake feature
Motor right(p26, p25, p24, 1);
//TextLCD lcd(p15, p16, p17, p18, p19, p20); // rs, e, d4-d7
TextLCD lcd(p15, p16, p17, p18, p19, p20);
Serial pc(USBTX, USBRX); // tx, rx
Serial device(p13, p14); // tx, rx
//forward or in reverse mode
int forward;
//stores directions
int direction[10];
//stores speeds
float speed[10];
//stores durations
int duration[10];
//speed of the car
float car_speed;
//duration of the car
int car_duration;
//stores the command of the touchpad
int _command;
//check if there has been input to the touchpad
bool no_command;
//count variable for card reader
int count=0;
//Number of total moves
int num_moves;
//stores buzzcard information
char output[50];
//number of card swipes on the reader
int num_swipe=0;
int o_a, o_b;
//int count,ch, ignore_count;
int command[12];
int count_1=0;
//password variables
int p_1, p_2,p_3,p_4;
//interrupt routine for touchpad
void fallInterrupt() {
no_command = true;
int s2=0;
int key_code=0;
int i=0;
int value=mpr121.read(0x00);
value +=mpr121.read(0x01)<<8;
// LED demo mod by J. Hamblen
//pc.printf("MPR value: %x \r\n", value);
i=0;
// puts key number out to LEDs for demo
for (i=0; i<12; i++) {
if (((value>>i)&0x01)==1) key_code=i+1;
}
s2 = key_code - 1;
if(s2 > 0){
_command=s2;
no_command = false;
led4=s2 & 0x01;
led3=(s2>>1) & 0x01;
led2=(s2>>2) & 0x01;
led1=(s2>>3) & 0x01;
}
count_1++;
//pc.printf("hello %f\n",s);
}
//function to turn left
void turnLeft(){
lcd.cls();
lcd.printf("Turning Left");
left.speed(0);
right.speed(0.4);
wait(2);
right.speed(0);
wait(1);
}
//function to turn right
void turnRight(){
lcd.cls();
lcd.printf("Turning Right");
left.speed(0.4);
right.speed(0);
wait(2);
left.speed(0);
wait(1);
}
//function to turn around
void turnAround(){
lcd.cls();
lcd.printf("Turning Around");
left.speed(0.4);
right.speed(0);
wait(4);
left.speed(0);
wait(1);
}
//to move with input speed and duration of time
void go(float _speed, int _time){
lcd.cls();
lcd.printf("Speed %f Duration %d sec", _speed, _time);
left.speed(_speed);
right.speed(_speed);
wait(_time);
left.speed(0);
right.speed(0);
wait(1);
}
//starts the card reader and verifies the user
int cardReader(){
num_swipe++;
int count=0;
int ch=0;
int ignore_count=0;
// char output[50];
while(1){
if(device.readable()){
ch=device.getc();
if(ignore_count>5){
output[count]=ch;
count++;
}
ignore_count++;
pc.putc(ch);
}
if (ignore_count>14){
lcd.cls();
if (strcmp(output,"902512409")==0){
lcd.printf("Confirmed\n");
lcd.printf("Welcome Sehoon\n");
for (int i=0; i<1000; i++){
if(device.readable())
device.getc();
}
return 1;
}
else if (strcmp(output,"902536564")==0){
lcd.printf("Confirmed\n");
lcd.printf("Welcome Tanvir\n");
for (int i=0; i<1000; i++){
if(device.readable())
device.getc();
}
return 1;
}
else {
for (int i=0; i<100; i++){
if(device.readable())
ch=device.getc();
wait(.01);
}
if (num_swipe==5){
lcd.printf("Too many tries\nEnter password");
_command=0;
no_command=true;
while(1){
while(no_command){
wait(0.1);
}
p_1=_command;
_command=0;
no_command=true;
while(no_command){
wait(0.1);
}
p_2=_command;
_command=0;
no_command=true;
while(no_command){
wait(0.1);
}
p_3=_command;
_command=0;
no_command=true;
while(no_command){
wait(0.1);
}
p_4=_command;
_command=0;
no_command=true;
if (p_1==1&&p_2==3&&p_3==5&&p_4==7)
{
lcd.cls();
lcd.printf("Correct!!!");
wait(2);
lcd.cls();
lcd.printf("Try swiping AGAIN!!");
break;
}
else{
lcd.cls();
lcd.printf("WRONG WRONG wROGNWRWEWERWER!@#!@");
wait(2);
lcd.cls();
}
}
}
else
lcd.printf("Try again\n");
return 0;
}
}
}
}
//number of moves for the car
int number_of_moves(){
//select duration
//Selecting number of moves
lcd.printf("Select Number of Moves");
num_moves=100;
_command=100;
no_command = true;
while(no_command){
wait(0.1);
}
num_moves = _command;
lcd.cls();
lcd.printf("Number of Moves: %d", num_moves);
wait(2);
return 0;
}
int main() {
interrupt.fall(&fallInterrupt);
interrupt.mode(PullUp);
//Swiping buzz card
lcd.printf("Please Swipe your Buzzcard");
while(!cardReader());
wait(2);
lcd.cls();
number_of_moves();
if (a||b||c||d){
lcd.cls();
lcd.printf("please turn off all switches");
while(1){
if (!(a||b||c||d))
break;
}
}
lcd.cls();
for (int i=0; i<num_moves; i++){
//select direction
lcd.printf("Select Direction2=L 10=R 7=F 5=B");
no_command = true;
_command=0;
while(_command!=2&&_command!=10&&_command!=7&&_command!=5){
wait(0.1);
}
if(_command==2){
direction[i]=1;
lcd.cls();
lcd.printf("Left");
}
else if (_command==10){
direction[i]=2;
lcd.cls();
lcd.printf("Right");
}
else if (_command==7){
direction[i]=3;
lcd.cls();
lcd.printf("Forward");
}
else if (_command==5){
direction[i]=4;
lcd.cls();
lcd.printf("Reverse");
}
wait(2);
lcd.cls();
//select speed
lcd.printf("Move Forward-1 or in Reverse-2");
car_speed=0;
_command=0;
forward=0;;
no_command = true;
while(_command!=1&&_command!=2){
wait(0.1);
}
if (_command==1){
forward=1;
lcd.cls();
lcd.printf("Car moves forward");
}
else if (_command==2){
forward=-1;
lcd.cls();
lcd.printf("Car moves in reverse");
}
wait(2);
lcd.cls();
_command=0;
lcd.printf("Select Car Speed 1-10");
while(_command!=1&&_command!=2&&_command!=3&&_command!=4&&_command!=5&&_command!=6&&_command!=7&&_command!=8&&_command!=9&&_command!=10){
wait(0.1);
}
car_speed=forward*_command*0.1;
speed[i]=car_speed;
lcd.cls();
lcd.printf("car speed: %d\n", _command);
wait(2);
lcd.cls();
//select duration
lcd.printf("Select Car duration 1-10 seconds");
car_duration=0;
_command=0;
while(_command!=1&&_command!=2&&_command!=3&&_command!=4&&_command!=5&&_command!=6&&_command!=7&&_command!=8&&_command!=9&&_command!=10){
wait(0.1);
}
car_duration=_command;
duration[i]=car_duration;
lcd.cls();
lcd.printf("car duration: %d seconds\n", _command);
wait(2);
lcd.cls();
}
for (int i=10; i>0; i--){
lcd.printf("Car will start in %d seconds",i);
wait(1);
lcd.cls();
}
lcd.printf("GO GO GO GO GO GO GO GO GO !!!");
wait(1);
for (int i=0; i<num_moves; i++){
switch (direction[i]){
case 1:
turnLeft();
break;
case 2:
turnRight();
break;
case 3:
break;
case 4:
turnAround();
break;
}
go(speed[i], duration[i]);
}
lcd.cls();
lcd.printf("Finished");
}
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