Society of Robots - Robot Forum
Software => Software => Topic started by: HSG on June 17, 2012, 11:07:09 AM
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Hi there, Experts!
I have decided to make the $50 robot, and started by laying out the electronics on a breadboard (not connecting servos and photoresistors), and downloading , building and uploading the photovore /$50 robot code supplied by admin.
I use atmega8 uC, AVR ISP mk2 programmer, and AVR studio 5.1
There are no error messages when I build the code, or when I program the atMega8 uC (memories -> Program)
However, the LED does not come on as PD4 port does not go low. :(
If anyone has any ideas about how I can troubleshoot this, it would be highly, highly appreciated!
Regards,
HSG
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Have you written software to tell it to go low - as nothing else will.
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Hi Webbot!
Thanks for the reply.
I am using the photovore code, and I have tried to uncomment both the LED_on() and LED_off() calls.
From SoR_Utils.h, it seems like LED_on(), should do the trick by making PD4 go low.
Is there something fundamentally I haven't understood? :S
Regards,
HSG
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I think that when I made the $50 robot, I had to chance the code a bit for the LED to work. Check this post: http://www.societyofrobots.com/robotforum/index.php?topic=13795.msg102029#msg102029 (http://www.societyofrobots.com/robotforum/index.php?topic=13795.msg102029#msg102029)
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Hi Advanvasco!
Thanks for your reply.
Changing from LED_off() to LED_on() (by commenting/uncommenting) was actually one of the first things I tried.
Or is it more to the changes you did than this?
Regards,
HSG
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Can you post your source code? Both you .c file (Photovore_v1.c I think) and SoR_Utils.h.
I understand that you have checked the voltage on the pin with a voltmeter of some sort.
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The other common cause is that folk have soldered the LED the wrong way around so it will never light.
At your own risk:
Take the mcu out of the socket to prevent damage and remove any power supply from the board
Take a battery 4v to 9v say .... and connect the leads from the battery:
(+ve)-----resistor-----led----(-ve)
since the $50 robot has nothing else connected to these pins then its safe to try the battery leads the other way ie
(-ve)-----resistor-----led----(+ve)
If neither combination works then you have either soldered the LED in the wrong way around or the LED is dead.
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Hi Adanvasco!
Yes, I measured the voltage between the PD4 and GND using a multimeter, and its 4.9V.
The code is found below - its essentially unmodified from the original, except for the LED_off being changed to LED_on()
Regards,
HSG
Photovore_v1.c
//SoR Include
#include "SoR_Utils.h" //includes all the technical stuff
int main(void)
{
//declare variables here
//int i=250;//a 'whatever' variable
int sensor_left=0;//left photoresistor
int sensor_right=0;//right photoresistor
int threshold=8;//the larger this number, the more likely your robot will drive straight
configure_ports(); // configure which ports are analog, digital, etc.
a2dInit(); // initialize analog to digital converter (ADC)
a2dSetPrescaler(ADC_PRESCALE_DIV32); // configure ADC scaling
a2dSetReference(ADC_REFERENCE_AVCC); // configure ADC reference voltage
/*********ADD YOUR CODE BELOW THIS LINE **********/
configure_ports();
LED_on();//turn LED on
while(1)
{
//store sensor data
sensor_left=a2dConvert8bit(5);
sensor_right=a2dConvert8bit(4);
//detects more light on left side of robot
if(sensor_left > sensor_right && (sensor_left - sensor_right) > threshold)
{//go left
servo_left(44);
servo_right(44);
}
//detects more light on right side of robot
else if(sensor_right > sensor_left && (sensor_right - sensor_left) > threshold)
{//go right
servo_left(25);
servo_right(25);
}
//light is about equal on both sides
else
{//go straight
servo_left(25);
servo_right(44);
}
/* Servo Test Code
i=250;
while(i>0)
{
servo_left(40);
i--;
}
i=250;
while(i>0)
{
servo_left(24);
i--;
}
*/
//rprintf("Initialization Complete\r\n");
//output message to serial (use hyperterminal)
//print("Hello, World! Read My Analog: %u\r\n", sensor_0);
delay_cycles(500);//a small delay to prevent crazy oscillations
}
/*********ADD YOUR CODE ABOVE THIS LINE **********/
return 0;
}
Sor_utils :
//AVR includes
#include <avr/io.h> // include I/O definitions (port names, pin names, etc)
#include <avr/interrupt.h> // include interrupt support
//AVRlib includes
#include "global.h" // include global settings
//#include "buffer.h" // include buffer function library
//#include "uart.h" // include uart function library
//#include "rprintf.h" // include printf function library
//#include "timer.h" // include timer function library (timing, PWM, etc)
#include "a2d.h" // include A/D converter function library
//define port functions; example: PORT_ON( PORTD, 6);
#define PORT_ON( port_letter, number ) port_letter |= (1<<number)
#define PORT_OFF( port_letter, number ) port_letter &= ~(1<<number)
#define PORT_ALL_ON( port_letter, number ) port_letter |= (number)
#define PORT_ALL_OFF( port_letter, number ) port_letter &= ~(number)
#define FLIP_PORT( port_letter, number ) port_letter ^= (1<<number)
#define PORT_IS_ON( port_letter, number ) ( port_letter & (1<<number) )
#define PORT_IS_OFF( port_letter, number ) !( port_letter & (1<<number) )
//************CONFIGURE PORTS************
//configure ports for input or output - specific to ATmega8
void configure_ports(void)
{
DDRC = 0x00; //configure all C ports for input
PORTC = 0x00; //make sure pull-up resistors are turned off
DDRD = 0xFF; //configure all D ports for output
DDRB = 0xC7; //configure B ports 0, 1, 2, 6, 7 for output (google search '0b11000111 to hex')
}
//***************************************
//************DELAY FUNCTIONS************
//wait for X amount of cycles (23 cycles is about .992 milliseconds)
//to calculate: 23/.992*(time in milliseconds) = number of cycles
void delay_cycles(unsigned long int cycles)
{
while(cycles > 0)
cycles--;
}
//***************************************
//*********SIMPLIFIED FUNCTIONS**********
//functions to make coding easier for a beginner
//but could cause port mixup confusion for intermediate users
void LED_on(void)
{
PORT_OFF(PORTD, 4);//turn LED on
}
void LED_off(void)
{
PORT_ON(PORTD, 4);//turn LED off
}
void servo_left(signed long int speed)
{
PORT_ON(PORTD, 0);
delay_cycles(speed);
PORT_OFF(PORTD, 0);//keep off
delay_cycles(200);
}
void servo_right(signed long int speed)
{
PORT_ON(PORTD, 1);
delay_cycles(speed);
PORT_OFF(PORTD, 1);//keep off
delay_cycles(200);
}
//***************************************
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Hi Webbot!
Thanks for your suggestion
I am prototyping using a breadboard, and I have independently verified that the LED works and that the orientation is right..
Regards,
HSG