Posts Tagged ‘stepper motor’
First custom PCB
This is my first working printed circuit board. I used the toner transfer method to draw the traces on the copper board. The purpose of this circuit board is to drive a stepper motor. This is a proof of concept for the final board version that will complete my equatorial mount project. The equatorial mount will be my first project in my new “Projects” section. I will begin with the conception and the making of this board.
Arduino Stepper Motor Controller PCB
I have designed the PCB using Fritzing, an open source circuit designer. You can find the project and the PDF of the circuit on my github. More details to come in the Projects section … hopefully in a few days.
PCP Details
I had a bit of troubles soldering the power connector because I drilled the holes too large. I’ll have to renew my stocks of small drill bits … I broke two 1/32″ bits while doing this board!
No Comments »
Arduino Timer Interrupt
I am actually working on a small project using an Arduino micro-controller ATMEGA 328. Timing issues are very critical so I had to find a way to use timer interrupts.
Arduino, Allegro 5804 and stepper motor
I found the following code and adapted it to the ATMEGA 328.
http://gonium.net/md/2006/12/27/i-will-think-before-i-code/
Following is my implementation for the ATMEGA 328 … The code is driving a stepper motor through the Allegro 5804 stepper motor driver.
#include <avr/interrupt.h>
#include <avr/io.h>
#define INIT_TIMER_COUNT 6
#define RESET_TIMER2 TCNT2 = INIT_TIMER_COUNT
#define CW HIGH
#define CCW LOW
// One and two phases
// 60000ms / 48steps = 1250ms/step
#define TRACK 1250
// Half steps
// 60000ms / 96steps = 625
//#define TRACK 625
int led13 = HIGH;
long counter = 0;
int stepStack = 0;
// Aruino runs at 16 Mhz, so we have 1000 Overflows per second...
// 1/ ((16000000 / 64) / 256) = 1 / 1000
ISR(TIMER2_OVF_vect) {
RESET_TIMER2;
counter++;
if(!(counter%TRACK))
{
// enqueue step message
stepStack++;
}
};
void setup()
{
pinMode(2, OUTPUT); // Step
pinMode(3, OUTPUT); // Direction
pinMode(13, OUTPUT); // LED
pinMode(4, INPUT); // Power on/off
pinMode(5, INPUT); // Rewind
//Timer2 Settings: Timer Prescaler /64,
TCCR2A |= (1<<CS22);
TCCR2A &= ~((1<<CS21) | (1<<CS20));
// Use normal mode
TCCR2A &= ~((1<<WGM21) | (1<<WGM20));
// Use internal clock - external clock not used in Arduino
ASSR |= (0<<AS2);
//Timer2 Overflow Interrupt Enable
TIMSK2 |= (1<<TOIE2) | (0<<OCIE2A);
RESET_TIMER2;
sei();
}
void loop()
{
// READ INPUTS
int fast = digitalRead(4);
int rewind = digitalRead(5);
if(rewind == HIGH || fast == HIGH)
{
// Toggle the LED
led13 ^= 1;
digitalWrite(13, led13);
// Clear the step messages buffer
stepStack = 0;
// Set rewind direction
if(rewind == HIGH)
digitalWrite(3, CCW);
else
digitalWrite(3, CW);
digitalWrite(2, HIGH);
delay(10);
digitalWrite(2, LOW);
delay(10);
}
else if(stepStack)
{
// Toggle the LED
led13 ^= 1;
digitalWrite(13, led13);
// Set tracking direction
digitalWrite(3, CW);
digitalWrite(2, HIGH);
delay(1);
digitalWrite(2, LOW);
delay(1);
stepStack--;
}
}
5 Comments »
