Quote: hmmmm I dont recommend bothering with steppers right now, they can be challenging for a beginner. Just stick with the servos
...the problem Admin is that servos here (india) are very expensive Rs650 was the cheapest that i could find.
i want to keep my budget under Rs.1000 (1$=Rs39.50) for the entire robot.
so i m left either with stepper or the dc with h bridge. but i dont trust the dc motors as they can be very fast and annoying and thus the robot can easily go off line, and even if you use low freq. PWM then too usefull battery power is wasted.
question that i have already searched the forum for and am not answered is:
1.in case of a 5 wire unipoler stepper motor why do we need to use a controller. we can easily control it this way:
plug the common wire to +12V and the 4 control wires to any four ports of mcu. (say PC0...PC3 of atmega16) and then code accordingly, say to roll forward one complete rotation...
DDRC=0x00; //config portc as output port
int array[]={0b01111111,0b10111111,0b11011111,0b11101111}; //current flows while port bit=0
int i,j;
for(i=0;i<200;i++) //200x to complete 200x1.8 deg= 360 deg complete rot.
for(j=0;j<4;j++) //4x to complete 1.8 deg step angle
PORTC|=array[j];
...so is it right or have i got something wrong?
2. there seems to be some problem with your photovore + sorutils source code, my avrstudio 4 dosn't seem to have a header file called "a2d.h". even when i copy pasted your a2d.h and a2d.c in the include folder of winavr the problem seems to persist. so i cannot seem to interface and use the ADC ports (PORTA) of mcu to take my sensor readings.
PS>I have almost finished doing the entire ckt diag. of the robot.(in pen and paper off course,its always convinient the old fashioned way) and would probably finish the program very shortly. I dont have any of the hardware yet but hopefully would get all my parts by mid nov 07. before that happens i intend to put in paper and then in this post all the nitty gritty of the final product (ckt diag, algo, prog, actual physical diag) and have it approved by the ADMIN and possibly the other members (if they are kind enough) for any possible mistakes....am on a very tight budget...can't afford a mistake and retry.
