For the motors lab, because I didn't have access to an h-bridge, I worked with Stepper motors instead of DC motors, using unipolar steppers that could be run with transitors (or transistor arrays) instead of h-bridges.
Working with the steppers went very smoothly, once the wiring of the motors were figured out. Unipolar stepper have six wires running out of them, two of which go to power and four others. There was a minor crisis with this because the notes on stepper motors on the pcomp site actually had typos in them which mixed up the wires and caused untold confusion. We wound up seeking Caryn's assistance and testing the resistance between each wire to figure out which was what.
After that was solved, the actual wiring was pretty easy. Also, we used 12 volt steppers, so we ran 12 volts from our power into another bread board, hooking up the stepper power to that, instead of running it from the micro-controller or the 5v regulator.
Here is an image of the final set up:
I them programmed the pic to step in one direction if a switch was flipped one way, and in another direction if it was flipped another from the code notes on the pcomp page.
I them changed the code to move 10 steps when a switch was flipped. Accidently declared my index variable for my for loop as a bit and not a byte, so it didn't have enough storage to count to 10 at first, but fixed that and it worked just fine.
start:
High PORTB.0
' set variables:
x VAR BYTE
steps VAR WORD
previous var bit
stepArray VAR BYTE(4)
i var byte
clear
TRISD = %11110000
PORTD = 255 input
portb.4
Pause 1000
stepArray[0] = %00001010
stepArray[1] = %00000110
stepArray[2] =%00000101
stepArray[3] = %00001001
previous = 0
main:
if portb.4 = 1 then
if previous = 0 then
for i = 0 to 9
steps = steps - 1
portD = stepArray[steps //4]
pause 200
next
endif
previous = 1
else
previous = 0
endif
goto main