this is my third project, it turned out very useful,so i'd like to share it with people.
i have a parallel port with only 6 functioning data outputs.
so i think twice before i do something.
for example,controlling two stepper motors at once.or sixteen at once etc..
there are probably tiny chips out there that do what my device does,but i like designing stuff.
this device accepts,only two inputs, a clock line (pulse), and a direction line for our motor.
and magically,it outputs the right sequence of bits to drive the motor with its four outputs.
i use it with my parallel port,but it can also be driven with a 555 timer,or any other clock source.
Step 1: step1
this device is tested on my system,and works with the parts that i have, and i don't have extensive electronics knowledge ,so be careful before you hook this up to your computer,and do your math twice. i can't be held responsible for any damage to your equipment or if you hurt yourself.
i have a very old computer that i don't care about,and many transistors to burn.so i simply build the circuit,and try it out.
luckily this circuit turned out great,and powerful.
a little theory:
i have two kinds of steppers,4 cables and 6 cables.however they both require 4 control cables.
the stepper is a great toy to play with,but it won't start directly right after you apply some voltage.
you have to send the data in a sequence.so that the coils start making the armature turn.
here is the sequence i found out thru trial and error,plus some google search.
o1 o2 o3 o4
0 0 0 1
0 0 1 1
0 0 1 0
0 1 1 0
0 1 0 0
1 1 0 0
1 0 0 0
1 0 0 1
while it is easy to create this sequence thru the parallel port using four outputs,we can create it using only two cables. one for the pulse, and the other for the direction.
go to step 2 to see how