stepper motor controller

[messymaverick]

i need big time help on this one please :!:

design a stepper motor controller using a simple digital circuit. it is supposed to activate the phases one by one in cyclic order. the speed of rotation(rev/sec)= no.of steps activated / sec * step angle/360
step angle=1.5 deg
stepper motor current/phase=80mA

design the circuit using johnson ring counter. design the transistor switches using BC557 to drive stepper motor phases.

how do i calculate frequency of the clock signal that will cause the motor to rotate at given speed.

 

[nettron1000]

This sounds like another school homework question, 'cause you can get a single IC that can do all you discribe.

 

[messymaverick]

This sounds like another school homework question, 'cause you can get a single IC that can do all you discribe.

well how 'bout helpin' me out ? i don't need a single ic to do my job, if that was the case i would have interfaced it using 8255A

 

[bogdanfirst]

ok
you can use a 555 to create the frewuency you need. maybe use a pot to adjust the frequency.
how many steps do you have?
a 4017 is a Jonson counter, but it only counts to 10.

 

[stevez]

Regarding the frequency - you should know the number of degrees per step of the motor - from that you would know the number of steps per revolution. Now all you need to do is determine, for the driver/control, how many clock cycles are required for a step. If during the stepping process there is one step per clock cycle then it's easy.