Reducing number of pins needed to control stepper?

hi,

is there anyway reduce number of pins arduino control stepper motor?

i'm using 28byj-48 , uln2003 drivers , takes 4 arduino pins control.  in final project have 4x motors (taking 16 pins up) , 6 switches various things such limit switches (taking 6x pins).  that's 22x pins more uno has available.

is option use driver board (like easydriver) supports i2c or has else got suggestions on how can reduce number of pins needed control steppers?

i thinking shift registers couldn't head around how able incorporate them.

appreciate suggestions!
thanks

use several separate stepper drivers, on own boards.   for regular stepper motors, they're dirt cheap, and/or built arduinos , transistors.

i'm making own arduino based driver right hard drive motors.  if go diy route, can use api example stepper functions , code.

like you've seen, steppers need @ least 4 wires, 2 each phase.

stepper drivers need 2 pins, step , dir.   

step pulse saying move 1 step. 
dir cw/ccw high or low.   
easy.   it needs attached common ground too, doesn't take pin. 
also, you'd give right power motor, switched transistors or motor driver ic.

look @ how cnc stuff grbl works.  2 pins per motor.

the attached o'scope picture ideal waveform on both pins. 
the green square wave tells step each time state goes high. 
the red line high or low indicate cw or ccw.

the other picture testing board on white breadboard, , green 1 organized version.  doesn't have wires attached yet.

you may (will) want protection diodes and/or capacitors keep transistors safe.


i hope helps.

Arduino Forum > Using Arduino > Motors, Mechanics, and Power (Moderator: fabioc84) > Reducing number of pins needed to control stepper?

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