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Stepper Motor PBASICs ...

Link 2 StampWorks Manual see page 150 ... circuit setup page 146 ... program example page 151

Stepper Motor Driver Board and Stepper Motor = $4.09

From the BS2 pins on the left to the little RC timing circuit on the Right
0.1µF capacitor = 104 ... and ... 220Ω = Red Red Black

From the BS2 pins on the left to the ULN2003 stepper motor driver board on the right

- the program -

' StampWorksManual-ULN2003-1.bs2
' SPECIAL NOTES
' Pin 8 goes to ground.·
' Pin 9 - com - goes to the positive side of whatever voltage you are using
' for the outputs, 5V, 9V, 12V, anything up to 40V.
' Hook up a ULN2003 with 5V on pin 8, ground on pin 9.
' Common wire of stepper motor on 9 and
' coils 1 through 4 on pins 10 to 13.
'************************************************************************************
********************************************** ' The Motor and Driver Board Used instead of the LM239
' http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=26925&aff=757677
'
' Driver Board Specs:
' ULN2003 Darlington using HIGH-power stepper motor driver chip A, B, C, D four-phase LED indicates the status of the stepper motor.
' Dimensions: 35×31x12mm
' Weight: 7g
'
' Motor Specs:
' Diameter: 28mm
' Voltage: 5V
' Step angle: 5.625 x 1/64
' Reduction ratio: 1/64
' Weight: 33.5g
' *************************************************************************************
*********************************************

' {$STAMP BS2}
' {$PBASIC 2.5}
' -----[ Program Description ]---------------------------------------------
'
' This program demonstrates simple stepper motor control. A potentiometer
' allows for speed and direction control. Using the L293D driver, this
' program will work with unipolar and bipolar stepper motors.
' -----[ I/O Definitions ]-------------------------------------------------
PotCW PIN 0 ' clockwise pot input
PotCCW PIN 1 ' counter-cw pot input
Coils VAR OUTB ' output to stepper coils
' -----[ Constants ]-------------------------------------------------------
Scale CON $100 ' to scale RCTIME
'Mitsumi CON 48 ' steps/rev by type 48
HobbyKing CON 80 ' steps/rev by type 80
Howard CON 100
RevSteps CON Mitsumi ' steps per revolution
NumSteps CON 4 ' use 4-step sequence 4
LastStep CON NumSteps - 1 ' last step in sequence
#DEFINE Testing = 0 ' 1 for POT testing
' -----[ Variables ]-------------------------------------------------------
idx VAR Byte ' loop counter
stpIdx VAR Nib ' step pointer
stpDelay VAR Byte ' delay for speed control
rcRt VAR Word ' rc reading - right
rcLf VAR Word ' rc reading - left
diff VAR Word ' difference in readings
' -----[ EEPROM Data ]-----------------------------------------------------
' __
' ABAB
' -----
Step1 DATA %1100
Step2 DATA %0110
Step3 DATA %0011
Step4 DATA %1001
' -----[ Initialization ]--------------------------------------------------
Setup:
DIRB = %1111 ' make P4..P7 outputs
stpDelay = 5 ' set step delay
' -----[ Program Code ]----------------------------------------------------
Demo:
FOR idx = 1 TO RevSteps ' 1 rev forward
GOSUB Step_Fwd
NEXT
PAUSE 200
FOR idx = 1 TO RevSteps ' 1 rev back
GOSUB Step_Rev
NEXT
PAUSE 200
Main:
HIGH PotCW ' read clockwise position
PAUSE 1
RCTIME PotCW, 1, rcRt
HIGH PotCCW ' read ccw position
PAUSE 1
RCTIME PotCCW, 1, rcLf
rcRt = (rcRt */ Scale) MAX 600 ' set speed limits
rcLf = (rcLf */ Scale) MAX 600
diff = ABS (rcRt - rcLf) ' get difference
stpDelay = 100 - (diff / 6) MIN 2 ' calculate step delay
IF (diff < 25) THEN ' allow for dead band
GOTO Main
ELSE ' do a step
IF (rcLf < rcRt) THEN
GOSUB Step_Fwd
ELSE
GOSUB Step_Rev
ENDIF
ENDIF
GOTO Main ' repeat
' -----[ Subroutines ]-----------------------------------------------------
' Turn stepper clockwise one full step
Step_Fwd:
stpIdx = stpIdx + 1 // NumSteps ' point to next step
GOTO Do_Step
' Turn stepper counter-clockwise one full step
Step_Rev:
stpIdx = stpIdx + LastStep // NumSteps ' point to previous step
GOTO Do_Step
' Read new step data and output to pins
Do_Step:
READ (Step1 + stpIdx), Coils ' output new coil data
PAUSE stpDelay ' pause between steps
RETURN

************************************************************************************

Wiring Diagram ...

Now a the same Stepper Motor and Parallax HomeWork Board but with the SparkFun Easy Stepper Driver

Sample Stepper Motor D.A.I.R.-S42 BS2 PBASIC to get you started;

Full Speed Loop for Stepper Motor;
cwfullspeed:
DEBUG CR, "Full Speed Clockwise", CR
FOR I = 1 TO 1600 ' 1-full revolution of test motor pulled from an ATM machine is 1600 STEPS
LOW 0 ' BS2 PIN 0 to Direction Pin on motor controller
LOW 1 ' Pre STEP set LOW to ramp up for triggering a STEP from BS2 PIN 1 to motor controller STEP pin
HIGH 1 ' STEP from BS2 PIN 1 to motor controller STEP pin causes motor to take a STEP
NEXT
RETURN

ccwfullspeed:
DEBUG CR, "Full Speed Counter Clockwise", CR
FOR I = 1 TO 1600 ' 1-full revolution of test motor pulled from an ATM machine is 1600 STEPS
LOW 0 ' BS2 PIN 0 to Direction Pin on motor controller
LOW 1 ' Pre STEP set LOW to ramp up for triggering a STEP from BS2 PIN 1 to motor controller STEP pin
HIGH 1 ' STEP from BS2 PIN 1 to motor controller STEP pin causes motor to take a STEP
NEXT
RETURN

Adding MicroSTEPS is easy with the motor controller I'm using;
cw:
DEBUG CR, "Clockwise", CR
FOR i = 1 TO 400 ' Step Count
LOW 0 ' Direction
LOW 1 ' Pre STEP
HIGH 1 ' STEP
HIGH 2 ' MS1 set the MS1 PIN
HIGH 4 ' MS2 set the MS2 PIN
' PULSOUT 1, 1000 ' STEP Speed
' PAUSE 5
NEXT
RETURN

MS1 - MS2 Use Chart
-----------------------------
LOW - LOW = FULL STEP
HIGH - LOW = HALF STEP
LOW - HIGH = QUATER STEP
HIGH - HIGH = EIGHTH STEP
Just set MS1 HIGH for 1/2 STEPs and setting both MS1 and MS2 HIGH gives 1/8th STEPs...
Adding a PAUSE before the NEXT in the example FOR/NEXT loops you can slow down the speed of the motor.