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Building a Manual Stepper Controller |
Here is the
original circuit presented by Mariss Freimanis on the Yahoo CAD CAM DRO
group:

I modified
the original circuit slightly to accept Step In and Direction In inputs
so that you can use the controller in conjunction with other sources of
stepper pulses. For example, you could run the Step/Dir connections from
a CNC breakout card to these inputs and be able to run either CNC or Manual
control.
Here is the
revised schematic (developed with ExpressPCB.com's free software):

Manual Stepper Motor Controller Schematic
Warning!
This circuit is untested and unsupported. Use at your
own risk. I haven't even built it, and know for a fact there is at least
one error (tying the AND gate outputs together) that would prevent it
working properly.
Connections
+5V Supply
Ground
Forward: Ground
to start running forward.
Reverse: Ground
to start running in reverse.
Potentiometer
Low: 1M ohm speed control potentiometer.
Potentiometer
Wipe + Hi: 1M ohm speed control potentiometer. Tie the wiper to high and
connect.
Select Controller:
Ground for controller to drive step and direction outputs
Pass Through:
Ground to pass Step In to Step Out and Direction In to Direction Out
Step Out: To Gecko
Drive.
Direction Out:
To Gecko Drive.
Parts List (BOM)

Circuit Board
Layout
Here is what
the board would look like according to ExpressPCB:

Manual Stepper Controller PC Board Layout
According to
their pricing wizard, you could purchase quantities of these boards from
them for the following prices:
| 2 |
$98.83 = $49.42 per board |
| 4 |
$116.84 = $29.21 per board |
| 10 |
$170.86 = $17.09 per board |
|
30
|
$352.92 = $11.76 per board |
As you can
see, there is a significant fixed setup cost, so ordering lots of boards
gets the per-board price to go way down. I've also been told by two different
individuals that it would be easy to lay this board out for single layer,
which would save a lot of costs. I may take a look at that. I can already
see some ways to improve on this layout, and I've also been advised of
some errors which I'm working on fixing.
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