Manual control of stepper motor

[vulcom1]

I have searched for a diy method of how to manually control a 6volt 2 amp stepper motor. I have a medical problem with my right sholder and want to be able to move the table on my mill/drill using variable resistor for speed and a toggle switch for direction. I have installed 2 steppers that belt drive the table and eventually will upgrade the components for a 3 axis cnc. I have built a cnc foam cutter using the Hobbycnc board but would like to mount the manual control on the machine itself so I don't have to keep going to the computer to move the table. Turning the handles with the steppers connected even with out power is a too much of a problem.
If someone has an idea how to go about controling the stepper or a schematic it would be appreciatted. As a last resort I may have to figure out a way to disengage the drives so I can use it normally.
Thanks, John

[vtxstar]

What you describe - a variable resistor and toggle switch - would really be the control section of a stepper drive. Nearly all the stepper drives I have studied have the two basic inputs: Step (or /Step) and Direction (CCW/CW).

The "Flip-Flop - NOR gate" type circuit that drives four transistors (one for each winding of the motor) does this. In the case of a variable resistor for speed control, it would vary the input to a 555 or op amp oscillator. The output would be the Step signal.

The toggle switch will pull the Direction line to a logic Hi or Low.

I am currently working on such a thing to make the adjustments for my 3 axis circuit board machine (a Kleinbauer Brute). I have seen several single and dual axis offerings on ebay but with no techincal information regarding inputs.

Of course you would have to swap control of your motor from the computer to the manual drive when you want manual control. This would require a few more wires and another switch.

Perhaps someone on the board has a ready-to-go set up they know of to help this fellow?

[pminmo]

http://pminmo.com/phpBB2/viewtopic.p...d2aa84b9d#1946

Middle of the page is a 555 timer circuit. Pinout for the db25 of the HCNC board would be different.

[vulcom1]

Phil,
Thanks for the info and will see if I can build something to go with the circuit. I don't have any boards but will build 2 controllers for manual operation. I don't want to hook something up to the pc in case I let the smoke out.
I will search some more to find a circuit that the driver chips are easier to come by.
Thanks, John

[Corruptor]

I'm not an electronic guru, so I looked for a board that allows manual inputs. I ended up buying a "Dragon Driver" board from an Ebay store. It's got several options for input connections. I hooked up a power supply and several switches to control direction, full/half step, hi/low speed.

My application is a powered router lift in a regular router table. I wanted manual control first with the ability to go for computer control later. I'm not certain that the driver board I bought will allow that, but I think it will. Again, I'm no an electronics guy and I'm new to the DIY CNC world, so double check everything if you go this route.

Anyhow, here's a US Ebay auction for the driver board (same ebay store I bought it from).
Dragon Driver

The router table is in storage right now, but I think I have a diagram somewhere that shows my wiring schematic. If you want more info, PM me and I'll see what I can find.

[vger]

If you have a spare high count (>1000 ppr) encoder laying around and build up an decoder for it.... Make a small flywheel knob for it.

If you have an old camcorder you can hack apart, the zoom curcuit and cotrol board/motor could be used to drive the opto wheel from a mouse. Still make the decoder for the quadrature output of the mouse wheel.

A stepper motor could be used as a pulse gen as well. You may want to volt limit the output going to the drive with a zener though.

Steve

[Buchsenmacher]

I am looking for dragon driver data sheet. Secifically which input can be used to jog the driver. I believe one of the terminals is a 5v outut that can be connected to another terminal to jog the controller.
Thanks.

[toughtool]

Here is a circuit that will drive a uni-polor stepper (4 of them). I have a circuit for a bi-polar (H drive) version but have not built and tested it. This one has the X and X-2 motor drivers connected together for a two motor X axis type CNC. The MOSFET transistors are rated to 49 amps at 60 volts. I use 24 volts and a series resistor (5 ohms/25 watt) to limit my motor winding currents to 1.4 amps @ 4.5 volts.
Notice in the lower left corner of the schematic, you will see an AND gate oscillator with a variable resistor. This resistor is picked to give a wide range of oscillation pulses, for slow to fast stepping. By using the pushbuttons for step and switches for direction, this should work fine (for manual operation).Then when you get the rest of your CNC stuff connected to the mill, you can connect the computer to the drivers' DB25 parallel port, load EMC2 on your Linux machine and you will have a CNC, for free. Joe

[toughtool]

vulcom1
Here is a simpler version of the driver. uses 3 IC's at about $1.50, and 4 MOSFETs at about $1.50 each.Joe

[vulcom1]

Thanks for the reply's. The thread started in 2008 so I am okay now for circuits.
John

[Corruptor]

Originally Posted by Buchsenmacher I am looking for dragon driver data sheet. Secifically which input can be used to jog the driver. I believe one of the terminals is a 5v outut that can be connected to another terminal to jog the controller. Thanks.

Here's one I found a long, long time ago. It's not the best copy, but it should have the info you're looking for.