Stepper Motor control

[Wayne J]

Hey guys, I got a little personal project going and thinking a stepper motor will work out well. Problem is, I can't find the circuit I am looking for to control it.
What I want to do is.... the motor to start at 0 degrees, then I want to flip a switch and it rotate to 90 degrees and holds. Flip the switch back, and it returns to 0 degrees.

If I can find one that works, I would rather use a linear motor and control it the same way.

Can you guys help?

[dnesci]

Wayne,

How much power does the motor need? There are several model railroading stall motor out there that can be set to stall at 90 degrees and then revered with a double pole double throw switch to go back and stall at 0 degrees. Most need resiters for model RR use as they are powerful enough to bend the track at full voltage. They can be run at 6-12 volts DC.


Other wise here is a stepper motor control circuit http://home.cogeco.ca/~rpaisley4/Bipolar.html

Don

[Wayne J]

Wayne,

How much power does the motor need? There are several model railroading stall motor out there that can be set to stall at 90 degrees and then revered with a double pole double throw switch to go back and stall at 0 degrees. Most need resiters for model RR use as they are powerful enough to bend the track at full voltage. They can be run at 6-12 volts DC.



Don

Sounds interesting and may work, have any links?

[Matt_Edwards]

Wayne,
your ap sound more suited to a servo motor.
Have a look at this example (http://www.sentex.net/~mec1995/gadgets/servo4.htm)
In your case you would replace P1 with two resistor as a switch.

[Wayne J]

Wayne,
your ap sound more suited to a servo motor.
Have a look at this example (http://www.sentex.net/~mec1995/gadgets/servo4.htm)
In your case you would replace P1 with two resistor as a switch.

That was my first idea, but it would need the use of two pots wired to the switch to achieve the results I need.

[eswets]

If the servo works for your design, Matt's link will work fine. You just have to find the resistor values for the degree setting for 0 then add a switch and second resistor in parallel to the circuit. So if R2 needs to be 100ohms (just throwing out values) for 0deg, and 90deg needs to be 50ohms, you need 2 100ohms resistors in parallel but one needs to be switched.

[smartalec]

might sound silly, but what about your windscreen wiper motor from a car?


Hey guys, I got a little personal project going and thinking a stepper motor will work out well. Problem is, I can't find the circuit I am looking for to control it.
What I want to do is.... the motor to start at 0 degrees, then I want to flip a switch and it rotate to 90 degrees and holds. Flip the switch back, and it returns to 0 degrees.

If I can find one that works, I would rather use a linear motor and control it the same way.

Can you guys help?

[mmulvenna]

Although I have not built it yet, I purchased Franks servo controller. His website indicates it will also drive a stepper motor with a slight modification.

[Entropy]

Wayne, how are your microcontroller skills?

This would be something pretty easy to do with a PIC or AVR, even using one of the "abstraction layer" development environments (Basic Stamp for PIC, Arduino dev environment for AVR.)

[j1sys]

Entropy - good idea.

let's take it one step further.

What about taking a low voltage version of something like an SS8, replacing Renard code with 'Renard-Stepper' code (needs to be written) that would consume 8 slots like a usual Renard and then use one or two of the slots to drive one or two stepper motors hooked up to the outputs. Need to work out a lot of details, but couldn't a 'Renard-Stepper' be used for many projects.

-Ed

[ErnieHorning]

Wayne, it would be easier to give you suggestions if you gave even a small clue as to what you’re trying to do. This could be as simple as a DC motor and a double throw switch.

[Wayne J]

Wayne, it would be easier to give you suggestions if you gave even a small clue as to what you’re trying to do. This could be as simple as a DC motor and a double throw switch.


Controlling a flow valve. So, I need to be able to adjust the open and close positions is why the stepper motor.
I was thinking a PIC based unit (very small) would be good.

[dirknerkle]

If it's either 0 or 90 and no need inbetween, wouldn't a simple solenoid work out? Simple, quick, firmware-free...:rolleyes:

[ErnieHorning]

All I was thinking of was a gear reduction motor (probably need to do this with a stepper too) and a switch on each end to kill power in that direction.

Think of a cam with a 90˚ pie cutout and a double throw switch inside. You could tap a screw hole on each side so that you could adjust exactly where it stops.

This is exactly how air handling dampers are controlled in buildings and homes

[Entropy]

For multi-unit approaches:

http://www.arduino.cc/playground/ComponentLib/Servo
http://www.ladyada.net/make/mshield/use.html

However, for the described application, an Attiny25 plus AVR-GCC is a lot more lightweight. The nice thing about servos is that they have most of the control and drive circuitry built in, and just need a TTL-level pulse input for control.

http://winavr.scienceprog.com/example-avr-projects/servo-motor-control-using-avr.html could easily be ported to an ATTiny, and tweaked to use an "on/off" switch to select two angles instead of using the switches for "up/down" control.

http://www.societyofrobots.com/member_tutorials/book/export/html/25 does multiple servos controlled via USB.

Edit: Given the new info, I would say:
ATtiny25 + H-bridge chip (L293 probably?) + limit switches would do the trick

[Matt_Edwards]

I like the Windscreen wiper motor idea more now we know the application.
They are geared down nicely and have reasonable torque
they are pretty cheap
You just need limit switches.

[NORTHEASTER]

Wayne,
A 110 volt commercial washer dump valve motor would work for this. These motors are spring loaded to return to start position and stall at open against the spring. It will stay open as long as it powered. They have a built in gear box so the open and close is slow. 90 degrees of movement is the norm for these.
gary