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Anyone made a auto 4way/8way switching joystick?

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DaOld Man:

This might be a good application for the nutchip,
http://www.nutchip.com/progetti/stepper_en.htm
 however you would also need a driver for the stepper. A ULN22823A Chip might work, if the stepper is a unipolar.
Or a L297 driver chip.
Very interesting project.

Edit: what kind of driver does this use? It looks like it only has 3 wires. Most have 4 or 6 and a few have 8.

Edit again. The one on deal extreme is a servo not a stepper.

Looks to me like the best thing would be limit switches to tell the driver that the motor is at one end of it's run. Unless there is a some type of feedback position encoder then it could easily get lost. (power failure while moving).
Position feedback encoder could be complicated and expensive. My advice would be cheap micro switches.

ranma:


--- Quote from: DaOld Man on September 08, 2010, 03:34:11 pm ---
Edit again. The one on deal extreme is a servo not a stepper.


--- End quote ---

yes, it's a servo, someone asked what was used on the example on this thread and that's what I've used. Driving a servo is very easy, using just a 555 and this allowed me to control both servo positions with a simple scroll lock on and off positions.

mgb:


--- Quote from: danny_galaga on September 02, 2010, 08:19:59 am ---
--- Quote from: mgb on August 31, 2010, 08:34:16 am ---The stick and restrictor plate are two different parts so there shouldn't be any issue there.

Just a thought but I wonder if muscle wire would work (though a little more pricey). Muscle wire is used in robotics, its a length of wire that retracts (like a muscle) when a voltage is applied to it.
I've never used it and I don't know how far the travel is but I wonder if it would work.

--- End quote ---

Would it be cheaper than a 5 buck servo?

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No it wouldn't be that cheap, but most servos are more $5

DaOld Man:


--- Quote from: ranma on September 08, 2010, 11:44:59 pm ---yes, it's a servo, someone asked what was used on the example on this thread and that's what I've used. Driving a servo is very easy, using just a 555 and this allowed me to control both servo positions with a simple scroll lock on and off positions.

--- End quote ---

Got a schematic or wiring diagram?

RandyT:


After playing with servos for a bit, I can say that I wouldn't be comfortable with the cheapest servo in the world when used in this application.  Contrary to what has been stated here, the joystick can, and does, move a restrictor out of position without something beefy holding it in place.  And a servo connected to one is very adamant about putting it where it thinks it should be.  That means that there are always opposing forces at play when in use, and whatever servo one uses needs to be up to the job of keeping the restrictor in position, and not overheat, strip gears, etc... 

It also has to be strong enough to overcome any type of random resistance that might occur, and have a "fail-safe" of some nature to protect the motor.  Nothing kills a servo faster than it wanting to move someplace where it isn't allowed to go.  This type of situation will be similar to turning on a DC motor at full speed, but constantly putting more resistance on the shaft than the motor is designed to handle.  It doesn't take long for it to overheat and die.  I've also seen them get into an "oscillation" situation where they flutter between two adjacent positions.  As they are constantly drawing a decent amount of current when this happens, it eventually causes them to overheat.

So basically, what I have found is that it can be done fairly well, but the "cheapest and easiest" route probably will not be the best approach.  The cheapest servos won't last too long and the simplest circuits have no way to protect the motors.

RandyT

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