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Looking to control a motor position using a variable resistor and Arduino uno - it is not a servo? Answered

I am a Radio ham and want to upgrade my rotator to electronic control instead of switches see http://www.qsl.net/zl1bpu/MICRO/ROTATOR/KR-400%20Schematic.gif as to what im trying to control - Need to create a c  programming type to make it simple

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steveastrouk (author)2011-12-18

What do you mean by "electronic control" in this context ? The link you posted, you have a display, and manually adjust the position to get the position you want.

If you want to aim and forget, you have a servo.

Steve

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m8 (author)steveastrouk2011-12-19

Im aiming to control it eventually using Arduino Uno and USB port Its just Im trying to write a class in 'C' so i can say - go to a position in degrees and it translates it to a resistance to monitor for on an analogue port.

Also see http://www.geekshed.co.uk/bxf-azimuth-rotator-controller/

Mike

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steveastrouk (author)m82011-12-19

Neat project.

You may as well make it a servo then ! And you can use the arduino PID library to do it for you, except the final control is what we call "bang-bang".

You'd apply a fixed voltage to the feedback pot, and angle = measured volts/5 x 360 or somesuch.

Steve

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rickharris (author)2011-12-18

Then you will need some kind of position feed back.

You can get 360 deg pots or look up grey scale sensors.

Depending on how accurate you want to be a set of reed switches round the antenna might be enough,

The right way to do this is to change your motor for a stepper motor then you only need to mark one home position and then count steps to your desired place.

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m8 (author)rickharris2011-12-19

No the motor inside the rotator is a dual wound AC motor and has a pot that feeds back a resistance proportional to the direction.

Im aiming to control it eventually using Arduino Uno and USB port Its just Im trying to write a class in 'C' so i can say - go to a position in degrees and it translates it to a resistance to monitor for on an analogue port.

Also see http://www.geekshed.co.uk/bxf-azimuth-rotator-controller/

Mike

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