Questions on Parallax Continous Servo's

Rich_W8VK

Hello All!
···· I have 2 projects that·requires·one Parallax Continous Servo for each project!

Project 1
··· Is it possible to use this servo to turn Both ways·with a·limited 10 turns at 1 degree increments with a BS2? And to log the Current Servo Setting to memory so the position is known, and can be recalled·at·any later time?

Project 2
··· Is it possible to use this servo to turn both ways but a limited 300 degrees? (Less than 1 revolution) and at 1 degree increments? ( I don't want to use the Parallax Standard Servo because of the need for continous pulses to maintain position and position jitter!) Could this position also be logged to memory to be referrenced later?

Thanks for reading my post!

Rich

Franklin

Project 1 -- No.
Project 2 -- No.

You probably would be better off with stepper morors and gears.

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- Stephen

Rich_W8VK

Ok Steve!
····· Appreciate the suggestion! I will read on Stepper Motors and see if it fits the bill! Seasons Greetings to U too!

Rich

P!-Ro

You could do it if you used a rotation counter, but it will take extra hardware.

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PG

Rich_W8VK

Hi PG!
···· Thanks for your thoughts! I've used rotation counters on Ham radio Stuff!
It appears my thoughts on this Servo subject aren't anything like another method I'm presently using! Sounds like it's time to·scrap these ideas! Thanks to all that replied!

Rich

W9GFO

There are servos that will rotate multiple turns but are not continuous rotation. They are called sail winch servos. Some of them will rotate a full 4 rotations.

You could also modify a servo by replacing the standard pot with a multi turn pot.

However, as far as ten turns with one degree increments - no. That would be 3,600 unique positions. If you used a servo that worked with .500mS to 2.500mS pulse widths (typical is 1.000mS to 2.000mS) AND the servo had a dead band of only 1uS (typical is 4uS to 6uS) that would still only be, at best, 1,000 discrete positions.

Rich H

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The Simple Servo Tester, a kit from Gadget Gangster.

Rich_W8VK

W9GFO,
···· Thanks so much for showing and explaining to me about the servo's!
I now see that i can't do either project with a Servo! Seasons greetings to you too!
73's

Rich_W8VK

·

RogerN

You can do what you are describing but you need additional hardware, or you could do it with a Basic Stamp if Slow was acceptable. One possible way is to program a microcontroller to read a shaft encoder, provide pulses to the servo, and communicate with the Basic Stamp. Then you could send a move command out with the basic stamp serial and the microcontroller would take care of the rest. The servo with 300 degree output could just use an external pot geared to rotate 300 degrees. Of course there are existing servo controllers that could be set up to use as you describe but most are quite expensive. The cheapest would probably be some of the hobby CNC stuff, a Gecko servo drive can use a servo with encoder feedback and take step and direction signals from a Basic Stamp, I don't remember the exact specs but I think the Gecko servo drive can run up to around a 1 HP servo motor (something like 20A (Peak?) at 70 - 80V).

If you were going to do this with just a Basic Stamp then you could get an encoder and move slow enough that you don't miss counts. If you have no other tasks while moving you could continuously read the encoder and keep up at a reasonable speed. For example if you had an overhead maximum of a 2ms servo pulse plus 2ms worst case of reading encoder and updating position counter, you could count 250 degrees per second.

RogerN

Rich_W8VK

Ok RogerN,
···· Thanks for the post! Seasons Greetings!


For all readers at this point, I will NOT be answering anyone anymore as this is not a good way to do what I wanted to do!

So no more posts Please, as I can't delete this Topic! Thanks to all!


Rich
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