[sudo-announce] Microcontroller Hacking begins in 48 hours!

[Scott Garrison]

I'd have to disagree on this one.  Servos have an encoder that allows the
motor to know it's exact position.  Stepper motors will miss steps and
won't be able to catch itself.  I guess this is an accuracy vs precision
argument as at least the stepper motor is stable in it's adjusted position.

If you are getting oscillations or wobbles in your position with a servo
then most of the time you are sending it a corrupted signal.  This happens
with microcontroller code whose servo libraries are not interrupt driven as
the PWM signal gets corrupted by other processes.  Or with unshielded
cables that are experiencing crosstalk from other wiring.

As with all things the hardware has to be matched with the job though.  If
your servo gears have lots of slop or aren't up to the job of positioning
something heavy they will struggle.  It's possible to use a potentiometer
as a secondary encoder of position to help if your gearing is introducing
extra error.

-=[Scott]=-


On Fri, Mar 29, 2013 at 2:37 PM, David Rorex <drorex at gmail.com> wrote:

> If you want ultra precise control, you need stepper motors. Or maybe
> really expensive servos would work, but the cheap servo's I've used are
> only accurate to a couple degrees and can wobble a little.
>
>
> On Thu, Mar 28, 2013 at 3:13 PM, Scott Garrison <
> scottrobertgarrison at gmail.com> wrote:
>
>> I'd be interested in doing something similar for controlling a camera.  I
>> also have an extra house satellite dish that I would love to put to use.  I
>> have experience controlling servos with microcontrollers.
>>
>> -Scott
>>
>>
>> On Wed, Mar 27, 2013 at 3:07 PM, Steve Berl <steveberl at gmail.com> wrote:
>>
>>> I notice on the etherpad that someone is interested in a 2 axis control
>>> for a radio dish. I'm interested in that also. In particular I want to
>>> mount a house satellite TV dish sized antenna on a 2 axis mount for radio
>>> astronomy use. It requires smooth and precise, but slow movement.
>>>
>>> Who is it that is interested in this project? Can you get in contact
>>> with me?
>>>
>>> -steve
>>>
>>>
>>> On Sun, Mar 24, 2013 at 5:43 PM, <hol at gaskill.com> wrote:
>>>
>>>> Howdy folks,
>>>>
>>>> We are two days away from the beginning of the second microcontroller
>>>> project hacking night at sudo room.  As someone suggested, I created a
>>>> facebookpage for the event.  Please invite people you think might be
>>>> interested!  I previously ordered 10 ATMega328p chips and crystals, and
>>>> will have them available at cost ($5) for those just starting out who want
>>>> a basic controller.
>>>>
>>>> Event Link:
>>>> https://www.facebook.com/events/502675869769339/
>>>>
>>>> Also, there is an etherpad to jot down projects you intend to work on
>>>> in case anyone out there is interested in collaborating:
>>>> https://pad.riseup.net/p/microbotics
>>>> This will be an ongoing document, and is intended to provide a
>>>> subsystem-level view of project elements in order to encourage people to
>>>> join together to work on individual elements or principles where interests
>>>> overlap in a way that permits a limited scope of collaboration, without
>>>> having to commit to recurring work on an entire project.
>>>>
>>>> We had some interesting projects last time and I expect even more this
>>>> time, hopefully with a few people from the last event returning to show
>>>> what they've done with their projects since then.  Personally I will try to
>>>> go back and forth between  50% working on 2-3 projects, 30% getting newbies
>>>> started on their controller builds, and 20% snacking/shooting the shit.
>>>>  Looking forward to seeing y'all!
>>>>
>>>> Cheers,
>>>> Hol
>>>> _______________________________________________
>>>> sudo-announce mailing list
>>>> sudo-announce at lists.sudoroom.org
>>>> http://lists.sudoroom.org/listinfo/sudo-announce
>>>>
>>>
>>>
>>>
>>> --
>>> -steve
>>>
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>>>
>>
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