Re: Motor Control - 3 Position Start-Stop
- From: Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@xxxxxxxxxxx>
- Date: Sun, 04 Mar 2007 11:40:25 -0500
alokw wrote:
Hi Anthony,Ah, that reminds me. you could use a Voltage Comparator and have a
Thanks for your quick reply!
I did some research from the information that you sent me and had a
few questions. These are mostly due to my lack of knowledge with
electronic components.
I was able to find most of the parts, but couldn't find any 390nF or
100nF capactiors. I was able to find 390uF and 100uF, but I assume
there is a difference between the two. Also, the diagram specs a "2K7"
resistor and potentiometer. Is this short for something? I couldn't
find anything with those labels.
Is there a really big "amazon.com" of electronic components that I
don't know about? Where do you usually get your components?
Also, I wouldn't be opposed to using a PIC, but I wouldn't know where
to start. Are there any great benefits to using a PIC?
Thanks so much for your help!
-Alok
On Mar 4, 6:39 am, "Anthony Fremont" <spam-...@xxxxxxxxxxx> wrote:
alokw wrote:
Hi all!
I'm working on a small project which requires an automated disc to
rotate and stop in 3 positions.
Basically, I have a small 8" disc made of foamcore, which I need to
attach a small motor to. I am familiar with DC wiring and have used
motors like this before, but have never had the need to do anything
more complicated than reversing the polarity.
What I'd like to do, is have some kind of controller, ideally, with
three buttons. When I push button 1, the disc rotates to 120 degrees
from its home position. When I push button 2, the disc should rotate
to 240 degrees from its home position. When I push button 3, the disc
must rotate back to its home position.
Obviously, since the disc is only 8" in diameter, the mechanism will
have to be relatively small. I'm also on a low budget, so whatever I
can do to save money will be useful.
Any ideas or suggestions will be greatly appreciated, as I'm not sure
where to go from here.
Sounds like you could use a servo motor from a radio controlled plane or
car. They respond to pulsed signal. By feeding pulses of varying widths to
the servo, the servo can be made to turn to a certain position and stop.
These pulses fall in the range of 1mS to 2mS with 1mS causing the servo to
move all the way in one direction and 2mS moving it to the other limit.
Widths in between will make move the servo to a proportionate location.
All you have to do is be able to generate 3 different pulse widths and
switch between them. If you search for 555 and "servo tester" using Google,
you will find sample circuits to drive servo motors. Here is one:http://www.uoguelph.ca/~antoon/gadgets/servo3.htm
If you want to "use a PIC" instead, just say so. ;-)
continuos potentiometer on the shaft.
You just need three different voltage levels to select from. the
output of the comparator would drive the motor one way or the other
to balance the position of the disc.
Using 2 comparators in a bridge mode to drive the motor.
actually, 2 op-amps driving a dc bridge to position the motor will help.
Just position the pot so that the cross over point is is between one of
your selections.
--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
.
- References:
- Motor Control - 3 Position Start-Stop
- From: alokw
- Re: Motor Control - 3 Position Start-Stop
- From: Anthony Fremont
- Re: Motor Control - 3 Position Start-Stop
- From: alokw
- Motor Control - 3 Position Start-Stop
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