We (Karl Lunt, Bill Harrison, Keith Payea, and myself and perhaps other SRS folks I can't remember) built a display for the Pacific Science Center back in...
47558
David Buckley
robots42
Feb 3, 2013 6:50 pm
The problem with brushless motors is you need fancy controllers, easy if you are in the hobby/model world but not as common and more expensive in the...
47559
Chuck Harrison
c_f_harrison
Feb 3, 2013 8:12 pm
Michael, One good thing about your application is that (I presume) it is low duty cycle -- an organ only gets played a few hours a day and probably only a few...
47560
Randy Carter
randycarter2001
Feb 3, 2013 8:18 pm
The key to know the message is bogus and a future problem is to look at the recipients list. This message had several recipients. It looks like the message...
47561
Pete Miles
ajklz5
Feb 3, 2013 10:53 pm
Well, here is my 0.00002 cents worth. If you are expecting R/C servos to be reliable, then prepare to be greatly disappointed. They are not, and have never...
47562
Mark Kenworthy
kwmachine
Feb 3, 2013 11:07 pm
You might want to ask the same question of the Seattle Metalheads Yahoo group. There's a fair amount of expertise on that list running stepper and (CNC type)...
47563
David Buckley
robots42
Feb 4, 2013 12:12 am
If you buy a professional lever actuated pot such as is used on golf carts, and mobility chairs, or an industrial quality servopot (~$15) you won't have to...
47564
Rob Purdy
gausswave
Feb 4, 2013 12:59 am
lol Speaking of metal heads....I just up at Andy's place today and I brought this up. First words out of his mouth was linear motor. Funny thng was I was...
47565
km6vv
Feb 4, 2013 2:23 am
sorry for the duplicate post. Anyone seen an application for an iPhone to allow me to do serial read of my u-Blox 5 GPS? I need a highly portable (and...
47566
SeattleRobotics@yahoo...
Feb 4, 2013 3:01 pm
Reminder from: SeattleRobotics Yahoo! Group http://groups.yahoo.com/group/SeattleRobotics/cal Monday Night Chat Monday February 4, 2013 7:00 pm - 9:00 pm ...
47567
SeattleRobotics@yahoo...
Feb 5, 2013 2:01 am
Reminder from: SeattleRobotics Yahoo! Group http://groups.yahoo.com/group/SeattleRobotics/cal Monday Night Chat Monday February 4, 2013 7:00 pm - 9:00 pm ...
47568
David Wyland
dcwjobs2004
Feb 5, 2013 4:12 am
A note on servos, brushless DC motors and stepper motors. Brushed DC motors, such as those used in RC servos, have finite life due to brush wear. With proper...
47569
K Maxon
k_maxon23
Feb 5, 2013 6:33 am
  Hi Guys, a general question:  Have any of you used the cheap import version of the SRF-04 sonar module, the HC-SR04) I have used the standard...
47570
hesperion22
Feb 5, 2013 9:17 pm
I agree that the longevity and reliability of these servos is a real concern. I am studying your suggestions and alternatives. Being green at this I am having...
47571
hesperion22
Feb 5, 2013 9:28 pm
Thanks Dave for those links. This had occurred to me as well (i.e.; steppers, brushed/brush-less) I am intrigued also that there is the possibility of speed...
47572
Rob Purdy
gausswave
Feb 5, 2013 9:39 pm
Andy Is up near Duvall. Linear motors are typically used in CNC machines. That's a good place to start. They're basically like a DC motor that 's unrolled if...
47573
hesperion22
Feb 5, 2013 9:40 pm
Thanks Pete, Good points ALL. Of course failures are not a good thing but we have to see them as opportunities as well. A reasonable lifetime is what I am...
47574
Rob Purdy
gausswave
Feb 5, 2013 9:40 pm
It's a hobby forum... welcome to the beginning. To: SeattleRobotics@yahoogroups.com From: drownedviola@... Date: Tue, 5 Feb 2013 21:28:08 +0000 ...
47575
ListServ
theear1
Feb 5, 2013 10:24 pm
Would the vanes stay in place if you removed the actuator force? It seems to me that the swell is only adjusted 'occasionaly' and would not need to be active...
47576
hesperion22
Feb 5, 2013 10:38 pm
Yes between adjustments of the shades they would have to hold position. I would also prefer they stayed in the last position they were when power is cut,...
47577
hesperion22
Feb 5, 2013 10:40 pm
Thanks, I will seek some info on this. I know they are used to run trains. That, I suspect, might be a bit more than I need. In a small scale application...
47578
James Hughes
jamezilla123
Feb 6, 2013 12:11 am
... I was not aware there were stepper drivers that could microstep down to 1/256. Most of the stuff out there is 1/10. Can anyone recommend a good brand? ...
47579
Rob Purdy
gausswave
Feb 6, 2013 12:18 am
Start with Geckodrive.com The white pages Mariss wrote should be required reaqding for any one gettinginto CNC. That noise can be mitigated many ways but...
47580
James Hughes
jamezilla123
Feb 6, 2013 12:37 am
I'm familiar with Gecko, but all of their drivers are 1/10 uStep at the finest setting. I was specifically curious about 1/256 uStep because it gets you to a...
47581
km6vv
Feb 6, 2013 12:57 am
I wouldn't worry about 1/256. You can't use it anyway. It's for killing the resonance bands in the stepper (makes for smooth acceleration). 1/10, you may be...
47582
Chuck Harrison
c_f_harrison
Feb 6, 2013 3:04 am
@James I would not discount 256X microstepping as being unusable for positioning precision. My first experience with microstepping was in the '80's with a...
47583
Rob Purdy
gausswave
Feb 6, 2013 3:18 am
How accurate do you need those steps to be? @ 256 steps you will see some vaiance due to inaccuaracies in the motor build. There's also some torque loss....
47584
Chuck Harrison
c_f_harrison
Feb 6, 2013 3:18 am
Re: Hi-res microstepping... The industrial hi-res stuff is pricey. If you are a hardware guy, you can build something with the L6470 by ST Micro (a one-chip...
47585
David Wyland
dcwjobs2004
Feb 6, 2013 7:58 am
Micro-stepping can be done by doing a PWM of the current drive to the two active coils. The PWM alternates the current between the two coils. If the PWM is...
47586
James Hughes
jamezilla123
Feb 6, 2013 8:11 am
Lots of great info guys! The ST L6470 looks pretty amazing for single axis applications. You just give it a position, and it generates the acceleration curves...
