Comments by Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 27 March 2012

    Hi.

    Most NiMH chemistries will probably tolerate at least a few C discharge rate, so an AA should be able to deliver at least 5A, which is plenty for the motor you're describing.

    I have no idea what you're asking with this solar stuff, probably because you have little idea. Among your likely confusions: weight is not at all enough to tell us how much power you need, and getting more current available in your batteries is not going to force more current into your motor.

    You should not be putting batteries in parallel unless you really know what you are doing, which in this case you do not.

    Maximum, optimal, and safe discharge rates are completely separate. Any maximum rating better still be safe, and there will be a wide range of safe discharge rates. Optimal in terms of energy delivered will probably be around a few mA over a month, maximum could be 20A for a few minutes.

    - Jan

  • RC servo speed control

    RC servo speed control

    - 19 March 2012

    Have you read (and understood) these servo control posts at all? If you are serious about your question, please provide a little more detail about what you are trying to do.

    - Jan

  • Advanced hobby servo control using only a timer and interrupts

    Advanced hobby servo control using only a timer and interrupts

    - 2 February 2012

    Yes, the time between pulses will not be perfectly constant, but that does not matter. I think I wrote quite a bit about that in the earlier posts.

    - Jan

  • Introduction to Jan's blog

    Introduction to Jan's blog

    - 25 January 2012

    Dan,

    Thanks for the feedback. It looks like you are aware that this is not the most appropriate avenue for this discussion, so you might want to think about what prompted you to post here before trying to contact us some more conventional way. You do bring up two subjects that I think are worth discussing publicly.

    First and most directly addressing your comment, you got quoted a little over $500 for over 2500 identical little parts. A laser cutter is not necessarily going to be the most cost-effective way to do that kind of job, and if you have a better way of doing it, great: do it that better way. It's a similar situation with the competing quote: I don't think we promise being the lowest-cost option, but you might not be getting an apples-to-apples comparison since there are other factors like turn time, quality, support, etc. I'm not saying the cheaper options are necessarily going to turn out worse: I might have done your job for half or less back when I was running a laser out of my house. Still, a lot of your ire seems to be stemming from your disbelief about it taking four hours, and that does not sound that off to me.

    Second and more troubling is your resorting to complaining about greed, which seems all too popular lately. There's some rate at which things are worth it for us to do, and if that rate does not make sense for your application, don't go for it. There are probably things that you would not do for $100 but that you would do for $1,000; does that make you greedy (in some bad way)? You say, "Might as well get them all cut, right?"; isn't that the same greediness? It's fine for you to come back to us with your other quotes to make sure there wasn't some miscommunication about your requirements or to try to negotiate a better price, but it's not appropriate or helpful to stoop to that kind of name-calling. Also, you should want to work and interact with competent people, for whom "greedy" probably isn't a particularly meaningful word.

    - Jan

  • RC servo speed control

    RC servo speed control

    - 10 January 2012

    Hi.

    The Maestros should give very good, smooth outputs, so the jerkiness is probably because of the servo you're using or the load you have on it. You're probably effectively getting a situation like the one in the last two diagrams, where the commanded position is gradually changing but the servo responds in jerks either because it isn't very good or because you have so much load on it that it can't move until the error is quite big. Can you put the same servo setup on an RC receiver and slowly move the controls on your transmitter?

    - Jan

  • November 2011 update: new building, new machines

    November 2011 update: new building, new machines

    - 4 January 2012

    I want my office near Pololu Valley! We have customers on the Big Island, so it might be possible to see some of our products in action there (I remember hearing some talk of a robot club in Waimea a while ago, but I don't know what came of that). I don't think we have any distributors in Hawaii.

    - Jan

  • Simple microcontroller approach to controlling a servo

    Simple microcontroller approach to controlling a servo

    - 21 December 2011

    Hi.

    Some of my earlier posts about servos address your question. Some servos don't need the continual stream, but in general, you need to keep sending the pulses at about 50 Hz.

    - Jan

  • Continuous-rotation servos and multi-turn servos

    Continuous-rotation servos and multi-turn servos

    - 8 December 2011

    The main motivation is cheap, relatively easy control: you can use just a single I/O line on a microcontroller, and you don't have to deal with any power electronics to drive the motor. If you want a motor controller that is more than just an H-bridge that you might have to do a lot of work with, it's difficult to get that and the motor and gearbox for the ~$10 of a cheap servo.

    - Jan

  • Continuous-rotation servos and multi-turn servos

    Continuous-rotation servos and multi-turn servos

    - 18 November 2011

    Hello.

    The servo is not made for continuous rotation, and it rotating continuously is a sign that you are asking it to go beyond its limit, which could cause it to be destroyed. The standard 1-2 ms range should get you close to the full turn, and you can gradually expand the range while keeping it centered at 1.5 ms to get to exactly one rotation of range.

    By the way, you should direct questions like these to our forums or to more direct tech support.

    - Jan

  • Advanced hobby servo control pulse generation using hardware PWM

    Advanced hobby servo control pulse generation using hardware PWM

    - 18 November 2011

    Hi.

    I don't know how you expect me to be able to judge that better than you. However, from the little information I can get from your question, it sounds like you aren't getting the point. This article is about a specific approach to getting many channels of servo control. If you just need one or a few servos, you don't need anything this complicated, and if you need to do many servos, you're probably better off getting a dedicated servo controller.

    - Jan