Comments by Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 31 August 2012

    Did you read the post? Anyway, 2000 mAh should last about 1 hour at a 2 A discharge rate, 2 hours at a 1 A discharge rate, 10 hours at a 200 mA discharge rate, and so on. Typically, the capacity is based on some particular discharge rate, and capacity will be lower if you discharge faster than that. By the way, a modern cell phone battery is going to be a lithium-based battery, which you have to be extra careful not to over-discharge, and the battery module might have some integrated electronics to protect and monitor the battery.

    - Jan

  • Ten years in Las Vegas

    Ten years in Las Vegas

    - 25 August 2012

    Charley,

    Thank you for your kind words. I think we still have a long ways to go before we are a "really great company", but we're working on it!

    - Jan

  • Why we don't have comments on our product pages

    Why we don't have comments on our product pages

    - 25 August 2012

    Tomek,

    Thank you very much for your feedback. At this point, I think that if I could just flip a switch and have comments in a way that would not be that objectionable (for instance, with some of the suggestions you had), I would turn that feature on. The way we're organized right now, though, our few web programmers are also involved in product design, and I would rather spend our time on new products or on more important features for the web site (such as the search system).

    - Jan

  • Introduction to servos

    Introduction to servos

    - 20 August 2012

    Ivan,

    Did you look at the post about multi-turn servos?

    http://www.pololu.com/blog/24/continuous-rotation-servos-and-multi-turn-servos

    In general, it's pretty difficult to change a normal servo to a multi-turn servo; at the very least, you need to change your feedback potentiometer to a multi-turn pot or change the gearing to it somehow.

    I do not know what you mean by the "in one direction" part. If it can go more than 360 degrees and keep track of position, it will be able to do that in both directions.

    - Jan

  • Advanced hobby servo control pulse generation using hardware PWM

    Advanced hobby servo control pulse generation using hardware PWM

    - 10 July 2012

    Hello.

    This article is about using one PWM source to get multiple servo control signals. As I said in the post, I think it is not helpful to think of servo control pulses as general PWM signals. You cannot get four arbitrary PWM signals out of one PWM signal.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 18 June 2012

    Hello.

    Your basic math is right, but keep in mind that capacity depends on discharge rate, so depending on the battery and how it's rated, it might not necessarily give you the 4320 mAh if you discharge it at 4.3 A. We do not carry any packs with that high of a capacity, but that's in the range of what you would get with "C" sized NiMH cells. You should be able to find receiver or servo packs with that kind of capacity at a hobby store (a quick search at Tower Hobbies led to http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVTG1&P=7 ; at first glance, it might be what you're looking for). You could also consider lead-acid batteries; they will be bulkier, but they will probably be cheaper and easier to find in capacities exceeding 4Ah.

    - Jan

  • Three and a half months to plug in our machines legally

    Three and a half months to plug in our machines legally

    - 29 May 2012

    Pete,

    I am not suggesting that "qualified and accountable" people should not be involved. However, I think that government should not have a monopoly on safety standards and that the existing government monopoly leads to sub-optimal results (just look at the post above yours for an example). For instance, we could have facilities rated by some private company, and employees could choose whether to work in a place that was not rated or had a lower rating than they were comfortable with. Your insurance example shows yet another way the private market incentivizes safety. (And doesn't your suggestion of going to the insurance company indicate that you think the private company might have been more effective than the government?)

    - Jan

  • Three and a half months to plug in our machines legally

    Three and a half months to plug in our machines legally

    - 29 May 2012

    Daniel,

    Thanks for that perspective. I am generally in favor of leaving room for discretion, but that leads to more room for abuse because of the government's monopoly. If we instead had private inspections (which the county basically deferred to, anyway), there would be a little more room for alternatives if one particular inspector were being unreasonable.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 29 May 2012

    The discharge rate could be an issue, so that's one reason going with 15Ah is probably better. However, the higher capacity battery could be an issue for the charger, depending on how that works. But 14 is pretty close to 15, so I would just go with the 15Ah. I would be very surprised if the 12Ah didn't work, though, so if that somehow fits better or is much cheaper, it should be fine (don't forget the 15 will give you 25% more run time than the 12).

    - 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

New Products

RoboClaw 2x5A Motor Controller (V5)
Screw Terminal Block: 2-Pin, 0.1″ Pitch, Side Entry (4-Pack)
Pololu Dual MC33926 Motor Driver for Raspberry Pi (Assembled)
75:1 Micro Metal Gearmotor HPCB
Hakko T18-D24 Soldering Tip
Hakko PN-2002 CHP 5-7/8 in. Needle Nose Pliers
Screw Terminal Block: 7-Pin, 0.1″ Pitch, Side Entry
Hakko T18-D16 Soldering Tip
Screw Terminal Block: 5-Pin, 0.1″ Pitch, Side Entry (2-Pack)
1000:1 Micro Metal Gearmotor HPCB
Log In
Pololu Robotics & Electronics
Shopping cart
(702) 262-6648
Same-day shipping, worldwide
Menu
Shop Blog Forum Support
My account Comments or questions? About Pololu Contact Ordering information Distributors