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Comments by Jan
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New products: Magnetic quadrature encoders for micro metal gearmotors
- 3 October 2014That sounds great; thanks.
- Jan
New products: Magnetic quadrature encoders for micro metal gearmotors
- 3 October 2014We have evaluated many gearbox suppliers, and the ones we use are the best we know of. We would definitely like to hear more about your tests; can you provide us with more information about your setup? You could email us if the comments here on the blog are not convenient for getting into details.
- Jan
Thoughts on Open-Source Hardware
- 1 October 2014If you want to have a meaningful discussion, please be more specific about what you are complaining about.
If you are talking about our Maestro servo controllers, it seems like you might not be aware of the Pololu USB SDK, which has example code that shows how to use the Maestros' USB interface. Although the code is written in C#, you can use it as a reference for developing your own code that talks to a Maestro in the language of your choice. Many of our customers have done this, and you can see several examples in the "Related Resources" section of the Maestro User's Guide.
- Jan
Thoughts on journalists checking drafts with sources
- 8 September 2014In the most extreme cases, the wrong information, whether intentional or not, could lead to things like war. Even in more mundane situations, impressions journalists give the public can have significant repercussions for things like allocations of permits or public funding, which can impact a community with things like creation of jobs or improvement of safety or eradication of a nuisance.
To bring it back to Richard's example of not caring about the impact his writing might have on a manufacturer ("I'm not interested in their profit margins"), I say we should care if our mistakes bring economic damage to others. And while Richard might think that it's not his or his readers' problem if some product doesn't sell or some company goes out of business, what he is leaving out is the cost of his being wrong. In this case, it would mean that a good product stops being available or a company making good products stops existing, which is bad for more than just Richard's readers. I doubt that writers like Richard actually want to be responsible for this kind of outcome, but my suspicion is that they are blinded by reckless arrogance.
- Jan
Thoughts on journalists checking drafts with sources
- 8 September 2014Hello, Richard.
I appreciate your posting since it gives us a specific instance of this journalistic haughtiness I think is very damaging. Manufacturers of products you review are a little different than the kind of information "source" I was talking about, but what I think are the flaws in your mentality are the same. I don't know you or your writing (though for all we know, I might have read some of it), so I am going just off of the comment you posted here.
The only reason you gave for defending your position is "it can stifle the right to freely comment". I do not believe this, and the comment from Aeroengineer1 indicates it is possible to maintain the independence of your commentary while having facts checked. Journalists should exercise their integrity by considering feedback from interested parties, not by sticking their heads in the sand. Regarding your SparkFun example, you seem quite content not to care about my response after publication, so why would you care so much about upsetting me prior to publication? If I give you some factual feedback because I am upset, does that invalidate those facts? Are you not able to evaluate my claims of fact just because I have a bias?
The rest of your comment is full of the arrogance I was originally commenting on in this post. You think that there is some virtue in your consequences be damned attitude just because you claim to be serving your readers. Journalists, like everyone, should care about the adverse consequences their mistakes could have on the broader community, not just some subset they decide is all that matters. I am not at all saying you should be some corporate shill, but part of taking responsibility for your work is caring about its consequences. Furthermore, it does not serve even your readers for you to artificially limit the validity of your writing just because you think your own analysis is good enough.
To be clear: I am not at all arguing against your right to have an opinion or to publish an opinion. What I am saying is that your claim that "I come to my conclusions after careful and considered deliberation" is quite disingenuous if you do not avail yourself of easily available feedback (even if it's from biased sources).
I am quite curious about what problems you are talking about when you say "On the occasions it has happened (without my consent), it has caused nothing but problems." If all those problems were like what you continued to present for most of your comment, I really don't see the validity at all: it sounds like some people were ticked off, which they probably would have been after your publication, too.
I am not the one arguing for some extreme, such as that every article should be pre-approved by sources or that you have to make your sources happy. I think most reasonable people can immediately imagine scenarios where other considerations outweigh the benefits. What I continue to believe is that arguing that such draft checking is almost never appropriate significantly undermines the credibility of journalists.
- Jan
Simple hardware approach to controlling a servo
- 3 September 2014David,
I am not sure what is typical. I suspect sequential pulses are more common for cheaper and lower channel-count units, but eventually, the pulses have to overlap if there are enough of them. When we develop products such as the TReX, we make sure that they can read all the channels no matter what their relative timing might be.
- Jan
Understanding battery capacity: Ah is not A
- 3 September 2014Billbo,
You should be able to do the calculation if you read the blog post and comments (did you?), but here goes:
``"4 minutes"/"time" * ("6 times")/"day" * "7 days" * "1 hour"/"60 minutes" = "2.8 hours"``
We can round that up to 3 hours and if we go with your upper limit of 600 mA, you would need:
``"600 mA" * "3 hours" = "1800 mAh" = "1.8 Ah"``
Keep in mind that this is just for the motor for the duration you specified; if there is some electronics that's on all week controlling when the motor turns on and off, you'll have to factor in how much energy that will need.
- Jan
Understanding battery capacity: Ah is not A
- 17 July 2014Tyler,
Your post looks sloppy and lazy, making it difficult for anyone to help you or to want to help you. For instance, I suspect you are not actually trying to run a 12 V cell-phone charger off of your phone battery. But even if I assume you want to make a portable power pack into which you can plug in your phone charger, I still cannot really understand your question. What are you trying to achieve? Why do you care about efficiency? Typically, in an energy conversation, the relevant efficiency is how much energy you spend charging your power pack vs. what you get back out of it, but it seems like you might care more about being cost efficient or size efficient.
- Jan
Understanding battery capacity: Ah is not A
- 23 June 2014Jun,
It is not appropriate to think about an "is it okay" question based on the specs you have given. You can use the current and voltage specifications of the chargers to get a rough best-case estimate of how long it will take to charge the batteries, but whether it will work at all or be safe is a completely separate issue. You should only use chargers that are specifically made for your kind of battery pack (and you should make sure you know how to configure them appropriately).
- Jan
Electrical characteristics of servos and introduction to the servo control interface
- 16 June 2014Sorry, I am not familiar with those Kyosho 4-wire servos. By the way, once we are dealing with a proprietary system like this, we don't know what the first 3 wires are, either (though power and ground are good guesses for two of them). If you (or anyone else reading this) have a broken one that you would be willing to send in, I would be happy to take a look at it.
- Jan