Posts by Jan (Page 4)

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Force and torque

Posted by Jan on 31 December 2010
Force and torque

I got a few private requests for more information about torque after my post on units, and since torque is relevant to the next few posts I want to make about servos, I’ll try to explain torque a bit more today. Torque is intimately connected to force, so we’ll start with a review of Newton’s laws of motion. You should know some basic calculus to really understand these concepts, but getting into that is beyond the scope of this post; I hope I hit the right level of simplification to provide some useful knowledge to those who have some basic intuitive mechanical sense but have not taken, or have forgotten, basic physics courses. Continued…

More LEDs

Posted by Jan on 23 December 2010
More LEDs

With Christmas just a few days away, and having just discussed a single LED circuit and simple parallel circuits, I’d like to make a few comments about using multiple LEDs. I’m still talking about basic LEDs, and not too many of them; for specialized LEDs or large arrays, there are all kinds of chips designed just for that. Continued…

Parallel circuits

Posted by Jan on 17 December 2010
Parallel circuits

If you have a limited or informal electronics education, parallel circuits might be the kind of topic you glossed over or have forgotten about. After all, parallel circuits sounds like boring theory, and you want to get to the fun stuff. But, banging your head over a simple system that you think should just work isn’t much fun, and you can save yourself a lot of grief with a bit of awareness about the potential differences between a schematic and a physical circuit. Also, I’m a proponent of learning fundamentals and trying to really understand things, so we’ll start with a bit of the basic theory. Continued…

Simple LED circuit abstractions

Posted by Jan on 8 December 2010
Simple LED circuit abstractions

The simple LED circuit from last time is a great first circuit for everyone interested in electronics because it is so forgiving. If you connect something backwards, you probably won’t break anything, and otherwise, it should just work. However, that forgiving nature of the circuit can beguile newcomers into thinking everything is that simple, and though there are many web pages out there discussing the circuit, they usually do not address the abstractions and simplifications that are in play and why we can use them in this instance. So, that’s the topic for this post. Continued…

Simple LED circuit

Posted by Jan on 30 November 2010
Simple LED circuit

One of the simplest circuits you can build is an LED powered by a battery. Unfortunately, many people who think they know some electronics (and even multiple job interviewees with supposed electrical engineering degrees) cannot actually draw the schematic for the simple circuit or calculate the appropriate component values. Can you? Continued…

Abstractions

Posted by Jan on 24 November 2010
Abstractions

We should consider the general concept of abstraction in robotics a bit before moving on to more specific topics. Abstraction comes up a lot in computer science and programming, so I think people in that field are exposed to it early and often. Just about any program will have at least some user-made abstractions in it, be it a data structure or a subroutine, so programmers tend to be aware that the abstractions are just whatever they choose to make them and that they are not necessarily statements of absolute fact. In other introductory engineering contexts, at least in my experience, there is less of an explicit acknowledgment of the abstractions being used. Continued…

What's in a name?

Posted by Jan on 22 November 2010
What's in a name?

At the risk of sounding like I’m telling you to eat your vegetables, I’m going to zoom out one more step from the last post about units and talk even more generally about the importance of names. Whatever you think of Juliet’s famous answer, the reality is that if you want to get someone a rose, or even just to talk about a rose, you need to know what it’s called. Naming things is a very powerful human skill that allows us not only to better communicate our thoughts but to better form our thoughts in the first place. Continued…

Know your units

Posted by Jan on 19 November 2010
Know your units

How many volts of current are there in a bolt of lightning? That’s the kind of stupid question your local news anchor might ask while bantering with the weather guy. Perhaps your favorite cringe-inducing unit abuse is someone thinking light-years measure time or a model rocket enthusiast telling you that a newton-second is a little longer than a regular second. Of course, I made the same class of mistake when looking for a 1-amp battery, which I described in my previous post about battery capacity. That article addressed a specific instance of a general problem: not knowing or understanding units, which allow us to talk about and measure physical properties that we must understand whether we’re designing robots or baking cakes. Continued…

Understanding battery capacity: Ah is not A

Posted by Jan on 12 November 2010
Understanding battery capacity: Ah is not A

My earliest electronics projects and my first robot were powered by regular alkaline batteries, and I didn’t think about current or the capacity of those batteries. The batteries were prominently labeled “1.5V”, and I was happy in my understanding that putting four in a battery holder got me to 6 volts; when the motors slowed down, it was time for new batteries. When I began designing my second robot, I found some 12V, 1A motors (what a “1-amp motor” might mean is a topic for another post) and promptly wasted many hours dragging parents and teachers to Radio Shack and car parts stores looking for a 12V, 1A battery. Continued…

Introduction to Jan's blog

Posted by Jan on 12 November 2010
Introduction to Jan's blog

My name is Jan Malášek, which is a Czech name, so the “J” is pronounced as an English “Y” (if you care, we can go over the last name in person, or you can consult your local Czech person). I grew up on the Big Island of Hawaii, spent five years in school in Massachusetts, and then moved to Las Vegas, Nevada to work on Pololu. I recently turned 30, and I’m still not the millionaire I had hoped to become at age 23 and then by age 25. Hitting 30 means it has been twenty years since I got started with electronics and ten years since I routed the first circuit board that said “Pololu” on it. Continued…

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