Sunday, February 19, 2012

Why I Just Unfollowed 60 People

This is just a brief note to explain why I just unfollowed 60 people on twitter. I follow people in the first place for the following reasons: I have a personal connection, I would like to 'network', someone is funny, or someone is unusual or interesting in some way. I basically want to hear about what is happening with all the people I have ever followed.

But I can't keep up. With anyone. Following additional people reduces the average attention I can give each person (my attention is not constant, but has a maximum). I had hit the point where I did not have the quality level of attention to make twitter value for me.

So I brutally unfollowed half of the people on my list. This isn't an act of rudeness, it is an attempt to restore the connection I have with at least some people. If have unfollowed you, and you notice, and you'd explicitly like me to continue to follow you, please do let me know. I will more than happily re-follow people who would like to maintain the connection.

I'll also add: if I had better ways of managing and filtering posts, I would be very happy to follow many more people once again. I still think the internet needs an awesomeness filter :)

Wednesday, February 8, 2012

Understanding a transistor (hint: I don't)

Right, so I have set up a circuit. I'm afraid I'm not much with photoshop, so here's a worded description.

5V+ is wired into what I think is the collector
An Arduino output pin is wired through a 330 Ohm resistor into what I think is the base
The emitter is wired to a connection point
5V - is wired to another connection point
My Arduino is programmed to emit a HIGH pulse for 2 seconds every 2 seconds to the base.

Using the volmeter to complete the circuit and measure the volts saw a change every 2 seconds as expected. However, it was measuring 1.5V, then an increase to 3.4V and back again.

Can someone please explain why the voltage doesn't drop to zero?

Then, for bonus points, why does it not reach 5V? I can accept that the HIGH level might not be quite 5V for a variety of reasons such as the Arduino itself using some power from its source, some current going towards the base which is then not available to the 5V output from the Arduino etc etc.

But why on earth is there 1.5V present when the transistor's base recieves no current???

Now, for the next question. If I detach the wire from the Arduino output pin to the transistor altogether, the circuit from 5V to collector to emitter measures 3.3V! Surely in this case it should be either 1.5V (as per above) or 0.

I just don't get it!

Sunday, February 5, 2012

Resources and tips

In working on this project, I've hard to source my own resources for learning. As a software guy, my hardware knowledge is limited to whatever I can still remember from high school physics, which is 15 years ago now. Granted, I don't seem to need much more than high school physics here, but 15 years is a long time between study sessions.

I discovered that a great many electronics books are structured as follows: fluffy introduction, definition of all terms, history of physics, all of physics, now do it. Unfortunately, I can't assimilate knowledge that way. It's impossible (for me) to integrate an abstract set of definitions and history lessons, and come out with a working knowledge of building circuits. It's hard just to get through the introduction without falling asleep, frankly. So here is where I go:

Book: "Make: electronis: learning by discovery"

This video series, an intro to circuits from the absolute, total beginning; by Bucky Roberts:

This video series, specifically covering the Arduino, by Jeremy Blum:

I'm sure I'll end up assembling some more resources as I learn and need more advanced topics, but these constitute a really great start with a gentle learning curve.