Week 9: A return to electronics--setting up

As a kid, I used to spend a lot of time inventing and building electronic circuits. I could have told you immediately that yellow-violet-orange meant a 47 kilo-ohm resistor. Alas, those details have slipped into the murky depths of time, but I have regained an interest in electronics recently because I've seen how powerful and easy-to-use modern microprocessors are.

In particular, I've been looking into the Arduino microprocessor (shown right) as the core of a few applications I want to build. 

But before I leap into more complex projects, I want to re-acquaint myself with building electronic circuits again. All of my electronics gear is back in Australia so I needed to do quite a lot of shopping to get myself all set up again. After a very long time spent wandering the confusing aisles of Fry's (the handiest place for this kind of gear, even if not the best), I came home with quite a haul.

As a starting point, I just wanted to have a reliable 5V power supply available for building circuits. This should be easy (and is in hindsight), but it took a while to figure out precisely how to do it. I opted for an off-shelf power adaptor that has a switch to select voltages in 1.5V increments up to 12V. 

I grabbed a prototyping breadboard to build the circuits on, and a handful of components to have a properly regulated power supply. The cheap power adaptor has settings for 4.5V and 6V but nothing for 5V so I definitely needed to do something to give a reliable 5V supply. Of course, those settings are very loose as it is and if you measure the voltage across the supply without any load or a very small load, the actual voltage is much higher than that stated. 

The first problem was getting power from the power adaptor to the breadboard. I found a convenient socket for a power adaptor cord that I could attach a couple of wires to the back off and run them to the power terminals on the breadboard. That way I didn't need to hack apart anything in the power adaptor and I can still use it for other purposes.

With power to the breadboard, I just needed to regulate the voltage. The solution was the very convenient LM7805 voltage regulator (which only took me 20 minutes to find at Fry's because they have a supplier that relabels everything in some obscure code that I only deciphered once finding a full catalog).  You can essentially apply any voltage from 7-20 volts or so to the chip, and pull off 5V+/-0.25V. Add a few capacitors on the input and output sides of the chip to smooth out the voltage under load, and it's all set. 

Just to test there was power working properly, I just drove a single LED (via a resistor to avoid the characteristic pungent smell of frying electronics that I recall from undergraduate laboratory classes). And here is the result. As you can see, the LED is lit and my digital multimeter is showing a voltage of 4.99V. A perfect start to getting back into electronics.

Next was a simple circuit to make sure I have things working. Using the classic 555 timer integrated circuit, I decided to make a small sound generator. It produces a sawtooth pattern with the frequency depending on the values of resistors and capacitors in the circuit. I don't have very many components on hand so I had to steal the capacitors from the voltage regulator for now, and just used the resistors I had to hand, but the frequencies come out in the audible range and different resistors do indeed create different tones.

Yes, this is a pretty boring outcome so far, but it's amazing how much I am re-learning just in the process of getting all the gear together and setting it up! My Arduino board should be arriving soon, and I have the Processing language installed and I am playing with it so that I can make my computer talk to the microprocessor, all on the way to a fun application I'll write about as I get further along.

Week 8: How twitter might change news

Well, I'm not exactly keeping up a weekly project every week but I thought I might as well number sequentially and in some weird dream land I might catch up to the actual week number... but anyway...

This week, the creation is another essay. It might seem like cheating a little but I think that writing this particular analysis was creative in its own way. I absorbed myself in a process and learned a lot and then created by distilling it.

Essentially I watched a news story break over twitter, and then inspired by a comment about the fast news cycle, started to think about the implications for how people will react to conventional fast-breaking news stories in the future. I asked a question about it, which provoked some discussion, and that led to me fleshing out my thoughts in this essay.

The essay is over on Cathemeral Thinking but this is how it starts:

On Thursday morning (US Pacific Time), March 12, 2009, a piece of debris came close enough the International Space Station to require the astronauts to take refuge in the Soyez module, just in case there was a collision. In the end, the debris passed by without incident.

I experienced this event almost entirely through twitter. This essay is to share my experience about how this is an example of ways in which somebody can follow news in a format completely different from conventional news reporting. This experience is, obviously, peculiar to me, in that only I follow my set of twitter users, and this is my personal reaction to it. However, I believe that this kind of process is starting to occur for many more people and it changes the way those people will use conventional news reporting.

For the rest, jump over here.