Ones and Zeros

In a hospital waiting room I saw two signs.  One announcing the availability of free WiFi.  The second telling people to turn off their cell phones for safety.  WiFi frequencies are around 2.4GHz, cell phone frequencies are 850 MHz, 1.9 GHz, and 1.7 GHz, and 2.1 GHz.  In other words, not that different.  Power levels are similar too.

So, what gives?  My theory is that cell phones are banned not because of equipment interference, but becuase they don’t want people bugged by one side of 15 minute-long conversation about someone else’s inane office politics.  Kinda like the one I had to listen to.

Or, it could be just technical ignorance.  Anyone know one way or the other?

I got this idea Friday.  I would do a Cylon pumpkin with the red LED eye-scanner moving back and forth.  A quick google search and I found that others had done the same thing.  I even found code for the Arduino board to do this.  (Ok, I’ll tweak the time constants, I thought his was scanning too fast.  It looked like an anxious cylon to me.)

My wife had bought some great pumpkins so all I needed was ten bright red LEDs.  I have ten LEDs already, but of miscellaneous colors and brightnesses.  Off to Radio Shack, or “Shack” as they oddly call themselves now after a basket-ball player.

Of course, Radio Shack doesn’t have them.  And what they do have is poorly organized, the bin labels don’t match the contents. The sales guy took pity on me and called their other stores.  No one had them.  Some don’t even carry parts anymore.  There are no other stores that might carry stuff like this either.

Radio Shack is moving to selling just cell phones, cameras, and other consumer electronics.  There are a number of other stores that do that better, Best Buy for example.  And there are numerous online sources as well.  Yet, the burgoning “maker” movement of hacking, tinkering, customizing, and creating your own electronics has only online sources for parts and materials in most areas.  Radio Shack is missing a potential market by their rush to what everyone else is doing.

In Silicon Valley, Austin, and other reasonably techy areas, there is Fry’s Electronics.  But here in the Wash, DC area, there’s nothing.  It’s a desert wasteland of unavailability.  This is the way things are in most of the U.S.

Industry and government figures wring their hands sometimes over the lack of engineers and scientists that the US creates.  We import both from India, China, Europe, and Africa.  Fortunately enough want to stay to keep us all in GPS toys and more important things, although that seems to be changing.

The thing is that taking things apart, experimenting, playing with parts, and maybe building something new and tinkering in general is important.  Tinkering leads to design, design leads to engineering, and engineering can lead to scientific inquiry.  But tinkering begins with parts.  No parts, nothing to tinker with.

A lack of easily available parts is directly affecting the next generation’s engineering and scientific abilities.

When we moved into our current house (quite some years ago now) I decided that I didn’t want to run cat-5 wiring yet again. A few trials backed up that opinion. We decided to try this then new-fangled “WiFi” thing. I’d been using it at work and other places.

When I put our WiFi router in we had the only one within reception distance.

Now, of course, I think there’s one per house. Ok, that’s exaggerating. But it’s not uncommon to see 4 or 5 on my WiFi scanner at the same time. Most are only turned on for a while. I don’t understand this, ours is on all the time. After all, if you’re going to look something up on Wikipedia, check on an actor in IMDB while watching a movie on TV, check tomorrow’s weather during a commercial, or verify the lyrics to a song, you need a laptop that’s just sleeping, and an active WiFi connection. (All those examples are from last night.)

But, I’m not disappointed that my neighbors turn off their WiFi sometimes. It reduces the interference for us.

WiFi routers have an “auto channel select” which picks an unused channel out of the 11 or 15 channels (depending on what standard protocol set your router and computer know). This sorta works. Near my WiFi router there’s no substantial interference from the neighbors so my router defaults to channel one. But sitting with my laptop out on the deck, my laptop does see interference.

Unfortunately, most of the other WiFi routers my neighbors have also end up defaulting to channel one for the same reason. The result is WiFi congestion, low bandwidth, and even an occasional dropped connection. It makes me long for the days of pulling cables in the crawl space.

So hence my WiFi experiment. There are three non-overlapping channels for WiFi: 1, 6, and 11. The others overlap to some extent and the overlap degrades the bandwidth a little through the spread-spectrum link protocols. But having two or three of us all using the same channel stresses the spread-spectrum capabilities too far apparently.

I’ve now set my WiFi router to use channel 6, which isn’t widely used in my neighborhood. It’s still too weak on the deck to easily establish a connection for my older MacBook Pro laptop. (However, my wife’s newer laptop and our iPhones make connections easily there.) But the real test is maintaining a connection.

So far it’s working nicely. I’m just hoping our neighbors don’t catch on and change their channels too.

(Note: I’m using the term “WiFi router” pretty loosely here and just got uncomfortable with that.  Ignore this if you’re already familiar with networking equipment.  A “WiFi router” is a combination of a WiFi point-of-presence, a router (or more accurately in my case a hub), and a firewall. All three software devices are contained in one hardware device. This device is basically a specialized computer dedicated to these software programs. We see it as one thing since there’s one physical thing to see.)

I’m not a security guy, that’s a whole ‘nother software specialty. But I write software, and have a fair amount of experience with networking software. That makes me aware of security issues. But I don’t need much doesn’t require much security experience at all to anticipate this kind of thing:

LAS VEGAS — It’s one of the most hostile hacker environments in the country –- the DefCon hacker conference held every summer in Las Vegas.

But despite the fact that attendees know they should take precautions to protect their data, federal agents at the conference got a scare on Friday when they were told they might have been caught in the sights of an RFID reader.

The reader, connected to a web camera, sniffed data from RFID-enabled ID cards and other documents carried by attendees in pockets and backpacks as they passed a table where the equipment was stationed in full view. (See the full article here.)

I’m just a software/networking guy. And I know better than to carry an RFID-enabled card to DefCon. I know that RFID cards can be read remotely. And I have my concerns about RFID passports and other critical ID. So, you’d think that Federal personnel who ARE security geeks would know about this and realize the implications! After all, DefCon is a key conference for security people, you’re not there if you’re not interested in technical and computer security.

I’m also writing this here so that you’ll know - even if you’re not a geek at all - that more and more ID cards, credit cards, toll booth payment devices, and similar items have RFIDs. If you can wave it near something and have your card work, it’s an RFID. And it can be read by someone you don’t want to read it. Sometimes something that’s more convenient for you is more convenient for a thief too.

There are protections like passport wallets and the like. Or, you can decide when and where you want to carry it basing that on any potential effects of theft and the potential risk of that theft. But don’t be like the Feds at DefCon who were surprised with the obvious.