Month: November 2007

More Arduino Fun

So I took the blinking light demo provided with the Arduino platform and expanded upon it. In fact it’s still being expanded upon.

My first creation is a Morse Code Sender that flashes out my amateur radio callsign.

Next up I have to find out what happens to the digital pins when they’re set to low. If they ground out it’s perfect since I can use low state pins on the cathodes of the 8×8 matrix, and since an LED is a diode, it’ll block current flow when the pin is in a high state, if my theory is correct. I’ll be testing that out later on.

News beyond the sound bite

I’ve stumbled across something I’d very much like to see succeed. It’s called the Real News Network.

This story out of Australia is downright scary, particularly since we’re now seeing issues in Atlanta, GA and it’s a well known secret in the northeast that we’ve been under drought conditions for the past few years. It just hasn’t caught up to us yet, but it will

I want to see the global warming nay sayers watch this video and tell me with a straight face that global warming is junk science. I want to see them clamoring for fresh water, cursing the entire time because they believed an industry shill.

Providence Geeks 11/21/2007

Providence Geeks holds monthly get togethers to discuss various technology subjects. This months had Paul Badger from RISD talking about his Bare Bones Board which is basically an Arduino but due to name issues he had to come up with a new name, hence the Bare Bones Board (BBB). He was going to charge us $15 for the board but instead charged us $10 and Brian Jepson charged us $5 for the breadboard and hookup wire kit.

I had a really good time there this evening. Got my board mostly soldered up but didn’t put the header pins all on. I did manage to flip the header that connects to the solderless breadboard to the wrong side but I found that’s easily rectified. Just heat the pin for about 3 seconds and push through with a pair of pliers and then let the remelted solder do the job.

I have plans for these Arduino’s. One is for an encrypted door lock over an RF data link. Think key fob except mine will be about the size of a deck of cards, maybe a bit smaller. It is similar to those used for cars except a lot more secure and it opens the deadbolt on your house instead.

The other thing I want to build which doesn’t require any computing horsepower is an RF doorbell but not how you’d think. I frequently have the earphones plugged into my head (The Philips SHN2500’s are pretty sweet, they do have drawbacks though the price is right!) and I will not hear the doorbell when that happens. So I’ll hook one RF unit into the doorbell and the other will have a flasher on it, and maybe some sound device.

And happy of happies, those of us who bought the BBB at the event were entered to win a book. It’s by Tom Igoe and called “MAKE:Projects – Making Things Talk”. And thanks for letting us know you edited the book Brian. Anyhow I was the lucky winner and there’s a whole section on RF that complements my book collection on RF design. And I looked at the Make Store and noted the book wasn’t even available there yet. So there are some definite benefits to attending.

I also met several interesting folks this evening and look forward to seeing them again. In particular I’m very interested in DC401 or DefCon 401. Only problem is that right now even $50 a month is a swing though I’d dearly like to see them find a space and have a nice hacker space for the Providence area.

What I’m clearly getting at here is that I’m glad we’ve reached critical mass in the area for electronics hobbyists. There were a few people there this evening who had never touched a soldering iron before yet were soldering together what I’d consider to be an intermediate level kit. I had fun showing one of the others at the table how to open up a soldered in hole on a printed circuit board.

And for any who may visit my blog here are the electronics and robotics stores in Providence that I know about:

1) A&J Supply/Distributors
Location: 9 Parade St, Providence, RI 02909
Phone: 401-421-0991
Note: Great staff, prices are pretty good too.

2) Wm. Dandreta Co.
Location: 28 Wolcott St, Providence, RI 02908
Phone: 401-NXX-XXXX
Note: Unfortunately Dandreta Co. went out of business a bit less than a year ago.

3) Old Fashioned Robotics
Location: 14 Cedar St, Providence, RI 02903
Phone: 401-276-4216

Now playing: The Gap Band – You Dropped A Bomb On Me
via FoxyTunes

Currently reading

I picked up two new books at the library. If you live within a few miles of one, a public library is a fantastic resource. Mine is the Providence Public Library, a bit of an oddity since it’s not owned by the City of Providence, but is owned by a private foundation.

One is titled “Same Time, Same Station: Creating American Television 1948-1961” by James L. Buaghman. It’s a very interesting story about the the two potential directions that television could have gone in during the early days. At the very beginning of the book the author tells us about the movie studios refusal to help produce television programming and how the movie industry was tanking back then. And it’s tanking again now.

In addition, there was a huge battle against RCA/NBC under the leadership of Sarnoff by the Columbia Broadcasting System. Columbia actually had a color UHF television system setup and ready to roll in 1946 but the FCC denied them the chance to move forward.

Television was a disruptive technology, same as the Internet has been a disruptive technology for the past decade or more as it reached general acceptance. When I think about it I remember my first connection to the net was via a SLIP (Serial Line Interface Protocol) connection. All there was a the time was email, ftp, gopher, IRC (Chat) and NNTP (News). Now we have all those though gopher has been replace with things like Google but we’ve added a few tricks. VoIP has made a very big splash and has the incumbent carriers VERY scared, and the web has exploded with new things like social networking, video, audio, and most interestingly P2P file sharing.

And of course the movie studios don’t like P2P because they never saw the benefit that it could provide them. There was a good article on the Huffington Post this morning that lamented the fact that there are no tech savvy people in the entertainment industry.

The other book I’m reading is “Learning C# 2005” by Jesse Liberty and Brian MacDonald. Considering that Stanford wrote the applications for their autonomous car that participated in the DARPA Urban Challenge in C# and Microsoft uses it fairly exclusively to write the Windows operating system I figure it’d be a good language to add to my collection. Stanford did come in 2nd.

One of the touted benefits of C# 2005 was supposed to be automatic memory management. And for the most part that’s true. But the Stanford team found out that it still has what are called memory leaks.

A memory leak happens when a program or application requests memory resources but when it’s finished with them they’re never released yet the memory manager may flag that section of memory as being available. Then you’ll have a mixture of two different types of data which does very bad things to interpreters and compilers.

If this got a bit too geeky, fear not. If you’re using a Windows computer with at least Windows XP on it, you’re using a product written with C# (C-Sharp)

So now I’ve had exposure to C, C++, and C#. So many variants based upon the C programming language originated by Bell Labs.

Am I ever exhausted

So I’m doing contracting work and todays project was wiring up a couple cable outlets and network outlets in a house. I scoped the project earlier and though, eh, two hours ought to do it.

How wrong I was. First of all the way the house is built is a split level. I’ll never again wire a split level. You want me to wire make it a one floor with basement, or even two floor. If it’s two floor know that we’re going to have to tear a channel into the wall to route the wiring. To top it off the room sat over the garage and the garage had finished ceilings. This necessitated running everything along the sill. Fun, fun, fun.

Maybe I was a bit to hasty about split levels. If I ever run across one again I’ll just use a reciprocating saw to remove a small section of wall/ceiling in order to more easily run cable. Fishing it through tiny little holes is a major pain in the ass. I’m being quite literal when I say that since I’m one hurting guy right now.

While doing the last room I ran into a problem. I had pulled up the Cat5e and then tried going back for the coaxial cable. I dropped the fish back down again to retrieve the coax cable but something happened. When I tried to pull the fish tape out it snagged on something. I was reluctant to pull much further since I probably snagged an electric line so I cut the tape off and tucked it under the floor and then did the next best thing, I tied the coax to the Cat5e and pulled it through only to find that a 7/16″ hole wasn’t big enough. Took about 45 minutes to dig it out and finally got the coax through though the terminating end was destroyed. Of course after that I realized I could have gotten cable pulling grease but that would have been too easy.

After that I terminated all the ends for the Cat5e and cable into nice pretty little jacks. This is one of them. Combination network and cable TV jacks with plate

Terminating the jacks took the least amount of time. For the coax F connectors you just make about a radial slice into the outside jacket about 5/8″ down. Then you slide the outer insulator jacket off and you’re left with a layer of braided shield which has to be combed out and trimmed. Then you have to cut through the second layer of shield and through the dielectric to get to the center conductor., including opening up the coax, combing out the first layer of shield and then cutting down the second layer and dielectric too. That leaves you about 1/4″ dielectric and second shield, and 3/8″ of copper center conductor. Slide it into the F connector and then crimp.

Total process takes less than a five minutes per connector assuming you have a crimping tool. Thankfully I do have one since otherwise it’d be the pliers.

The Cat5e is also easy to terminate. I wire them using the T-568B standard. Just lay the wires into the channels and use the punch down tool to secure, keeping total length from last twist down below 1/2″

That’s about the same difficulty level as doing the coax. When all was said and done and the patch cables hooked up to routers, computers, TV’s etc. everything worked on the first shot. Got to love when that happens but I was confident that it would. Even sized the cable correctly as I actually had about 20 feet of extra for each to play with.