What’re you doing Sunday evening? Nothing? Come down to NYC Resistor where starting this weekend we’ll be working through the Introduction to Algorithms course available through MIT’s OpenCourseWare project. What’s OpenCourseWare?

MIT OpenCourseWare (OCW) is a web-based publication of virtually all MIT course content. OCW is open and available to the world and is a permanent MIT activity.

We’ll start at 5pm and the lectures run about an hour and a half. The time may shift a bit each week due to other classes happening at the space, but we’ll post it on the calendar well in advance. The class uses the text “Introduction to Algorithms” which you may want to pick up or borrow from a friend. We’ll try to scrounge up a couple copies to have on hand.

This event series is totally free to attend, but if you enjoy it please consider donating to the MIT OpenCourseWare project!

This week we’ll be watching Session 1: Introduction – Analysis of Algorithms, Insertion Sort, Mergesort

 As part of my knucklebuster hacking project, I’ve been working with a portable thermal receipt printer. I picked up a Citizen PD-22 on eBay at a very attractive price, but later realized why it was so attractive: the printer uses a proprietary RS232 cable, and replacements are hard to come by at any price, much less a reasonable one.

Aside from that hitch, the printer itself is great. I found a full list of the control codes on the manufacturer’s website, and got it to spit out some configuration information. It runs on 4 AA batteries, which fits the bill of "portable electricity" for our show. 

The printer also has an IrDA port, but after poking at it for a day and talking to a friend about it, I’m abandoning hopes of getting the Arduino to interface with it. I have a bunch of IR LEDs, but the IrDA protocol is apparently a big pain.

Poking around on DigiKey didn’t bring up any connectors which fit the bill, so at the suggestion of someone on the NYCR Microcontroller Study Group list I set about building my own by etching a tiny PCB with appropriately spaced traces.

A pair of calipers measured the traces at 0.8mm, so I came up with a board in Eagle, shown at left. It’s super simple, just 10 wires and 10 holes. I plan on using a Makerbot to make a nice little housing for the board, after I trim it down some. 

Note that the traces fan out at the end simply because I am not very good at soldering in small spaces, and i wanted plenty of room for error since I was using the toner transfer method of making the PCB. 

The board was actually a bit too thick, and while someone more patient might have ordered thinner copper-clad board, I am nothing if not impatient so I took it to the belt sander to remove a little bit of material from the back.

 After some trimming I got something which appears to work! I’ve located power and ground on the pins, but not much else. None of the other pins seem to be saying anything, which is surprising.

Still left to do is drilling out the holes for the wires and soldering them up. Then I’ll cut/file the excess board away and build a little housing for it on a Makerbot. I may decide to re-etch the board with slightly longer traces, right now there’s *just* enough room to clear the printer housing. That and one of the traces didn’t come out quite right (although it’s still serviceable as-is).

Admittedly, I did end up ordering an official cable for the princely sum of $35. I figure I can use it as a control, and to double check that I’ve figured out the pins. So far I haven’t located TX/RX. I would have expected RX to be floating, but my cheap RadioShack multimeter shows no signs of life on the other pins.

I always wanted a cute little herb garden. There are two problems: I live in an apartment with no yard, and I have a black thumb. I generally forget about my houseplants, and then they die.

Which is why I’m excited that my attempt at building an aeroponic garden for growing basil, oregano, etc has been successful so far:

I set up two different pots, one using an air pump and airstone, the other using a water pump and some tubing/sprayers. The results have been mixed, and I’m still revising things. But now I have some basil that’s just about ready for me to steal some of. The nice thing about this setup is that it’s totally automatic. I can forget about it for a week and that’s just fine. All I have to do is top off the water once a week or so.

A full report, including an explanation of how the two setups were built can be found here: http://www.kellbot.com/category/projects/diy-aeroponics/

There are still a few spots left in this weekend’s PHP Classes, so if you’ve always wanted to learn PHP here’s your chance!

Beginning PHP runs from 1pm to 3pm on Saturday and covers basic PHP syntax, functions, etc. It’s perfect for people with little to no previous programing experience.

Object Oriented PHP is a class for folks who already know their way around PHP and want to learn object oriented programming to go with it. We’ll cover the basics of OOP, and some of PHP’s OO excentricities. It runs from 1pm to 3pm on Sunday.

Snag your spot now before they fill up!

Our first swap night was a success! There were lots of goodies being traded: mysterious old EPROMs, old iPods, a steam engine, a laser barcode scanner, resistors by the reel, even a Wii. Most folks left with a little more than they came in with… but at least it was different stuff!

If you didn’t make it you missed out an a lot of cool stuff, but don’t worry; We’ll likely have another one in the future!