Internet Exploder

I just noticed my blog looks awful in IE7 and even worse in IE8. Are there any html gurus in the readership that would be kind enough to tell me whats wrong?

Update: I switched to the “classic” theme and then back to the theme I like and the site is now rendering properly in IE7. There appear to be a few icon images missing, I’ll have to dig those up from somewhere.

Austin Trip

My train tickets are confirmed and on their way. Finding a ride and a room in the area are proving to be more of a challenge then getting the transport. Amtrak is fairly simple compared to the airlines – there is only one train that goes there and it only has one schedule; take it or leave it!

From my research, the trains are on their schedule down to the minute – so when Amtrak says I arrive at 7pm, that’s when the train pulls into the station. I don’t know how long it’ll take to unload, or to claim my baggage. Right now I’m thinking I’ll take a rolling suitcase of mostly clothing, and a duffel bag with a few clothes for the train ride and most of my electronic gear. The duffel will stay with me in the roomette and the roller can get checked into the cargo area. I’m impressed at the luggage “restrictions” that Amtrak imposes – each passenger is limited to 5 bags, weighing not more than 50 pounds each. You get two carry-on bags and three pieces of checked luggage. Each piece of checked luggage is limited to 36 by 36 by 36 inches, which I think is a total of nine cubic feet, and I could take three of those! Of course the 50 pound limit kinda gets you there – any kind of crate that big would probably weight more than that.

The best deal on a rental car I’ve found is using a discount code from Amtrak with Hertz. However, the logistics of securing the ride are proving difficult. The auto rental places are all at the airport and the train station is on the other side of town. From what I can see on google, the station is very small – just a little building, a single rail platform and a small parking lot. I think I’ll end up with a cab ride to my motel for the first night, and then a cab or shuttle to the airport the next day.

I’m still on the hunt for rooms; downtown Austin is out of my ballpark, with most rooms costing $150+. I got a laugh that O’Rielly has a deal the the Austin Raddison for $147 a night using the coupon code MAKER – I guess working for a small time tech publication has its perks! The best prices seem to be in the North end of town, and the suburb Round Rock. There is a large shopping mall called the Arboretum that has a mix of high end and low end hotels around it.

Even though it’s more than a month away, I feel the need to start making a list of the things I want to take along.

Maker Faire: Austin

I really enjoy reading the Make website – it’s a great collection of all the DIY stuff that’s going on out there. And all the different events they cover look like fun. So I’m going to the Maker Faire in Austin this fall. I believe the dates are October 18th and 19th. Is anyone else going, are any of my readers from the Austin area? Shoot me a gmail @ gordonthree if you know anything about any of this! I don’t know anything about the Austin area, and the various online mapping tools aren’t offering up a lot of detail either.

The last vacation I took was way back in 2005. I made a road-trip to Florida, to watch the space shuttle’s return to service flight after the Columbia disaster. I got there, hung out with some family for a few days, no space shuttle. So I went down to the keys for a few days, shuttle still was on standby. Spent nearly two weeks, and didn’t achieve much but a decent credit card bill. The drive through the mountains was fun… The road leading from south-eastern Tennessee through North Carolina was really something – winding roads with a sheer mountain face on one side, and a sheer drop off on the other. Mix that with lots and lots of big trucks going way too fast, just enough rain to make the road greasy and twilight from a just-setting sun and you get “white knuckles” kind of fun! On the way back I got to see Corvettes being built and climbed around in the Mammoth Caves system for a few hours.

I bought a new truck this year in June – it is a gas guzzler but the price was unbeatable and with huge tires and four-wheel drive, it’ll be fun in the Northern Michigan snow. However, trying to take a road-trip vacation anywhere with it would get real expensive real fast – 18-20 mpg on the highway at $4/gallon – oh yea! That leaves mass-transit; Originally I was looking at flying from Grand Rapids – the airfare was reasonable and there it was a fairly direct flight with only one lay-over. While I was pondering my options, the price almost tripled. Lower oil prices equal higher airline fares I guess. I could drive to Detroit and fly from there, but that’ll cost a lot of gas money and parking at Metro is not cheap.

My folks suggested I look at taking the train. Originally, I had dismissed the train since it takes thirty hours to cover the roughly 1200 miles. However, after the spike in fares, and reading about the TSA’s crackdown on IEDs, I figured flying might not be the best option, especially if I wanted to take some of my projects along for show-n-tell with other makers should the opportunity arise. With the cost of a sleeperette added in, the rail cost half the cost of first class, but a few hundred more than coach. If I wanted to ride coach, it would be real cheap, but I have reservations about sleeping in “public”, which might occur sometime during the ride. Traveling “first class”, aka, private room / sleeperette, Amtrak is apparently very accommodating. They include a bunch of meals, free pop/water and a generous luggage allowace. The room apparently has 120v outlets for gadgetry, so I don’t need a suitcase of batteries to run a laptop on the journey. To make things more interesting, I’ll be taking a commuter train from Holland to Chicago. To get to Holland on time, I’m looking at a 0530 lauch time. So 30 hours on the long haul train, 3 hrs on a commuter train, 3 hr layover in Chicago between trains and a 2 hour drive to Holland equals roughly 38 hours? That’s a long day!

Anyway – I wanted to write a bit about this so I can get it out of my head – and see if anyone reading the blog knows about the area or show, or is planning on attending? My thoughts are rambling now so I’ll have to recompose things and write some more later.

LED Cube

I was trying come up with something impressive to write about, after having the blog dormant since July. I tossed around a lot of different ideas… Although I haven’t been writing, I’ve been dabbling in a number of different projects. None of them are really in a state I’m ready to write about. That brings me to something I saw a few months ago on MAKE:. Bre and associates had constructed a simple 3x3x3 led cube, re-purposing a POV toy to drive the leds.

I figured this would be a good easy project I could finish in a day, so I drilled out a piece of pine board and set to soldering up some 3mm leds. I wasn’t very careful, so the little matrices look kind of ugly, but it all works and you can’t see the wires in the dark!

3x3 led matrix building

It didn’t take very long to toss three of these nine led matrices together. Assembling them into a twenty-seven led cube was a bit trickier. I used some gator clips to hold parts of the cube while I soldered it. Eventually I finished all the connections and had a passable cube with fairly even spacing.

3x3x3 led cube finished

Assembling the matrix is a pretty straight forward task. All you really do is tie all the cathodes together. Each matrix will become one row in the finished cube. Electrically, the cube is built as a 3×9 array, three rows and nine columns. You could probably build it the other way around, anode rows and cathode columns, but it is easier to sink a large current than source it. I think the MAKE: software only lights one led at a time, since they’re relying on the microcontroller to both source and sink current. My design is a bit different. The mcu sources current to each anode column, and N channel fets sink current for the entire row. The N channel is easily able to sink a few amps, so the cube can light an entire row at once without having to multiplex the individual leds.

In order to keep the PCB layout simple, the connections are spread all over the place in terms of the registers inside the pic. It would have been cleaner to organize eight of the nine columns as a single 8bit register on the pic, leaving only one bit left over to deal with. Instead, I’ve created symbols for each column, and set them individually from 9bit numbers.

Each anode column is current limited by a 75 ohm resistor. The value chosen was rather arbitrary, since the leds have such a low duty cycle, a lower value would have afforded me more brightness when the cube is battery powered. I can tweak the brightness a bit in the software, changing the scan rate the rows are multiplexed at.

That’s pretty much it. I’ve found there’s not a lot you can do with only 3x3x3 and 1 color, but it’s still kind of fun. Trying to think in three dimensions while drawing the animation frames is kind of tricky. I started with excel, but that wasn’t very useful – I spent more time copy and pasting formulas than I did ‘drawing’. Luckily my buddy Dan helped me out with that. He whipped up an awesome little php script that lets you draw animations 27 leds at a time, and it formats the resulting numbers so I can copy and paste them right into the code.

There’s a few videos of the cube doing various things on my Youtube Channel. Here is perhaps the most interesting one so far.

Thanks for reading, and Happy New Year!

Dry reading

The next few months might bring some dry reading for the visitors to my blog. The camera I do 99% of my photographic work with has died silently sometime this past week. It’s not that the camera is dead, but it might as well be, as it appears the imaging chip has failed, or the circuitry that processes the signal from the chip.

Here’s a shot of the sprinkler controller I’ve been working on.

That picture was taken in a sun lit room, with overhead lights and a work lamp on. Plus the camera’s AI fired the flash at full power.

I’ll be contacting Nikon regarding repair, but unfortunately, I’m pretty sure it’s the end of the line for this cam. With 3rd quarter taxes coming shortly, I’m not in a position to make a big purchase right now, so it might be a few months before I get a new cam.

If I get desperate enough, you might see some awful pictures from my cellphone on here!

Addendum:

The camera in question is a Nikon Coolpix 5700, which is listed as one of the models affected by the Sony ccd failure problem

Update:

Although my problem doesn’t fit the description of the current “service advisory”, Nikon is going to check it out. At best they’ll repair it for free, at worst, they’ll give me a quote on repairs. If it’s within the price range of a new ‘throwaway’ digital, I’ll get it fixed. Otherwise I might just grab an HP / Epson / “insert brand-x here” throwaway to get me by until I can buy something nicer.

Capacitive Sensing Continued

Hello readers from MAKE: as well as all other readers 🙂

My prototype touch sensor worked so well, that it hasn’t needed much changing. I sent the design off to Custom PCB, and less than a week later, I had a pile of circuit boards waiting for me.

I changed the layout around a little, mostly adding a 2×8 header for accepting a ribbon cable style connection. The header combines power, ground and outputs into a single connection, making it easier to connect to the main board of my larger project (sprinkler controller). Each touch output is paired with a ground wire, which I suppose makes it more resistant to interference. The caps I used this time are polyester film 220 nF, doubling the amount of capacitance compared to what was used on the prototype.

Yes, the ugly piece of plexi is still ugly. Don’t worry, it will be hidden from view. In the final configuration, this board and its plexiglas spacer will be inside a plastic project box. I’ll have a laminated “keypad” overlay affixed to the outside of the box so I can see where the buttons are. The spacer will be flipped around, going on the solder side, giving me enough clearance to flush-mount the sensor with the wall of the box. Flush mount is very important, as even the slightest air-gap will ruin the proximity sensing effect.

Nothing much to see solder side… a few smt passives set options on the chip, as well as decouple and filter the incoming power. The big resistor limits current for the meager power led which no one will ever see once the board is in use.

I’m very close to finishing the larger irrigation control project, hopefully sometime this week! Thanks for reading!

Capacitive touch sensing

Presenting “6buttons”; a simple six button keypad based on the QProx QT160 charge transfer proximity sensor chip.

More details to come later, wanted to get some pictures and video online tonight.

simple schematic – i plan a “backpack” pcb which will provide some visual feedback, a clicking noise and translate the six outputs into an i2c bus device.

the brains of the operation, this chip does all the work. special mylar capacitors are required for it to work properly. i tried cheap-o ceramics with terrible results. the orange thing is a 10mhz resonator.

the “buttons” are printed out on plain paper, using the silkscreen layer from my pcb layout program. the capacitive dielectric is provided by the FR4 pcb material, the paper and a 1/8th inch thick layer of plexiglas; I guess you call that a multilayer capacitor!

the sensors are simple copper rings, which radiate the electrostatic field this chip uses to sense proximity. a ground plane pour around the IC helps to minimize cross-talk between sensor channels and prevent stray fields from detecting proximity around the chip itself. the capacitors near the chip also sense proximity and will need to be shielded with aluminum foil or something.

forgive the craptastic music in the video!

edit: also read Capacitive Sensing Continued

Random picture

I found this digging around some old forgotten directories on my web server.  It appears to be four dimly lit RGB leds.

5mm rgb led

LED Clock; Firmware taking shape

The firmware for my LED Sign / Clock project is taking shape.  I’ve worked out my initial wishlist of features, and put together a basic menu structure.  I figured a menu is the  easiest way to access a lot of options, while only relying on two buttons.

The basic menu consists of options for setting the time and date; minute, hour, day, date, month, year.   The basic options are pretty self explanatory.  I have also planned some more advanced options:

1. Adjustable display brightness – Varying the duty cycle and refresh rate of the matrix can effect its brightness.  I need to make a simple scale for these variances to allow for two or three brightness levels.

2. Adjustable scrolling speed – The program draws the same information several hundred times per ‘scroll’, changing this counter affects how fast the display appears to scroll.

3. Selectable time format – User can choose between 12 hour AM/PM time and 24 hours ‘Military’ formats

4. Message Mode – User can enable / disable scrolling messages as well as display a single message, a random message or messages in sequence.

Other than that, the code is still pretty basic.  I’ve completed a bunch of internal fixes, like the scrolling code now handles messages of variable lengths. up to sixteen characters.  I’ve also created i2c eeprom reading routines to extract menu prompts and other text strings I’ve stored in the eeprom to save flash space on the chip.

Migration to new host, success?

I’ve moved the blog to a new host. The old host wasn’t really that bad but they did seem to get ‘slow’ at times, and there were problems with their logging and apache stats.

Right now the Counterize plugin for wp is offline, pending me bringing its massive 40 mb table over from the old host. I don’t think my readers need Counterize for anything, so it shouldn’t be much of an effect on the general reading of the website.

If anyone notices anything else out of place, please drop me an e-mail. My address is gordonthree at gmail dot com.