A Big Magnet

Squigaloo kickstarter

2011-06-17T11:15:00.000-07:00

I generally don't post work related stuff here, but this is just too big for me not too!
For the last year or so my business partner Andy Lueck and I have been hard at work on Squigaloo, our collaborative storytelling startup.

Just this morning we launched our kickstarter campaign to raise some money so we can finish it off! I would love it if you take a minute to look at what we are doing, and (of course) to make a pledge!

Maybe if this works I will have a little more time for projects here :-)

Thanks!

Josh

Making progress on fixing the south bend lathe again

2011-05-21T11:22:00.001-07:00

Using some nice one part industrial enamel. It stinks but it goes on well with a brush and dries to a hard glossy finish. I am putting on two coats over a phosphate based primer, and although I see all the inconsistencies in the casting I have so far resisted the urge to break out the bondo. So far.

I am averaging about two parts a day, but the weather has just gone back to cold rainy, so I am going to fall behind.
The bed sitting to the right is going to be tough to clean well enough to paint, if only because it is so heavy that it is hard to manipulate.

The color is WAY off. It is really a nice dark blueish gray (instead of robins egg blue).

I have started YET ANOTHER BLOG just for this project

SlowLight in Winter Lights show at Vermillion gallery

2010-01-16T19:45:00.000-08:00

One of the best parts about being involved with Dorkbot is that it has kicked me into making some new sculptures. The Winter Lights show at Vermillion Gallery opened last Thursday and our piece was in it. Bob Gallup and I collaborated again with great results I built the physical platform and Bob handled the software (with his usual skill and aplomb). The piece uses a UV LED to draw vector patterns on a phosphorescent screen. It is controlled by an Arduino, with an Adafruit motor controller board to run the motors.

I am really happy with the way it turned out. The flotsam piece we worked on last summer was a bit of a compromise for me. I had not yet gotten the garage set up, and many of my tools and materials were still packed away. This time I had most everything out and ready to use. I treated this as an exercise in patience and intention. Every step was carefully considered, and if I screwed something up (which was often) I did it over again instead of hacking it together. I wanted to try and build something that looked as if it would have been right at home in an early laboratory, so that meant it had to look handmade, but also polished and "engineered". Every decision was made based upon functionality, and I tried very hard to avoid any kind of ornament or decoration. Although I would really have appreciated the milling machine I left in Philadelphia, I was pleasantly surprised with how much I could do just using my drill press, band saw, and hand tools.

I started by building a frame from scraps of reclaimed Douglas fir from a local architectural salvage place. I have completely fallen in love with stuff. It is everywhere out here, and I really enjoy working with it.

The next step was to start laying out bit and pieces of ink jet and scanner hardware. I was looking for a good pair of stepper motors that I could use as X and Y axis drivers. I have lots of these so it was not too hard to find two that would work together, I also dug out a pile of polished steel rods (also from printers and scanners) and some linear bearings that originally held the print heads of an ink jet.

The x-axis is almost a complete steal from an old scanner with the ink jet linear slide being the only addition. I made up a brass plate to ride on the x-axis and hold the y-axis motor and rod assembly. The y-axis is all custom made with bits and pieces from aho knows how many other machines. It was fun to machine up the various fittings I needed for keeping everything in place (even though I ended making many of them at least twice).

Brass was my material of choice as it is easy to work, and it looks great with the warm color of the Fir. I was initially very concerned with how to manage the wires. I considered lacing them, but in the end I made long brass springs out of fine wire and slid the wires through them. They look amazing (if I do say so).

All of the materials, and most of the screws and fasteners are from other things I have taken apart or collected. I think that at most I spent $30 for materials, much of it on the phosphorescent paint. A few coats of shellac gives the fir a perfect "old school" finish, and adds to the antique feel. Once done I turned it over to Bob to write the code. He managed to build quite a sophisticated system in just a few days. I will let him describe it (hopefully) but I know he took his inspiration from the old logo turtle graphics and built a parser that can read simple "programs" to draw the patterns. Here is a video he took at the opening, and if you are impatient skip ahead to about 1:11 to see it start drawing one of the 6-7 patterns it draws at random. Bob refers to this one as "triangle 90", but I call it "Iron cross". Bear in mind, it is called SlowLight for a reason...

Arduino PID library in the playground

2009-11-13T15:51:00.000-08:00

I just found out that user br3ttb created a very useful looking PID library for the Arduino.

I had considered turning my hacked together code into a library, but never got to the point where I thought I could pull it off.

This should definitely make it easier to test various physical setups as it will standardize the software to a great extent. I can't wait to try it out with a real project. I even have one!

next show

2009-11-10T09:18:00.000-08:00

Last summer I worked with Bob Gallup on a piece for the Dorkbot Seattle show People Doing Strange Things With Electricity IV. We built a driftwood and steel sculpture inspired by sea urchins called Flotsam. Coming in January is a Dorkbot related show at a gallery/bar in Capitol Hill, and we are going to try collaborating again. This show has a "winter lights" theme, and we have some cool ideas for a slow scanning image display. The biggest challenge may well turn out to be my unheated garage, but I hope getting started soon will let me avoid the coldest months. The show opens in January and there is lots to do!

Architectural salvage, a cautionary tale.

2009-08-06T08:53:00.000-07:00

We love old stuff around here. Part of it is our interest in reduce/reuse/recycle, but more honestly, we just like old stuff. Something about the history embedded in collected bits of the past makes them feel special. We also love shopping for them at Seattle's trio of great architectural salvage stores:
1. Second Use (South Park)
2. EarthWise (SODO)
3. Restore (Ballard)

We can spend an entire day wandering around and looking at all the treasures they have saved from the dustbin. In fact, for our recent wedding anniversary, that is exactly what we did. Three salvage stores, lunch at Paseo, groceries from the Pike Place Market, and an amazing steak dinner. Perfect!

So when we started planning for our raised bed garden in the little strip next to the garage it was natural to say "lets see what we can get at Second Use" if only because it is right around the corner (almost) and we don't need much of an excuse to go there. We found that they had a huge assortment of glazed terracotta facade tiles from an old apartment building. These had been around for awhile, and had slowly been coming down in price until they were $2.00 each. They were just what we were looking for and, at that price, were cheaper then anything new. It took about 4 trips (in the CRV) to load and move the 40 or so tiles we needed, but as soon as we got them home Rae got to work cleaning and moving them into place.

She spent most of two days working on them.
Just when they were all in place, and we were about to start sifting in the dirt, she said "there is nothing we should be worried about in using these, right?".
Oops.
Once asked, it occurred to me that they might have a lead based glaze. A quick trip to the hardware store for a lead test kit and several repeated tests later revealed the sad truth. At least some of the tiles tested strongly for lead. I am still not sure if the results are based upon the glaze (since some did and some didn't). My other theory is that many years of exposure to lead carrying auto exhaust had befouled them. Either way, we were not going to grow tomatoes in them.

Rae was sad, really sad. So I scooted off to the friendly local lumber yard (Alki Lumber, GREAT place!) and bought enough cedar to rebuild the beds. Rae carted all the tiles away, and we quickly screwed together replacements.

Not nearly as pretty, but at least the veggies won't poison us.
The lesson here is obvious, be careful! Oh, yeah, and think ahead.
When I called to let them know about the lead, the good folks at Second Use offered to take back the blocks. We kept them because we really like the way they look. We will eventually figure out what to do with them, but for now they are exiled to the front yard where they line the fence and collect weeds.

We built a patio

2009-06-02T09:32:00.000-07:00

Back in July of 2008 we bought this house and started our renovations. One of the biggest tasks was the kitchen which required a complete gut-to-the-studs redo. That could easily be the subject of another post, or two. Anyway, one of the kitchen issues was a large brick chimney taking up valuable counter space. Whatever its original functions, the chimney was now just acting as a flue for the hot water heater. Not only that but it was crumbly and leaning, looking like a strong breeze might blow it over. Seattle has earthquakes, and it had to go.

So one day during the course of the demolition I climbed up on the roof with our contractor and his two assistants. It only took about an hour or two to bust up the chimney and slide the bricks down into the yard.

It took longer then that to stack them up by the garage!

The kitchen project moved on, but the bricks were too cool to get rid of (not that we get rid of much). They were old, uneven, and covered with mortar but we knew that the bricks would get used for something.

This spring we finally figure out what that something was, a patio for the back yard. The back is small and broken up into several separate spaces. There is a nice sized area outside the basement door, another at right angles between the deck and the garage, and then a large space next to the garage where we want to put a raised bed garden (soon!).

Initially we thought we would just put the patio into the space by the door (about 200 sq. feet). However, as we got started it, seemed to make sense to fill in the shaded and almost useless space between the deck and the garage as well (another 200 sq. feet).

We hunted around online for tutorials and found several that seemed useful. The only problem was that they all looked like they were intended for new construction, flat ground, or simple rectangular spaces (none of which apply to us). The basic concept is simple enough, dig a hole, put in gravel, put in sand, put in bricks. Of course, the devil is in the details. Did we need a weed barrier? Should we slope the hole away from the house? If so by how much, and since we were making an "L" shape that gets complicated! How much gravel? How much sand? So many questions. Our answer was to read them all and then just start digging. We call this the "go go go" method.

We figured on 2" of gravel, 2" of sand and 2" of brick (laid flat) so we dug an approximately 6 inch deep hole. Almost immediately we ran into a problem that goes ENTIRELY unmentioned in all of the tutorials. What the hell do you do with 200 cubic feet of dirt (6" X 400 sq. feet)? We simply piled it up in two big piles and decided we would deal with it later (later has yet to come BTW).

We used some pressure treated wood, and old architectural tiles from salvage for a border. Then we went to the local landscape supply place and ordered gravel and sand. A few days later a truck came and dumped a cubic yard of sand and a yard and a half of gravel which is what they told us would be enough for our hole (and it almost was). The weed barrier seemed like a good idea so we bought landscape "fabric" and rolled it down into the hole before putting in the gravel.

The next challenge was leveling. Our hole was by no means flat, and the gravel was heavy and hard to move. Even with a special purpose gravel/sand rake a friend lent us it was still a pain. After endless discussion about the result we finally just tamped it down with a heavy tamper (also borrowed), and called it good. Then it rained for days (this is Seattle). When the sun finally came back out we jumped at the chance to put in the sand. Heavy. Wet. Sand. Again the leveling was almost impossible until Rae had the bright idea to let the sand dry! Smart that one. We got lucky with the weather and the sand was easy to move once dry, but still hard to level. Eventually we gave up again and agreed it was wabi sabi (this was to become our battle cry).

Finally it was time for the bricks! 1200 or so old, crumbly, covered with mortar bricks. Each of which required hand cleaning to get the big chunks of mortar off. Fortunately, Rae likes mindless and repetitive tasks, so she set about sorting and chiseling and scraping and piling. I started setting the bricks in place and trying to get them to fit without having to cut too many. This is where we started discovering lots of little problems. The bricks were not all the same size so the lines were not straight, wabi sabi! The ground sloped one way and the hole another, leaving an inconsistent depth for the bricks, wabi sabi! The sand was not really level and the bricks ended up in "gentle" lumps and waves, wabi sabi. I realize this all sounds like a mess, and it might have been, except we really ended up liking the random features and the tension between order and accident.

It looks good. Really good! The old bricks have a nice worn look making the patio seem instantly aged and permanent. It has this almost European feel as if people had been walking on it for ages. There is just enough pattern and chaos to be pleasing and it is all ours!

More pictures from Rae

openhackday becomes localhackday

2009-05-29T16:21:00.000-07:00

Yahoo has been running an OpenHackDay in London since 2008.
Oops.
I suppose I should have googled it first, but in my excitement to get things going I just jumped at what seemed like a great name (and it is).
So, I am hereby changing the name of tomorrows event from OpenHAckDay to LocalHackDay.
I like that better anyway!

No matter the name, I hope to see you there tomorrow.

More details here

TGIMBOEJ

2009-05-27T10:10:00.001-07:00

A while back I heard about the TGIMBOEJ project started by Evil Mad Scientists and their friends.
The idea struck me as both ridiculous and extraordinary.
Collect a bunch 'o' junk, stick it in a priority mail flat rate box, and mail it to someone who can take what they want, add what they want to get rid of, and then pass the whole thing along.
I wanted to be on the list of potential recipients but just never got around to it.
Well my chance finally came the other day when I saw a tweet from @EMSL that there was a box looking for a new stopover. I let them know I wanted it and after some quick communication with its last owner I got box Gray-E in the mail yesterday.
I can't say that it changed my life, but there was at least one thing I was excited to get.
Some sample DS1881 digital linear taper potentiometer chips from maxim will be great for an Arduino synth project I have been thinking about.
Of course then I had to put some stuff in the box...
Given the vast quantities of junk I have laying about, I knew the challenge would be one of finding just the right mix of things since I don't yet know where this box is going.
In my humble opinion it leaves here much more interesting then it came in, but that might be my bias showing. The things I put in there were all items I had been saving for something, and they are all useful.
You can see the results for yourself here: http://www.flickr.com/photos/mrigneous/sets/72157618866005190/

So now... Who wants it next?

LocalHackday May 30th

2009-05-06T14:52:00.000-07:00

Joe Gray has been running an open lab night at 911 media arts center for quite a while now. I have been talking up the idea of an Arduino Hackday, and it seems like a natural combination. So on May 30th we are going to have an ~~Open~~ LocalHackday in the "lab" at 911. Bring your projects, bring your tools, bring your toys. Meet other local hardware hackers, artists, and makers. There won't be a formal leader, and it is not a class, but you will definitely learn something!

For me, the focus is going to be on Arduino projects, but that does not preclude you from bringing whatever you are working on.
Just show up!

I have also set up a google group for announcements of other similar upcoming events only:
http://groups.google.com/group/seattle-open-hackday

Here are the details:

Saturday May 30th 2:00PM - 5:00PM
911 Media Arts Center
402 9th Ave N.
Seattle, WA 98109

The event is FREE but I am suggesting a minimum donation of $5.00 to help 911 and defray their costs a little.

If you have questions email me at openhackday [at] gmail

looking ahead

2009-03-25T17:57:00.000-07:00

It has been a crazy few months here and I have barely had time to breath let alone work on projects or blog.

Work kept me tied to the keyboard for most of January, and all of February, and then I buzzed off to SXSW interactive for a week of sessions, schmoozing, and beer. Now I am getting really excited about some things that are happening this spring and summer.

First off I am teaching another Arduino class at 911 Media Arts Center starting sometime in mid April (exact date TBD, watch this space).

Then at the end of April I am going to be helping out with the next iteration of IgniteSeattle.

In June will be the opening of the 4th edition of the dorkbot-sea art show "People doing strange things with electricity" at 911 Media. This year I am collaborating on a piece for the show with my friend Bob Gallup.

Finally in July we are launching a really exciting event.
July 11th will be the first Frayed Wire art/tech unconference, and it should be a weekend of great fun (http://www.frayedwire.com).

I think I should have some interesting posts in store on motor control and arduino experiments as Bob and I work on the piece for PDSTWE. We are going to be using processing or vvv for video analysis and talking to the arduinos (or maybe one of my makecontrollers) via OSC or something. Details are sketchy but I know it will be fun.

The Arduino class is over.

2008-12-11T15:51:00.001-08:00

Arduino class day 4.

What a great class.
I really appreciate that these busy people were able to come in on Tuesday nights and still be creative.

On reflection the whole "tear apart an ink jet and build something" goal might have been a little bit too ambitious. In the end only one person ended up using the parts to make their project.
Perhaps a straight up motor control class without the recycle/reuse bit would have been better.

The stand out project was the bell ringer that Scott Nance is working on.
He built an amazing set up with the arduino running out to multiple shift registers with transistors on the register output pins to switch an external power supply through the solenoids. The mechanical quality (I did not even get any pictures of the beutiful little spring returned hammers he fabricated) plus the electronics just blew me away.
I think he might have done this before.

Everyone seemed to learn something, and they all managed to get their projects at least started.
I think perhaps that two solid nights just for project construction would have made things easier.

The good people at 911 media arts center tell me that they already have 5 people on a wait list for the next class. This means I get to experiment on a new group of students some time this spring.

In the mean time I need to make some projects of my own!

Here are some little videos I shot of the things that folks were working on.

My thanks to 911 Media Arts Center and the class.

re-write URLs under IIS for Drupal

2008-11-22T12:13:00.000-08:00

This is mainly a note to myself, but perhaps it wil help someone else as well.
Although all of the sites I work on end up being hosted under LAMP, I develop most of them locally on my XP machine using the built in IIS for localhost.

The only problem I have ever run into (well once I got the whole thing working anyway) is that IIS does not have URL rewriting, and without rewriting there are no clean-urls, and without clean-urls there is no services/AMFPHP.

I just ran across this node http://drupal.org/node/149318 that mentions an OPEN SOURCE Isapi rewrite filter (http://www.codeplex.com/IIRF).
Cool!

Now to install and test it out.
More info will be forthcoming.

dorkbot kit night and make blog Woot!

2008-11-05T08:19:00.000-08:00

Tonight is kit night at Dorkbot-sea. We sold kits for building solar theremins, tv-b-gones, and BEAM "robots". We wanted to raise some funds to buy tools for our gracious hosts at the 911 Media Arts Center (who "coincidentally" are running the Arduino class I am teaching). That was a complete success, and we now have 10 shiny new soldering irons, third hands, breadboards, and some basic hand tools. We are going to be using them tonight to put the kits together, and then they go to 911 for classes and workshops (and hopefully future Dorkbot meetings).

Oh and it looks like my motor control made the Make blog!

Arduino and motor control part 2

2008-11-03T22:07:00.000-08:00

arduino linear positioning with an ink jet printer carcass from Josh Kopel on Vimeo.
I spent a bit more time messing with the ink jet guts, and finally had some success getting the linear print head positioning to work. The first challenge was that the motor kept hanging up and moving in big jerks. After burning my finger on the Arduino's voltage regulator, I finally realized that routing all the power through the Arduino was the problem. Now I am running the Arduino off of the USB cable, and I hooked a random 13.5 volt wall wart up directly to the power terminals on the motor control board. Once I got enough torque out of the motor it works quite well.

I am getting a measure of the upcoming challenges though. For one I need to add at least one limit switch so that I can establish a repeatable zero position. That should be fairly easy.

I think there may be a bigger problem dealing with the interrupts from the encoder circuit. When I try to get any feedback from Serial.print() inside my loop{} it hangs up and stutters out only an occasional message. The issue seems to be that the encoder is too precise! The encoder strip has 200 line per inch rulings, and I am currently triggering an interrupt with each 0 ->1 and 1->0 transition. This means it is generating interrupt hits 400 times for each inch it travels, and I think the Arduino is never able to get through a complete loop execution without being interrupted (I can sympathize).

I am going to try just using one of the edge transitions (i.e. low -> high) and see if that helps. It may mean that the code needs to handle the rapid interrupts more gracefully. I can see this being with a very tight loop while the motor is seeking, and then a detachInterrupt() and power down (or set to shorted out braking) while it does anything else.

In the mean time it is fun to zip the motor back and forth.

Using a DC motor as a servo with PID control (part 1)

2008-10-25T18:09:00.000-07:00

PID motor control with an Arduino from Josh Kopel on Vimeo.

I found that the newer ink jet printers often use a combination of a DC motor and an optical encoder to take the place of stepper motors for print head positioning (linear motion) and paper feed (rotary positioning). The pieces often come out (after some effort) as a whole, and they seemed like a natural to experiment with.

The motors themselves are pretty nice if you just want to make something move and control its speed, and in combination with the encoder, I thought I could use them as a free alternative to a hobby servo. I knew there had to be some information out there about using a feedback loop to position a motor, and of course there was. It turns out that the classic way of doing this is through a PID servo controller (Proportional, Integral, Derivative). At its simplest this method can be thought of as a way to use the difference between where the motor should be and where it is (error), plus the speed at which the error is changing, plus the sum of past errors to manage the speed and direction that the motor is turning.

Ok, so I have to say at this point, that I am not an engineer. I did take an engineering calc. class or two, but that was more then 25 years ago, and I never much understood it even then. So all I really have to go on is my intuition about how this is working, a few good explanations, and some example code. As always , Google is your friend. If you do have a good understanding I would welcome your comments!

The first resource I found was this exchange on the Arduino forums and then followed through to an article that really explained what was going on here at embedded.com.

After reading the embedded.com article a few times I put together some simple code, and was amazed to find that the thing worked almost perfectly the first time.
The key elements of the code look like this

int val = analogRead(potPin); // read the potentiometer value (0 - 1023)
int target = map(val, 0, 1023, 0, 3600);// set the seek to target by mapping the potentiometer range to the encoder max count
int error = encoder0Pos - target; // find the error term = current position - target
// generalized PID formula
//correction = Kp * error + Kd * (error - prevError) + kI * (sum of errors)

// calculate a motor speed for the current conditions
int motorSpeed = KP * error;
motorSpeed += KD * (error - lastError);
motorSpeed += KI * (sumError);
// set the last and sumerrors for next loop iteration
lastError = error;
sumError += error;

What is going on here is:
1. read a value from the potentiometer through an analog to digital input (0-1023)

2. map that value so that it lives in the range from 0-3600 (the count from one full rotation of the motor). We need to scale like this so we can make an apples to apples comparison with the current position reported by the optical encoder. The current position is being calculated in another function (an ISR) whenever an interrupt is generated by the optical encoder (more on what this is all about here).

3. create an error term by subtracting the value we want to go to (target) from where we are (encoder0Pos)

4. multiply the error by a constant (proportional gain) to make it large enough to effect the speed. This is the Proportional term, and gives us a simple linear speed value. Basically it says that the further we are from where we want to be, the faster we need to go to get there. The converse is true, so that we will slow down as we approach our destination. Of course, if we are going to fast to begin with, we may overshoot. Then the Proportional will switch signs (from - to + or visa versa) and we will back up towards our target. If the speed is really off then we end up zooming past many times and oscillating until we (hopefully) get to the target.

5. add the difference between the error NOW and the error from the last time around. This is a way to figure out how fast the error is changing, and is the Derivative term of the equation, and you can think of it a bit like looking into the future. If the error rate is changing fast then we are getting close to where we want to be FAST and we should think about slowing down. This helps dampen the oscillation from the position term by trying to slow us down faster if we are approaching the target too quickly. Again, we multiply the value by a constant to amplify it enough to matter.

6. lastly add in the sum of all past errors multiplied by a constant gain. This is the Integral term, and is like looking at our past performance and learning from our mistakes. The further off we were before, the bigger this value will be. If we were going too fast then it will try to slow us, if to slowly, then it speeds us up.

7. set the lastError to the current error, and add the current error to our sum.

The resulting motorSpeed value will be a signed integer. Since the Adafruit controller takes an unsigned int as its speed value I do a little more manipulation to figure out the direction and get a abs() value for the speed, but that part is all pretty easy.

As I said, it seems really simple for such a complicated process. It turns out that the geared motor from the ink jets is much easier to control that some other mechanical systems. The physics of its gears, and the performance curve of the simple DC motor mean that you can be pretty far off on your tuning and it will still end up in the right place (eventually). If we were trying to do extremely precise positioning, or make it all work really fast, or handle huge inertial loads, then it would need to be a lot more robust. I am still working on "tuning " the configuration (i.e. slowly changing the 3 constant parameters one-by-one until it works best) and I will write more about that later.

In the mean time here is the code. Bear in mind that it is designed for use with the Adafruit controller and library. You will also most likely find that it does not work well with the constants I have chosen*. In that case you will need to do some tuning yourself. Stay tuned (hah) and I will show you how I did it.

*discerning readers of code will notice that the Kd constant is 0 meaning that this is actually a PI controller. I found that while the Derivative made the motor settle into position faster, it also injected an enormous amount of noise and jitter. This is due in part to the cheap, noisy, and non-linear potentiometer I am using. I need to do some more experimenting before I can really call it a complete PID.

Oh yeah, if you are taking apart an ink jet you may find these Optical Encoder datasheets to be valuable. These are specific to Agilent parts, but I have found they all share pretty much the same pin-outs.
http://pdf1.alldatasheet.com/datasheet-pdf/view/164530/HP/HEDS-9710.html
http://pdf1.alldatasheet.com/datasheet-pdf/view/163090/HP/HEDS-974X.html

useful bits

2008-10-20T10:33:00.001-07:00

useful bits,
originally uploaded by jak.

finally started tearing into the ink jet pile looking for useful parts and working on examples for the class. The first victim was a fancy HP all-in-one model. It consisted of a scanner and color printer and had sd and flash card sockets built in.It turned out to be extremely easy to tear apart. There was exactly one size of torx screw involved and only about 15 of them used. The rest is just intricate plastic snap together, which obviously means snap apart as well. I had to exercise some caution in not breaking the little tabs to make sure I would be able to reuse some of the connecting parts.

The main goals were to strip out the paper feed mechanism with its associated rotary encoding wheel and optical encoder, and get down to the linear print head driver with its position sensor/encoder strip. Along the way I also uncovered a small motor and encoder wheel in the ink waste tray, and the stepper motor for the scanner head. this last was especially nice as it came out with its gears, belt drive, and linear bearing axle in one unit. I took some not very useful pictures to document the teardown: http://www.flickr.com/photos/mrigneous/sets/72157608191419120/

I already have the paper feed motor running off the Adafruit motor shield and am working on how to connect the quadrature encoder to measure angle and direction of motion. The encoder device itself is dead simple to use as it is on its own little breakout board and only requires 4 wires +, GND, and two channels of signal (so only 2 i/o pins on the arduino). The challenge I am facing is figuring out which pins are used by the motor shield, and if they are the ones that support the interrupt(s) I need to manage the encoder. I will post more pics and code as I get that worked out. If I am successful (fingers crossed) then the same should be usable for the linear mechanism of the print head. In the end I hope to have a general purpose set up for reusing printer internals.

I also took apart an old lexmark printer and it had a very simple stepper controlled print head. The Motor shield really shines here as it took me all of five minutes to get the stripped down print head shuttling back and forth with microstepped accuracy and smoothness. I took a little video (not much plot, but there ya go).

get back in there

2008-09-17T13:38:00.000-07:00

Somewhere a grindstone is spinning and my nose hurts just thinking about it.
It has been a good solid 2 months of non-stop home renovation, code sprint, client support, and acclimatization.
We finally have a working kitchen, a bedroom above ground, and a sense of where things are in the neighborhood.
I have been really enjoying the process.
I think.
Perhaps I am just numb.
In either case I am looking forward to some new developments.
I made contact with the good folks at 911 media arts center (http://www.911media.org/) and we are going to be offering an Arduino class in November. They did an introductory class a few months ago and it apparently went very well.
So my goal is to push one of my favorite agendas and get some creative re-use into the mix.
We are going to be tearing down old printers and using the guts to build our projects.
I think I will order motor shields from adafruit.com and supplement the parts kit with a few extra sensors.

Over the next few weeks I need to start testing bits and pieces of printers to get a toolkit of code/method for folks to use as a starting point.
I am especially interested in using the optical sensors that provide linear and rotational position sensing in most ink jets.
The sensor spits out a quadruature encoded signal from a very accurately ruled piece of film (either round or a long strip).
I am hoping we can use it to make some interesting feedback mechanisms.
I really can't wait to get going on it but I need to clear off a little corner of the garage.
That alone could take a while...

slowly working our way out of the basement

2008-08-08T22:06:00.001-07:00

The flooring installer comes tomorrow.
I cannot contain my excitement.
To be able to stroll through the house without being able to see light coming up through the sub-floor... this is progress!
Drywall dust still cakes every surface, and there are long tails of romex extruding from every naked electrical box, but still it is PROGRESS.

On the plus side the basement is not so bad.
Or at least that is what we keep telling ourselves.
The weather has been fabulous.
Paying work has been falling from the sky.
Rae got a really really cool job (at a chocolate factory no less!).
And I got to present at dorkbot.

Yes, things could be much worse.

If only I could start getting the garage shop set up.
Why, life would be peachy indeed.

made it

2008-05-20T06:50:00.000-07:00

It took ~~eight~~ nine days to drive 3,358 miles (it was not the most direct route). Nine days in the car with my beloved and all the stuff we thought we would need for the next four months. Stuffed. In. The. Car.

In the end I have to say it was a great way to get here (Seattle). A plane ride would have been way too abrupt. Given the hyper-kinetic activity of the last few months (sell house, sell cars, sell possessions, pack house, say goodbye, leave) we needed some time to adjust to all the big changes. We needed time for a few melt-downs and some transcendent vistas. We got both (with the Spam museum as an added bonus). We got to see some of our far flung friends and family. We got to talk about the future and everything else we often don't have time for. In the end, we got to Seattle. We are now ensconced in our little apartment while we unscramble our brains and figure out what needs doing when. Tomorrow the house hunting begins with the inimitable Austin Chester (real estate agent extraordinaire). I am looking forward to it.

For a few pictures I give you Rae's flickr feed. I just want to point out that I took some of those, but not any of the really good ones.

the long road to Seattle

2008-03-15T14:14:00.000-07:00

All my electronics tools are packed away. The work bench is taken apart. I am painting my office (last room in the house!). Two weeks left to get prepared. We list the house April first (fools!).

Then and only then will I be able to get downtown and start packing the studio.
Of all the things you can do as an accumulator, moving across the country might just be one of the most painful. There is only so much you can take with you, and the rest has to disappear. I am planning a major studio sale (stay tuned junk fans) and intend to bequeath whatever might be of use to the hacktory, but in the end I know I will have to throw some stuff out. And that my friends is just not something I want to think about right now.

The only thing that keeps me from despair is Rae's promise that Seattle will have fun junk too. I trust her. Junk happens.

exhaustion

2008-02-20T21:11:00.000-08:00

Ignite Seattle was a blast!
Everyone who spoke was really good, and there were a few true standouts.
I can't wait for the video to get posted, although I dread seeing myself.

I really want to thank Brady Forrest and the good folks at O’Reilly for putting it on and giving me the chance to expound on MakePhilly.

Now about the title...
We have been in Seattle since Saturday and by the time we leave on Friday we will have:

seen 15 houses with our realtor
had (a combined) 6 job interviews (or a reasonable facsimile there of)
and driven untold miles looking at neighborhoods.
delivered 1 Ignite Seattle talk
visited relatives
caught up with friends

I need to go home and sleep for a week.
I am getting very excited about moving though!

crazy

2008-02-18T10:28:00.000-08:00

So Rae and I are in Seattle on reconnaissance for our move this spring.
Looking at real estate, trying to do some professional networking, trying not to go insane from the expanding possibilities.

I found out last night that I landed a talk for the upcoming Ignite Seattle on Tuesday (that by the way is tomorrow). Very exciting!
My topic is "fun without function" and I am going to present the codification of our experiences with makephilly and the maker challenge. I am really looking forward to this!
It has been a while since I spoke to such a large crowd, and now is the nervous part. I know I can talk for 5 minutes, the real challenge is how to say it all in JUST 5 minutes. That and how to choose the best pictures (thanks flickr).

what is it?

2007-10-26T14:04:00.001-07:00

I do a lot of scrounging.
Admittedly I just like taking things apart, so the motivation is not always to get useful parts.
But once you have a large junk box full of old circuit boards you just know that one of them is carrying the part you need.

Conversely, I often find myself staring at a board and wondering "what the hell is that thing?"
I have a pretty good basic knowledge of electronics, and I think I can identify the general class of a part without much help, but there are always mystery items which need some research.
I like research.
What better way to waste time then by learning something?

Along the way I have collected a few links which I use to try and figure these little mysteries out.

Here are a few:

The impressive sounding FCIM Component Identification Tool it is at least 12 years out of date, but then a lot of the things I am scrounging from are old too. The site is hard core Web 1.0, and a little hard to navigate, but they show LOTS of useful info on package types, general usage guidelines, and part numbers.

For a newer resource that includes lots of surface mount (SMD) codes try TKB-4u (The Technical Knowledge Base for You!) which lists lots of codes, and some basic info on identifying those tiny parts.

There are more lists of SMD parts at TALKING ELECTRONICS as well as useful information on op-amps, voltage regulators, opto couplers, and some basic older ICs.

For semiconductors, once you have found the part number you will also need to know how to use it, and for that you need a data sheet. Data sheets are like gold. They have the pin out, all the power specs, timing data, and often a reference circuit you can use as a starting point for your own designs. Finding a data sheet for an older part can be difficult, and many of the site which claim to have them want to charge you for them. Some time ago I discovered All Data sheets and have rarely had to look anywhere else.

blue LED POV and the Diecimila hack

2007-09-28T08:15:00.000-07:00

I really wanted to make something cool with my new toys before the last make:philly meeting. I knew there was not much time, so I settled on a POV device. I figured that would be easy to show off, and would be a good way to interest people in the hacktory arduino/freeduino class. As it turned out, the hardware was the easy part. Here you see my attempts to get it to spell MAKE. Obviously I still had some work to do...

I found these great little smd leds on a junked keyboard pulled from the trash. Soldering them down with their individual current limiting resistors was a challenge. Unsoldering them from the keyboard was a nightmare! In the end I only ruined one. I really want to build a hot air rework unit.

Along the way I came across this post. Pure freakin' genius! I used an smd cap instead (because I had it and I am addicted to soldering tiny things), but other then that I can't add anything useful other then to say it works like a charm.

Doing it the hard way

2007-09-02T14:03:00.001-07:00

I ordered 4 bare bones arduino kits from Modern Devices. But in a moment of false economy decided not to order a USB < -- > TTL cable for them. Instead I decided that I would use some of the parts from the SMD grab bag I got ages ago and make one myself. My old laptop has a serial port, so I did not have to contend with USB, and it is "old tech" so there is lots of info out there.

Finding a suitable schematic was as easy as looking at the serial Arduino schematic and finding the rs232 input area. I rounded up all the parts, and used a peice of prototyping board designed for SMD parts from OnePas (http://www.onepasinc.com/). I also dug up a DB9 connector in a plastic box that had enough room for the tiny board I ended up with.

I have a desk mounted magnifier lamp (which had been in storage unused for 30 years!) and it turned out to be an absolute necessity. Soldering the parts down was surprisingly easy, but working without a design provided the usual set of challenges and opportunities for cursing.

In the end I got it all put together, but I simply could not get it to work. Two days of fiddling, finding mistakes, testing with the scope, trying different computers, and learning the intricacies of rs232 protocols left me no closer to a working cable. In a funk I ordered a USB cable from mouser, and almost gave up.

One final investigation finally revealed the problem. DB9 connectors are number as you look at the BACK not the FRONT! Switch one wire and suddenly the thing works like a charm. One of those things you just need to know.

It is probably the most expensive cable ever built, but I am quite happy with it.

down the rabbit hole again

2007-07-25T09:21:00.000-07:00

Why is it that every site requires a return to the beginning?
I am working on a new Drupal site for Rae's cousin who runs a small management consulting firm in Seattle.

It should be dead easy, right?
Just drop in a few modules, do some simple theme work, post to the host, and go get lunch.
Right.

Instead I am looking for a JQuery plugin that does dropdown menus cleanly, trying to remember if there was a reason I had not used the asset module last time around, fighting with CSS, and generally feeling unmotivated.
I suppose having a well thought out process and a set of standards would help.
Maybe next time.

oscilloscope

2007-07-17T20:34:00.000-07:00

After a few months of research and obsession I bought a scope.
I was getting frustrated with the levitator and thought that having better tools would help.
No, I am lying.

Really I just wanted one (and have wanted one for a very long time).
I certainly don't need to prove to anyone what a geek I am, but if I did this would be the way.
For $250 I got a 15 year old tektronixs 2246 from ebay. For those not up on their obsolete test equipment that is a 4 channel 100 mHz scope with built in multi-meter and various other measuring cusors.

With heart in mouth I waited the week it took to get here, wondering the whole time if I had thrown my money away on a door stop. Oscilloscopes are pretty complicated machines, and although I had learned that this was supposed to be a fairly rugged and reliable one, I was sure it was going to be broken. Fortunately it arrived in one piece with all functions seemingly intact.

Now I just have to figure out how to use it.

got my blog back!

2007-03-21T08:36:00.000-07:00

Somewhere in the heart of the google empire lives an evil gnome whose job it is to make things as complicated as possible.
This malicious individual got hold of my blog, noticed that I had not posted in a year or so, and decided to punish me by making it impossible to log in.
Well I showed them!
After many repeated attempts to gain access with every email address and password I have ever used, and after trying, exhausting, and cursing every help channel they offer (which did not take long).
I finally had a breakthrough!
Somehow my blog had become registered under an email address that does not even exist (to my knowledge), and I only discovered it by looking at the http headers being sent when I tried to log in.

In any case it is fixed now, and I have managed to migrate to the new blogger, and although I may not post for another year, I feel much better!

many more meters

2006-05-05T18:16:00.000-07:00

many more meters

So, it may seem as if I have a lot of meters, and perhaps I do. The funny thing is that in comparison to other things I collect, I don't have that many at all. These came from our excursion to the reningers flea market last weekend. Many aisle were walked, and much haggling ensued. At the end of the day I came home with a haul which these nice finds were just a small part of. I bought minnow traps, sand sieves, light fixtures, mould forms, and beat up bocce balls. Rae claims these shouldn't really count towards the weekly big magnet quota since they don't come from the studio. I feel that since they will end up at the studio, I am justified, and am merely capturing them in transit.

In either case it was a grand weekend for collecting. After returning from the countryside we went to get food at the co-op and stopped at a tag sale near by. I asked one of the ladies about a bunch of electronics and odd industrial looking stuff, and she responded by saying "you want that stuff? Please, take it"

Don't have to tell me twice. Turns out to be old mine safety equipment. CO dosimeters, noise dosimeters, odd measuring equipment, basically a jackpot. It is in pieces all over my desk now, and I am having a blast trying to figure out how it all works.

They thought it was their kid, but it was just a fluke.

2006-04-24T18:47:00.000-07:00

They thought it was their kid, but it was just a fluke.

Because some jokes are just too silly to resist. Even if I am the only one who will think it is funny.

Milli and Micro the Ampere family

2006-04-24T16:46:00.000-07:00

Milli and Micro the ampere family

Two classy old weston meters I got for a song on ebay (yes you can do that through paypal).
I can't imagine what I will do with them, but if I ever figure it out I know where to find them. Or not.

In the background is my mag-lev project.
If I ever get it cleaned up perhaps I will post about that too.

Week 2 (gear puller?)

2006-04-16T14:24:00.000-07:00

week2 (gear puller?)

At first I thought this was a valve spring compressor, but after closer examination I am not so sure. Perhaps a device for separating gears on a shaft?

In any case my friend Tom gifted it to me when we visited his lovely family in MI a few years ago. He had apparently saved it for me knowing that I would love it... and I do.

Forged steel about 7" by 2.5"

where to begin

2006-04-09T20:08:00.000-07:00

where to begin

Not really fair to count this shot against the weekly goal I guess, but I wanted to show the source. This is the "studio" I rent, which serves more as a storage space these days. After a brief flurry of artistic activity a few years ago, I went back to building web sites. So the output from the studio has dropped to (almost) zero. That has not stopped me from collecting though. Slowed me down a little, but only because I only get here to deliver things once a month or so, and R sees the stuff (and gives me a hard time) if my car gets too full.

A Big Magnet

2006-04-09T18:42:00.000-07:00

Many years ago I was a graduate student studying metalsmithing at Cranbrook. One day, one of my fellow students looked at my work area in dismay, and pronounced "It looks like there is a big magnet under there and all that shit just sticks to it."

I accumulate things.

Sometimes I make stuff out of them, but mostly not.

I think I have accumulated some really interesting stuff, and I intend to take pictures of one thing each week and post it here. I could go for a really long time at one a week, so maybe it will be more frequent, but probably not. We will see.

-jak