Engunneer's Perspective

Died in a knitting accident, revisited

2011-02-22T21:21:00.000-08:00

Finally, another reference to dying in a knitting accident - Who's line is it anyway had a do-wop song sketch where everyone but Colin had to sing about Cheryl dying in a tragic knitting accident.

Now I just need to find out if this was a new episode, and perhaps find a youtube clip

Pano Test

2009-07-13T08:40:00.000-07:00

This is one we took on our drive along Route 101 on the Oregon coast. (Low res version)

Electric Bike project part 2

2008-08-09T22:54:00.000-07:00

In short, It works. I actually meant to post this in August, but forgot.

Here's the pre-debug final assembly

The thumb lever is a touch far away, but still comfortable to use.

The drive side. We never actually did anything to attach the small pulley to the motor sprocket. It's just a taper press fit. We'll pin it if it has trouble, but it works so far after a few trips.

a view of the fender washer mounting method

Brian taking it out for a spin. He had some trouble, and we ended up moving the motor assembly closer to the seat to gain a small amount of tension in the chain.

The new motor position.

I don't think ther've been many problems since the last adjustment

It was alot of fun to tool around.

All in all, a good finished project. Good thing too, since I promised to buy it if it didn't work.

If I were to do this again, I might get a bigger battery pack, though range doesn't seem to be a problem. Also, Try not to have bolt heads intersecting with the chain. It doesn't work that way.

Electric Bike project part 1

2008-08-09T22:09:00.000-07:00

Brian and I decided to build him an electric bike conversion so he can ride his bike to work. The problem with the ride normally is a gigantic hill on the way home. Our goal was to boost him up the hills, while still allowing him to bike normally (except with a heavy bike).

We based the design off of Eric Peltzer's Electric Bicycle. We modified the design to take into account a few major differences. We didn't want to weld anything, we wanted it to be cheaper, and we have access to a waterjet cutter.

Brian purchased a XYD-13 motor kit, which is a 600W motor that normally goes on a Currie Electric scooter. It came with a speed controller, and we had an option for a twist grip, or a thumb control. We also ordered a shaft, bearings, etc from McMaster Carr, and a small set of 10Ah batteries and charger. If he doesn't get enough range on the bike, the plan is to upgrade the batteries.

The motor came with an excellent one-way clutch built into the sprocket. We decided to keep this, which allows the motor pulley to freewheel while the bike is being pedaled.

Last weekend, after we had waterjet out the motor assembly frame, we spent a few hours assembling:
Full Gallery Link
The motor assembly

Preparing the output scprocket

Mounting the output sprocket

The fruits of the days efforts

Remaining items:

modify and mount the smaller pulley
get shorter bolts for the output sprocket
find and mount the bike rack to hold everything up
install the batteries, controller, and thumb control

tgimboej

2008-07-10T20:42:00.000-07:00

or, the Great Internet Migratory Box of Electronics Junk. I've signed up in the box request section because you never know what you can find.

Things I may be able to add to boxes (pictures and more updates to come later):
Blank Circuit Boards (up to 15" on a side)
ICs of all flavors
Character LCDs
Old graphic LCDs (10+ inch)
Ubicom (Scenix, Parallax) SX chips

I probably have enough to start my own box.

Geohashing FAIL

2008-06-27T22:07:00.000-07:00

So, I've been wanting to do a Geohash for a while now. Particularly a Saturday 4:00 meetup. So where is the meetup this Sat? only 0.5 miles from my house! Yay!

View Larger Map
However, I FAIL because I'm going to be in Renton by 3:00. I should find some way to leave a note or something.
ARG.

Seattle Regional

2008-03-28T15:45:00.000-07:00

We had a great time at the Microsoft Seattle Regional. We placed 2nd out of 31, and we made it to the semi-finals. We had quite a few excellent matches, and I was very happy to have my friend Mike Bastoni in town to see it. I'll write more about it later, but I wanted to share this banner made by the database of TheBlueAlliance.net, which looks like a great resource for watching match videos of the events.

No video yet from the seattle event, but they are posting videos from all the events that have webcasts, and are actually only a few matches behind at any given moment. Be sure the check out the events live on webcast where possible. The Boston regional has some very strong teams at the top of the list, and a few matches in Hawaii today made it clear that there were a number of teams that had won previous regionals present.

Worlds are going to be exciting.

Gas Receipts

2008-03-06T21:39:00.001-08:00

I had a really bad habit of just keeping the gas receipts in the cupholder in our car. I finally brought them in and started recreating my old calculation spreadsheet. I even collected all the proper data on each receipt. Amazingly, I was only missing 3 receipts over the past year, and only one was damaged.

Google Spreadsheet

Yes, I had an entire year's worth of receipts in the cupholder. It was beginning to be difficult to shove more in.

Now I just need to find my old spreadsheet to recreate the first year or so of data. I think
I am missing all the data in between, though.

Verdict:
I am still averaging 47mpg in my 2005 Prius.

FIRST Robotics

2008-02-26T21:12:00.000-08:00

This weekend is the Portland Regional for the 2008 FIRST competition. Every year, the FIRST Game Design Committee (GDC) designs a new game for the competition. Starting when the game is announced (First Sat in Jan, usually), teams of high school students have 6.5 weeks to design, build, and ship a robot that can compete. The aim of this whole thing is to introduce students to the wonders of Engineering, and all the associated fiddly bits like accounting, planning, organization, purchasing, CAD, finance, etc. Basically, they get to be an engineering company for 6 weeks. Good teams will do all the backend planning and finance (read: fundraising) before the 6 week "build season" starts. To help get them through this (somewhat difficult) task, teams are encouraged to build relationships with real engineering or technical companies. They are also encouraged to partner with their suppliers for help, discounts, machining, etc. This is where I come in.

I am working once again with the Issaquah Robotics Societ y on the 2008 robot. In 2006, I was asked to cut a few parts for the team since I work at a waterjet manufacturer. Team 1318 had 4 waterjet parts on the robot that year. In 2007, we had over 40 waterjet parts, and we were able to cut many of them during a tour. The students had a great time visiting the plant, and the demonstration lab let us use the machine to cut a series of parts that were ready to mount directly on the robot. You can see many of the parts in my gallery (We are the robot with purple bumpers around the outside). Most of the waterjet parts were brackets, though the notable exceptions are all visible in this picture. All of the claw parts, the 1318 logo bracket at the apex of the arm, and the main arm drive sprocket are waterjet. Not visible are the custom shaft adapters and motor mounts in the shoulder mechanism.
At the Portland regional in 2007, we made it all the way to Semifinals without breaking a single thing once the competition started. we did have to tighten two set screws at some point. This inadvertently won us a "Cleanest Pit" award from a fellow team, since we never actually had to get tools out.

This year, we have a pretty revolutionary robot, I think. The 2008 competition (video above) has a few classes of robot that can compete; hurdler, herder, and what we call "rabbit". We are not expecting many rabbit class robots. A random survey of robots on youtube seems to agree. Our robot (with a Monty Python killer rabbit on top) is shown to the right. The entire chassis is one single waterjet plate, with all other things bolted to it. Th rabbit has over 60 waterjet parts, and most of them are not brackets, like last year. There are two of everything; custom sprockets, custom timing pulleys, motor mounting plates, copper slip rings, and a bunch of parts that I can give you our name for, but that won't mean anything (bridge plates, brush retainers, the sandwich (8 parts for each copy)).
In this second view, you can see more of the wheel modules. Each wheel module has two wheels (basically just a wide wheel) and a 6:1 ratio belt/pulley combo attached to a 3500RPM (under load) torque-y motor. each wheel module is rotated by a smaller motor, and can rotate continuously 360 degrees. this allows us to translate sideways, pirouette, drive forward, or any combination of the three.

I honestly can go on for hours about our robot and all the waterjet parts. (Reference this CAD model for a better view). But the reason I am so passionate about the FIRST robotics competition is actually really simple to explain. I graduated from high school after spending four (three technically) years on a FIRST team, went directly to engineering school, got a degree in Electromechanical Engineering, and got a decent engineering job pretty much directly out of college. (Not to mention the 2+ years I worked at iRobot while in college). The program really prepares students for the real world. FIRST isn't a perfect program, but the constraints it puts on a project are very realistic. We are just starting a new project at work that will be done in three months. It will be very fast paced, and many people have to work together to make it happen, while still managing everything else the normally do. This is exactly what I've been trained for, and this is exactly what I'm trying to impart to the students I work with. Even the equipment we make at work (the X-Y machine portion) is very similar to the robots they build. There is a central controller, some small motor controllers (amplifiers to the machining world), a few different types of motors and solenoids. Last year we had pneumatics, which our machines have. Many of the motors on the robots are even controlled with PID control algorithms, just like the equipment we make. A number of the students have learned embedded C, and all of our code is student written and maintained. All of our parts are designed first in CAD, prints are made and handed to other students to fabricate. Tolerances are discussed, changes are propagated back to the models, and the robot is assembled in a fairly controlled manner. If you didn't read the first part, then you may even think I am talking about a real engineering company.

The students in this program will graduate college and move on to deal with some of the problems facing the world today. These students will design wind turbine, more efficient cars, new space capsules, and all kinds of things I can't even think of.

That is the reason I support FIRST.

NASA kindly hosts the competition live as a webcast. Check this link on any Friday or Saturday in the next month or so to see live robot action.

You should also find and visit your local regional this year.

died in a blogging accident

2008-02-14T21:18:00.000-08:00

or, what browsers do xkcd readers use?

93% of my blog traffic comes from search engines. 89% of my search engine traffic comes from variations on "died in a knitting accident". It is safe to say that 100% of people who search for that either read xkcd, or are knitters who had someone force xkcd on them. I happen to have the browser data of the subset of people who read xkcd and needed to search to see what came up.

Without further ado, the results:

1.	Firefox / Windows	47.92%
2.	Internet Explorer / Windows	23.96%
3.	Firefox / Macintosh	9.27%
4.	Firefox / Linux	8.63%
5.	Safari / Macintosh	6.39%
6.	Opera / Windows	1.92%
7.	Mozilla / Linux	0.96%
8.	Firefox / (not set)	0.32%
9.	Firefox / SunOS	0.32%
10.	Mozilla / Windows	0.32%

I am thrilled that some nut visited using SunOS. Keep it up.
If you look at browser only:

1.	Firefox	66.45%
2.	Internet Explorer	23.96%
3.	Safari	6.39%
4.	Opera	1.92%
5.	Mozilla	1.28%

Compare with my wife's knitting blog:

1.	Internet Explorer	58.46%
2.	Firefox	36.92%
3.	Safari	3.85%
4.	Mozilla	0.77%

I'd also like to hear from the visitor who has a 3840 x 1200 desktop, though it may actually be my coworker with three screens at work.

1.	1024x768	29.07%
2.	1280x1024	21.41%
3.	1280x800	14.38%
4.	1440x900	8.63%
5.	1680x1050	8.31%
6.	1920x1200	4.79%
7.	1280x768	3.51%
8.	1600x1200	3.19%
9.	1400x1050	1.60%
10.	1152x864	1.28%
11.	800x600	0.96%
12.	1024x1280	0.64%
13.	1280x960	0.64%
14.	2560x1024	0.64%
15.	1280x854	0.32%
16.	1440x960	0.32%
17.	3840x1200	0.32%

Some people may need to be notified that computers do 32 bit color now....

1.	32-bit	79.87%
2.	24-bit	15.02%
3.	16-bit	5.11%

Conclusion: Google knows too much about you.

Corollary: I spend too much time looking at hit graphs

Luke

2008-02-07T22:52:00.000-08:00

My original engineering dream was to make robotic prosthetics. I still want to do this someday. Recently, Dean Kamen announced an Awesome robotic arm, called Luke.

Watch the video!

Finished_Projects--;

2008-02-07T22:30:00.000-08:00

The microscale may be dead. I think the bearing is sticking (for the second time). There can only be one solution to a mechanical problem... software! I tried to work around it in some interesting ways.

Adjust the indicator flag to be more like the original article
Adjust the flag most of the way to normal
Attempt to calculate the mass as a function of both the current force and the current error
Adjust the gain so that it moves faster
Adjust the gain so it moves more slowly
Adjust the gain so it moves WAY more slowly
Put the gain back where it was
Add 2 to the gain instead of 1
Undo
Stop averaging the last two error readings
Undo
On Even seconds, reduce the force by 5mg to break the friction
10mg?
15mg?
Undo back to 10mg
When seconds MOD 4 == 0, reduce the force, ==1 and ==2 go back to the regular force, ==3 actually try to balance
Same, but with MOD 5
Same, but break the 5 second cycle into 1,2,2 instead of 1,3,1 (Fake, recover, balance)
reduce the force by 20mg

So, after all that (half of which is in the SVN), It is repeatable to within +/- 0.3 mg (when it stabilizes), or it will flail around wildly +/- 70mg. The only difference between the two states is when you put the sample on the scale.

Possible "improvements"/Next Steps(that don't involve the 2kW heaters from the last UW project, just to see if they still can melt aluminum in 10 minutes)

replace the galvanometer
add springs to support the flag (stabilize)
make the moving parts lighter (reduces accuracy - HA!)
Realize that Erica can manually take the data faster than I can fix the scale
Offer to set up webcam and OCR the regular scale into data
Offer to write AHK script that will show pictures from the Nikon of the regular scale, so data entry is faster

Sigh...

(for those keeping track, Finished_Projects is now back to nil,m not counting FIRST)

Reprap

2008-02-02T20:12:00.000-08:00

I've been working for a little while with a couple other folks on a reprap. One thing we didn't like about the basic (Darwin) reprap is the large number of parts needed to make it (example). We started coming up with some ideas, and I was able to design a simple 3-axis gantry system that uses 11 copies of a simple printed block, and that's it. all other parts are non-printable, but simple, like threaded rod and bar stock. In theory, the reprap will have interchangeable heads, allowing extrusion, cutting, and maybe even laser cutting. I even want to make a low pressure waterjet, though the added complexity is not fun.

Current status:

I think one of the Johns is ordering parts.
The design needs to be adjusted to use less plastic per block.
Need to get the uBrain or some other motor controller working.
Someone needs to look at software to control this thing, but I guess building it comes first.

Idea: Someone needs to interface a reprap to BugLabs.net hardware.

We shipped your package 10 days ago...

2008-01-28T16:30:00.000-08:00

DHL needs to unclutter their email server. I ordered some ipod parts from rapidrepair.com, and have already received and installed them. I was somewhat surprised last week when Erica IM'd me to tell me a package had arrived. I was surprised, since I hadn't received a shipment notification... Until now

---------- Forwarded message ----------
From: <DHL-Notify@dhl.com>
Date: Jan 28, 2008 4:20 PM
Subject: DHL Shipment Notification - Waybill #[redacted]
To: engunneer@gmail.com

DHL EXPRESS
SHIPMENT NOTIFICATION

The following 1 piece(s) have been sent by Repair Dept. of Rapid Repair via DHL Express on January 18, 2008 using Waybill [redacted].

If you wish to track this (these) shipment(s) please contact your local DHL customer service office or visit the DHL Web Site at http://www.dhl-usa.com/

If you have a Web-enabled mail reader, click or copy the link in the web browser below to view shipment tracking details:
http://track.dhl-usa.com/atrknav.asp?ShipmentNumber=[redacted]
Sent To: Seattle, WA
98107
United States Of America

From: Rapid Repair
Repair Dept.
1825 W. Main St.
KALAMAZOO, MI
49006
United States Of America

Shipment Date: January 18, 2008
Delivery Date*: January 24, 2008
Weight: 1.0 LBS
Pieces: 1
Service: Ground
Note: Delivery times may vary, please visit www.dhl-usa.com for details.
Reference: [redacted]
Contents:
* Based on Shipment Date provided by sender

Thank you for requesting DHL Express
for your delivery needs.

Good job letting me know, DHL. At least the package arrived quickly in perfect shape.

Died in a knititng accident part 2

2008-01-16T19:51:00.000-08:00

Wow, apparently blogging about this particular xkcd comic is good for your google PageRank. I found another "blog" ( http://utenti.lycos.it/itosunit/2811/died-in-a-knitting-accident-xkcd.html ) that is even backdating posts about dying in various types of accidents. I wonder if these blogs just use jwz's DadaDodo nonsense generator to come up with this stuff. It comes up with things that almost make sense.

Other topics:
When will I learn that "a few more volts" can actually hurt something... For example, running a 12V scanner on 12VAC (a few years ago), or running a 12V scanner on 16V. Both appear to be bad ideas...

Died in a Knitting Accident

2008-01-11T08:54:00.001-08:00

xkcd is one of my favorite online comics. Today's comic is highly amusing, but alas, no longer valid. Amusingly, "Died in a knitting accident" seems to be the most checked, as well as the most bogged about. Slightly more amusingly, there is actually a spam-blog posting about dying in a knitting accident. ( http://ktvbcom.blogspot.com/2008/01/died-in-knitting-accident.html ). It even posted yesterday.

I hope the knitting community catches on.

Libretto

2008-01-04T21:03:00.000-08:00

We've been doing some cleanup at work, and our IT department was throwing out some old laptops (and I mean OLD). I managed to get my hands on a tiny little laptop called the Toshiba Libretto 100CT. I have always had a place in my heart for (old) palmtops. I've always wanted one. This is by far the best find I have had digging in old Tech. Even better than the Tandy 102 I never should have sold.

The laptop itself doesn't have many ports. The entire front panel is battery, the left side is blank (HDD and battery). The back has mini headphone and mic jacks (3/32"). The right side showed the most promise, having two cardslots and an IR port. That's it. No floppy, no serial, nothing. USB hadn't even been inventged yet. A bit of research online shows two different docking stations (connection on bottom), and an external floppy that uses a PCMCIA (People Can't Memorize Computer Industry Acronyms) card slot. They didn't have any accessories for it, so I took it as is.

Anyway, the laptop was worth $2500 when it came out in the late 90s. It's worth about $100 today. The charging plug was similar enough to one I made years ago for an old Gateway Solo P120, and I was able to adapt it to the libretto easily enough. I charged it overnight and then brought it to work. Lo and behold, it booted! on battery! It came up in Window 95 (ick!), and I found out that it belonged to the CEO (2 CEOs ago). He apparently bought it back in the $2500 days. I also found out that the battery was still good for 6-8 hours of minimal use uptime! Not bad for a 9-year old OEM battery. Part of the deal was that I agreed to kill the old hard drive in it.

I grabbed some other old hard drives I had, stuck them in various laptops that had CD drives, installed various OSes on them, and then tried them in the Libretto. WinXP was a joke. Win2K booted into a BSOD, and Linux looked like a nightmare based on what I'd read.

I bought a floppy drive (same model) on Ebay, so at least I had SOME way to talk to it.

Time passed...

I asked IT if they found any of the other bits to the mini laptop. They showed me into the closet where they had squirelled away a few other bits of ancient hardware for me. They found the floppy drive, and a docking station that said Toshiba, but was the wrong kind (looked like a 2001/2002 model). Now I have two floppy drives, but they think they through out the docking station, based on my description of it.

More time passes...

Last week, I decided to give it another go (with FIRST season fast approaching), borrowed my USB floppy drive from work, and started hacking. I managed to hook a new 4.1GB hard drive to my P4 2.8GHz laptop, booted to a 98 floppy, and had to remember how to use fdisk. I managed to get the drive ready, and copy over my old Win98 CD to the drive.

Yesterday morning, I booted to the hard drive in the libretto, ran windows setup, and had win98 booting by 8AM. A few hours later, I had the video driver fixed, the floppy going, a network card,n a serial port, firefox, autohotkey, and a few other programs all going.

Last night consisted of some fruitless attempts at 802.11 (I had suspected the card was bad before I started), so tonight I blog via a wire, but it's all written on the Libretto!

Firefox is slow, so I have to type in notepad for now. Pandora won't run (maybe it will with IE6 or IE5.5), and I can't play youtube videos (skipping). At least I should be able to program AVR and Stamps from it. That (in theory) is the reason I fixed it, so we'll see how it goes.

Build a photo studio - Collapsible Light Diffuser Frames

2007-12-30T11:37:00.000-08:00

I just published my first instructable, a collapsible light diffuser for photography.

Click here to go to the Instructable.
Click here to go to the photo gallery page.

I'll be posting some photos later that we took using this. We cataloged all of the knitting Erica has completed so far, and we wanted to make this for the photos.

Let me know what you think.

ah, math

2007-12-09T16:31:00.000-08:00

Look at the great bit of math the computer gave us for total travel time.

Flight to Boston
Flight: 2 Round-Trip Tickets
All flight times are local to each city.
______________________________

Seattle/Tacoma International Airport, (SEA) to Boston Logan International Airport, (BOS)

Flight: Alaska Airlines Flight 12 (on Boeing 737-800)
Depart: 08:45 AM, Seattle/Tacoma, WA (SEA)
Arrive: 05:03 PM, Boston, MA (BOS)

Total Travel Time: 8 hrs 18 mins
______________________________________________________

Boston Logan International Airport, (BOS) to Seattle/Tacoma International Airport, (SEA)

Flight: Alaska Airlines Flight 15 (on Boeing 737-800)
Depart: 06:05 PM, Boston, MA (BOS)
Arrive: 09:23 PM, Seattle/Tacoma, WA (SEA)

Total Travel Time: 3 hrs 18 mins

So, we're averaging 300 mph on the way there and 750 mph on the way back. (Keep in mind that Mach 1 is 761 mph). Air travel really is amazing these days.

Stupid, or just Crazy?

2007-12-09T16:06:00.001-08:00

I've been thinking more an=bout my PID motor controllers based on the ATtiny13, and have determined that I must be crazy. I did some googling, and everyone else that is making a motor controller using an AVR is using something like an ATmega168, an ATmega32, or other large controller (almost always a mega). The application note on Atmel's website (look for AVR221) doesn't recommend a certain controller at all. So am I crazy to try to shove this all into an tiny13? We'll see how it goes.

I went over to AVRfreaks.net to see if there is anything larger than the tiny13 that has the same pinout. It looks like I can use the ATtiny25, ATtiny45, or ATtiny85 for 2, 4, or 8kb of Flash space. Too bad I already bought a dozen tiny13 chips.

Project Lull

2007-12-05T21:45:00.000-08:00

I am officially in a project lull. The microscale is pretty much done (I do need to send it with Erica for final testing), and Robotics season is starting up in the first week of Jan. I theoretically have a week and a half that I could accomplish something with, but I don't have any good ideas.

My micromouse board is at a difficult point. I managed to set some of the fuses wrong, and now I can't talk to two of the three boards. I have one spare processor, so I could replace one, but TQFP-64 is no fun to remove from a board with no soldermask. The alternative is to guess what I set the fuses to, and try to generate the required clock long enough to make them normal again.

I could always work on the program for the micromouse motor controllers, since I have a few of those built up. I can always use an oragutan to test those. After the fun I had implementing PID, UART, and LCD code in an ATMEGA48 (4k codespace, 512B SRAM), it should be quite a bit of fun to put PID and UART into an ATTINY13 (1k codespace, 64B SRAM). at least most of the problem was LCD code. I also need to work in PWM for the speed control, but an interrupt should be able to handle that.

Possible control algorithm notes (while I'm thinking about it):
position registers are basis of PID

Current position
Final Target position
Moving Target position

"moving target" is how I can do speed control. It is the point that the PID errors are calculated against. It moves at a (likely) steady rate towards the Final Target. This is a place where I could put in some acceleration control, but codespace already seems at a premium. The rate at which it moves would be the speed command (counts per small unit of time). This might be the part where I find out why moving slowly is apparently difficult. We'll have to wait and see.

PID normally has just those three gains (P, I, D). I think I might want to try to implement some of the more complex gain types like velocity feed-forward.

This might be a good point to bring up the fact that I plan on using avr-gcc, and not learning assembly for AVR. (One of the best things Atmel has done is to build avr-gcc into AVR studio, IMHO.)

Perhaps I can find some time this week to work on the motor controllers. Remind me to post later about the design of the board itself, and some of the good and not-so-good things I learned while doing it. (Preview of not-so-good: For some reason, Atmel decided to make the SPI programming pins on an ATMEGA128 NOT the same as the normal SPI pins, which caused hours of frustration while debugging the first time I turned it on. Of course I used the SPI programming pins for some completely different function on the board.)

microscale parts list

2007-12-01T13:09:00.000-08:00

I saw a link on the MAKE:blog for Octopart, and though it might be a good way to publish a list of the parts I used in the microscale. The only thing I couldn't find was a simple cheap analog meter, like the one from Radio Shack.

powered by octopart

Blog Fodder

2007-12-01T13:07:00.000-08:00

Erica sent me an email titled Blog Fodder with some pictures of the microscale in action.

And she also gave me a nice graph of a few sample runs

It's clear that the scale can be improved, but is pretty close to working now. Erica brought it home for me to work on. I think I have enough code space left to add the Derivative and Integral terms back into the PID loop, which should make it less noisy.

I also want to compensate for flag position in the final readout formula, so it can predict what the mass would be if it were perfectly balanced. This part is harder, and I'm not sure if it's needed.

Alaska

2007-11-26T21:48:00.001-08:00

Ok, so the pictures are a year old, but I haven't done a photography post yet. These were all taken before we got the Nikon D80 (which I will post about later). These are taken with a Sony DSC-F828. We got the camera used on craigslist for $650, including some memory, the bag, a macro lens, and a wide angle.
I feel like this camera gets you as close to a DSLR as you can without having the ability to change lenses. the 28-135mm that is built in is pretty nice. It also can take our 2.2x teleconverter, though not without severe vignetting (See example below).

Yes, I do like sun flares. Why do you ask?

These photos are not color corrected.

Overall, we took over 2500 photos over two weeks. We tossed about 20% out of the box due to being blurry, having no interest, or being otherwise BAD. Of the remaining 2000, we deemed 273 to be worth showing off. Full galleries: Picasaweb, or Gallery. Only Gallery has the panoramas.

The D80 with our 70-300mm lens can take the 2.2x teleconvertion lens without vignetting.

I welcome comments on any of my photos. It's a hobby, and I can put a certain image under Creative Commons, but please request first.

Microscale documentation

2007-11-26T09:18:00.000-08:00

This document describes how to use the microscale.

Powering Up

- Boot the computer.
- Open microscale.ht on the desktop.
- Turn on the scale by moving the switch to the right. The LCD should turn on in about a second, and the scale will start balancing.

Calibration

- Zero the scale, by typing z into the terminal window. The Zero value can be adjusted manually via the [ and ] keys. The zeropoint is shown on the LCD's top row.
- Place a 100mg mass on the scale, wait for it to balance (about 10 seconds).
- Adjust the slope until the readout is close to 100mg, using the + and - keys.
- Verify the calibration with a smaller mass.
- Verify the zeropoint with no weight on the scale.
- Type s in the terminal window to save the calibration. This calibration will automatically be recalled next time the scale is powered on.
- To reduce the noise during the calibration, you can reduce the gain on the scale. The gain is controlled with the , and . keys (, decreases)

Operation

- Type h into the terminal if the scale is currently sending data to the laptop.
- Select the Transfer menu, Capture Text.... If a submenu pops up, choose Stop, then repeat this step.
- Choose where you want the data saved. The current default is under My Documentsmicroscale data. The file should have a .txt extension, but that is not required.
- The scale is now ready to record. Type r into the terminal just before the sample is started. The scale will reset the seconds counter to 0 and send a header row to the screen, followed by data every second.
- When the sample is finished, type h into the terminal to stop the data.
- From the Transfer menu, choose Capture Text, Stop. The file is now ready to be moved to another computer or opened in Excel.

Data format

- Column 1 is the time since r was last pressed.
- Column 2 is the temperature in C at the interface Circuit board.
- Column 3 is the calibrated reading in milligrams.
- Column 4 is the analog reading of the flag position. 512 is "balanced". If this reading is within 524 to 500, the scale is getting a reasonably good reading.
- Column 5 is the number of counts being applied to the DAC beyond the zeropoint. It is only here so that a bad calibration can be fixed after the measurement is taken.

Notes

- The data can be made less noisy by adjusting the gain down. The cost is a slower response time.
- Gain can be adjusted on the fly during a reading with no side effects.
- The gain is saved with other calibration data when s is typed.
- It may be a good idea to write down the calibration data for a particular run, as a backup.

Jumping Kittens

2007-11-25T21:27:00.000-08:00

This summer, we fostered some kittens for the Seattle animal shelter. The last set were particularly energetic, and I was able to get some good shots of them in mid-air, chasing a feather toy. Here's a link to the flickr set, and the gallery page (pages 6 through 11).

Some of my favorites:

Ok, so they are all my favorites...

Handwarmers

2007-11-25T21:02:00.001-08:00

Erica made me some really soft Alpaca handwarmers. They are really warm too. I'll be using them every morning on my commute. She's also working on a matching scarf.

Link (towards the end)

Microscale v2.5

2007-11-18T17:37:00.000-08:00

I meant to be writing about this as it happened, but instead I will summarize. After the last attempt, we decided to make the scale out of metal, so it would be a bit more robust. The new version was designed in Solidworks in about a day, ported over to FlowMaster, and cut on a waterjet at work. The waterjet process took all of two hours, including polishing. The cut itself was around 7 minutes. Sadly, I didn't take any pictures of the individual pieces, but the final assembly photos are nice.

The scale is made out of 1/4" Aluminum. I hand drilled and tapped all the holes with bad equipment. The tap actually twisted if I applied too much torque. It's quite possibly the cheapest. tap. ever. At least it didn't break on me. I did break a screw that I was using to clean up the holes, but it wasn't strictly required, right? You can just make out the copper wire counterweight on the lower right side of the assembly. It's the hokiest part of the design, but it works.

Here's the best view you'll get of the new flag design.

The idea is that when it is centered, the IR beam is half blocked. When the arm is off balance, the changing radius of the flag blocks more or less than half of the beam. The advantage is that the arm can move up to 5 times further than it could before and still get a valid reading. The flag was drawn in Solidworks and cut out of 0.06" Aluminum on the waterjet. I then polished the cut face to make readings a little more consistent. There is an adjustable block above and below to limit the motion of the arm, and to protect the flag in general. Th flag hitting the lower stop actually makes me think of the big hammering guy sculpture out in front of SAM.

While assembling and tweaking the new flag design (using the capacitor as a simulated sample), I somehow damaged the galvanometer itself. It got really sticky, and would stay in the balanced position without being balanced. We ended up heading out to Radio Shack to get a new one (and another spare) for ~$16 each. While I was at it, I made the arm longer by about 50%, bringing the scale to about 150 counts per milligram. The longer arm and new flag allowed me to re-tune it to respond faster.

Here's a picture of the computer taking data via hyperterminal. The serial stram is simply recorded to a text file, and can be imported directly into Excel later.

Note: Remember to ask Erica for a picture of the scale in use, and a screenshot of the resulting graph.

Also, while trying to fix the balance arm, the screen went blank! It was fairly easy to trace. The scale still worked, but the negative voltage for LCD contrast went away. The only problem with having a donated collection of stashed parts is that the parts are old, and actually require some work to make them function. Current LCDs are fine with ground on the contrast pin, but older ones want -3 to -10 volts. Fortunately enough, the MAX233 creates -10 volts for itself to use for RS-232 communication. Since it's just a tiny load, I ran the LCD contrast to this supply. The problem turned out to be a fleck of loose solder shorting out the supply. Good thing the Max233 is resilient.

I'm calling it done at this point (Hence the completed tag). Erica's brought it to school, and she'll calibrate and tell me how it goes. It's version 2.5 because of all the mechanical upgrades, though the code is essentially the same as the v2.0.

Now for the next project...

MicroScale v2.0

2007-11-17T22:13:00.000-08:00

Erica found an article at Scientific American describing how to make a small micro-gram balance using a part ripped from an analog multimeter and some other electronics.

I love voiding warranties.

I first built the "manual" version, and we were able to detect the change of mass by adding individual grains of salt to the scale. Each one caused a 0.004 volt change on the sensing voltmeter. Using this info, and some of the ideas from the automatic version, I proceeded to make my own version of the PID controlled scale.

I used an Atmel Mega48, and a tweaked version of the Orangutan Library for Pololu. I can get away with this because I bought a Baby Orangutan and a regular Orangutan controller from them at Robothon 2007. I did the first prototype of the code in the Baby O processor, but then decided I wanted it for another project. The Mega48 is smaller, but otherwise identical to the Mega168. I added a few routines to the LCD code, and patterned my UART functions off of the same.

I tried a new wiring technique on the circuit board for this project (jumpers on top), and didn't really like it that much. I'll go back to pseudo-traces on the next project.

You can't see much in that photo, but I am using A MAX233 for RS-232 conversion, as well as creating some negative voltage for LCD contrast (It's an OLD LCD. Newer ones only need Ground for contrast). I also have a 5 volt precision reference (MAX675), a really nice 16-bit DAC (MAX541), and a basic Quad Op-Amp for amplification. The closed box looks WAY better, don't you think?

Shown on the screen is a very early version of the code. Here is the mounting arrangement for the scale itself. You can see I took a slightly different tack that the original article, but have borrowed some ideas from them. The coil on the right is actually a counterweight, to (mostly) offset the weight of the glass coverslip and holder.

In the next update, I should have an actual measurement and some code details.

Blogging @ Home

2007-11-17T21:19:00.000-08:00

This week, my wife decided to start blogging, (knittingfreestyle.blogspot.com), so I decided to revive my old, disused blog. I theoretically will blog about my current robotics and electronics projects, as well as other random things. We've added her name to the waiting list for ravelry.com, so we'll see how that goes. I wish I had something like ravelry for electronics and projects... too bad I don't know how to develop for the web.

MPAA WHAT?

2006-11-28T20:49:00.000-08:00

From this article:
http://www.bbspot.com/News/2006/11/home-theater-regulations.html

MPAA Lobbying for Home Theater Regulations
By Scott Small
Los Angeles , CA - The MPAA is lobbying congress to push through a new
bill that would make unauthorized home theaters illegal. The group
feels that all theaters should be sanctioned, whether they be
commercial settings or at home.
MPAA head Dan Glickman says this needs to be regulated before things
start getting too far out of control, "We didn't act early enough with
the online sharing of our copyrighted content. This time we're not
making the same mistake. We have a right to know what's showing in a
theater."
The bill would require that any hardware manufactured in the future
contain technology that tells the MPAA directly of what is being shown
and specific details on the audience. The data would be gathered using
various motion sensors and biometric technology.
The MPAA defines a home theater as any home with a television larger
than 29" with stereo sound and at least two comfortable chairs, couch,
or futon. Anyone with a home theater would need to pay a $50
registration fee with the MPAA or face fines up to $500,000 per movie
shown.
Related News
"Just because you buy a DVD to watch at home doesn't give you the
right to invite friends over to watch it too. That's a violation of
copyright and denies us the revenue that would be generated from DVD
sales to your friends," said Glickman. "Ideally we expect each viewer
to have their own copy of the DVD, but we realize that isn't always
feasible. The registration fee is a fair compromise.
The bill also stipulates that any existing home theaters be
retrofitted with the technology or else the owner is responsible for
directly informing the MPAA and receiving approval before each
viewing.

What the heck are they thinking?
1) Aren't they "not acting early enough" on this too? Even I have a
screen larger than 29", and I don't even have a TV! What about
Conference Rooms at work? what about people with the 30" Mac screens?
2) They want every one of our friends to own the DVD so they can come
watch it? I bet they want rental places to go out of business too.
I've seen tons of movies, but we don't own a single DVD.
3) How do they expect to enforce a retrofit of millions of TVs and
homes. Maybe they want to put a camera in evey living room. How bout
planting a bug in every DVD case, so they can track them with GPS.

Someone elect somebody who will stand up to this! Now! Call your
congress critter!

Random mail archive

2005-02-16T13:06:00.000-08:00

Basically, I got a piece of spam today, and decided to see how many versions of it google can find. Google Results 1.
The first result looked interesting: Nokia mailing list archive of similar message.
Changing the message number gave an amusing cross section of the kinds of spam that this particular mailing list gets. This is apparently some kind of developers list that seems fairly open, and around the 800th message, they got put on a spam list. Going up a few levels revealed some more archives, which may be amusing for someone to look through. I'd love to see some comments posted about what was found.

See also: http://www-nrc.nokia.com/mail-archive/ext-ip-location/ starting at message 803, the signal to noise ratio goes haywire.

Avacado Sushi

2005-02-06T22:22:00.000-08:00

Bought a book for my wife two Christmases ago. Been having sushi quite a bit since then. Hard thing to do is find a good source of nori (seaweed).

See more progress on: learn to make sushi

If not the end, at least the fixing

2004-12-16T14:11:00.000-08:00

I can't tell you how many things are broken in IE. I currently use Firefox, and it's great. A few crummy sites won't render properly in Firefox (because the site does not follow established standards) and I have to use IE to do anything on the site. All of my online banking works in firefox though.

Long live W3C compliant browsers!

(See more progress on "witness the end of IE"...)

Damn Flu

2004-12-16T13:56:00.000-08:00

Waking up at 4:30 in the morning throwing up really sucks. One good day of sleeping it off should fix this, right?

(See more progress on "get over being sick"...)

Just before College

2004-12-15T20:19:00.000-08:00

I got to spend two weeks in Japan, four days in Kyoto, and ten in Shichigahama, which is my old town's sister town. Japan was great. I think I was most impressed by the street braile. I used it for about three blocks walking around in Sendai. Once you get used to it, you can get anywhere.

In Japan, they look at you oddly when you take steps two or three at a time.

(See more progress on "Visit Japan"...)

Crazy night last winter

2004-12-15T20:16:00.000-08:00

I don't remember exactly when, but Boston got to see some of the Northern lights last year. There was this faint deep red tint to the sky, and it wasn't smog or sunset. It was darn cool. I want to go to Alaska and see them there.

(See more progress on "see the northern lights"...)

Just starting out

2004-12-15T20:12:00.000-08:00

I managed to get my Palm to send email to my blog, so I can write on the go without an internet connection, but I haven't done it yet. Now my blog is mostly populated with things I want to do from 43things. (see link below for more on 43 things). I guess that means I have two blogs. Three if you count my home server (which is down right now because PostNuke won't talk to MySQL all of a sudden). AND I'm trying to make tiki-wiki work with my site too, and I'm just not getting it. It's hard to keep motivation sometimes.

(See more progress on "Be a better blogger"...)

Chuck it!

2004-12-15T20:06:00.000-08:00

I've never owned a TV (my parents having one doesn't count), and after getting married, I have much more intereting things to do than TV or video games.

Current hobbies:
Photography (esp. spherical panoramic)
Geocaching
Electronics (designing my own stuff)
listening to podcasts while commuting

Why would I want to waste time with a TV?

(See more progress on "live without a television for a year"...)

Moved to Seattle

2004-12-15T20:00:00.000-08:00

I took I-90 straight from Boston to Seattle, and WOW, what a trip. Did a couple quick detours (Badlands, Mt. Rushmore, Yellowstone) and skipped a few (Wall Drug) Made it 5 days with everything I own. Tip: if you do this in the summer, avoid the two weeks around Sturgis!

(See more progress on "Drive across the USA"...)

2 years next week

2004-12-15T19:55:00.000-08:00

Getting married is a great thing. Knowing that you get to see the same person every day, knowing that life is more stable with two people working, and having someone to help you get up in the morning.

Another great thing about marriage is sharing excitement with your spouse. If I design something cool (even if it only really blinks lights in a fancy way), my wife will be excited and ask me how it works. It's great.

(See more progress on "get married"...)

Test post

2004-12-15T19:47:00.000-08:00

I am doing 43 things.