Author Archives: bob

Jumps 26-28

Posted by bob in Skydiving | Sports - (Comments Off)

It’s been three years since I’ve been skydiving. Once Richland Skysports closed, I no longer had a local place to dive. It took the desire of a coworker to jump to motivate me to get back into it. I went the weekend before she was supposed to go so that I could take care of all the things I needed to to be able to jump with her the next weekend. After talking to the instructors and getting a refresher quiz, they let me do a hop and pop, jumping at 7000 and freefalling for ten seconds before pulling. It wasn’t the cleanest exit, but I didn’t hesitate to do it. I had no problem jumping out, but I didn’t have the best posture and struggled for a few seconds to get right. It happened quickly enough, though. I had no problem pulling my chute, and was happy playing around under canopy. I was a little high on the approach but still landed on the grass a very happy guy. They showed me a photo of me exiting the plane, and it was very embarrassing how bad my body position was on exit. It was no wonder I struggled on the first jump.

That was enough to satisfy the instructors, though, and they let me jump at 12500 for my next jump. I was excited to practice freefalling, and took the opportunity to do flips forward and backward, a barrel roll, turning, and some tracking. I had good altitude awareness and didn’t have any problem pulling at the right altitude. I landed on the grass again.

I had some help packing my own chute this time, and got back on the plane for the next ride. This time I played around some more with flips, adjusting my fall rate, tracking, and heading control. I had no problem with my opening. The wind changed, and the landing pattern was different; we were going left handed turns, which brought us over the top of the building. I was a little nervous about that and ended up going over the building a little high and overshooting the grass by a few feet. I landed on the dirt and slid to a stop.

There weren’t going to be any more loads, so I paid and came home, ultimately very satisfied with my day. Read my style=”text-decoration: none” href=”http://yourellipticals.com/proform-elliptical-reviews/”>ProForm Elliptical Reviews 2016 and let me know your thoughts on it.

Trying something new

Posted by bob in Uncategorized - (Comments Off)

It’s been over a year since I’ve posted, which is not cool. I’d like to say it was the fault of the technology I was using, and that it was a hurdle, but that’s just making excuses. A lot has happened in the last year. The girlfriend and I have traveled to Vietnam, Thailand, Vancouver, Belize, Guatemala, Seattle, Montana, and a bunch of other places. Work hasn’t been much different, but it’s always interesting. In fact, a lot has happened, but over the course of a year, it condenses quickly into only a couple sentences. This is no longer acceptable, so I’ve decided to change technologies, and devote more time to posting about the things that I do. We’ll see if it works out well.

What I Read

Posted by bob in Uncategorized - (Comments Off)

I’ve been doing a lot of interviews at work lately, and one of the questions I like to ask is what they read to keep current. In my job I am constantly evaluating new technologies and incorporating new things into our work, and it’s essential that I stay up to date with the latest in news, software development practices, gadgets, and just the field in general. I can’t count how many times I’ve seen something in my daily reading and used it in my work or at home. I rarely comment or contribute to the sites; I prefer just to watch and not participate in what’s usually a flame war by people with questionable qualifications. I read some of the sites at work, but most at home after work.

So here is my list of things I read daily in the industry:

  • http://slashdot.org – I’ve been reading this for 10 years and have only commented a few times, but I check this many times a day and have used information I’ve found on this site for all kinds of things.
  • http://news.yahoo.com – I read this a few times a day to keep up with the news in general. I’ve found this site is the best news aggregation site of the ones I’ve tried.
  • http://finance.google.com – I use this to track a few stocks and look at relevant business news and new pay day loans opportunity’s.
  • http://digg.com – I usually do this from home as it has interesting stuff in all kinds of categories.
  • http://gizmodo.com – This site is useful for the latest in gadget and technology news.
  • http://engadget.com – Almost identical to Gizmodo, and they often report on the same things, but sometimes they have a different interpretation.
  • http://joelonsoftware.com – Joel Spolsky’s blog. Somewhat diluted with his own advertising for his talks and conferences, but often has good articles on managing a tech company.
  • http://www.reddit.com/r/joel/ – This channel of reddit is for articles similar to the ones Joel writes.
  • http://thedailywtf.com/ – Every day an article or two about some curious piece of code or business practice.
  • http://www.lifehacker.com – Nifty tools and tricks for technology and geek life.
  • http://fark.com – Mostly curious or silly news, this is great for keeping up with the strange stories that are likely to come up in conversations.

That’s every day, sometimes a few times during the day. I’d say I spend about 2 hours reading stuff each day, though only about 1/2 an hour to an hour of that is at work, and usually in a few spare moments while I’m in between meetings or tasks.

This list does a pretty good job of keeping me up to date in the world.

Laser Pointer Interface

Posted by bob in Computers - (Comments Off)

A while ago I built a computer input device using a laser pointer and regular usb web camera.

It was a pretty simple setup, and I used a lot of existing tools as a jumping off point. Here’s a writeup of my work and details for how to replicate it and what I learned.

First, a video overview:

Materials

At a minimum:

  • A web camera
  • A laser pointer

Optionally:

  • A projector

Technically speaking, the laser is completely optional. In fact, during testing I just had a desktop computer with the camera pointed at a sheet of paper taped to a wall, and I drew with the laser pointer on that sheet of paper and used that as an input device. With the projector, you can turn the setup into a more direct input, as your point translates directly to a point on a screen. But that’s just a bonus. This can be done without the projector.

Physical Setup

Take the camera, point it at something. Shine the laser inside the area where the camera can see. That’s it in a nutshell. However, there are some additional considerations.

First, the more direct the camera, the more accurate it will be. If the camera is off to the side, it will see a skewed wall, and because one side is closer than the other, it’s impossible to focus perfectly, and one side of the wall will be more precise than the far side of the wall. Having the camera point as directly as possible at the surface is the best option.

Second, the distance to the surface matters. A camera that is too far from the surface may not be able to see a really small laser point. A camera that is too close will see a very large laser point and will not have great resolution. It’s a tradeoff, and you just have to experiment to find the best distance.

Third, if using a projector, the camera should be able to see slightly more than the projected area. A border of a few inches up to a foot is preferable, as this space can actually be used for input even if it’s not in the projected space.

Fourth, it’s important to control light levels. If there are sources of light in the view of the camera, such as a lamp or window, then it is very likely the algorithm will see those points as above the threshold, and will try to consider them part of the laser pointer (remember white light is made up of red, green, and blue, so it will still be above the red threshold). Also, if using a projector, the laser pointer has to be brighter than the brightest the projector can get, and the threshold has to be set so that the projector itself isn’t bright enough to go over the threshold. And the ambient light in the room can’t be so bright that the threshold has to be really high and thus the laser pointer isn’t recognized. Again, there are a lot of tradeoffs with the light levels in a room.

Software Packages

I wrote my software in Java. There are two libraries that I depended on heavily:

The JAI library is not entirely essential, as you could decide not to translate your coordinates, or you could perform your affine transform math to do it and eschew the large library that will go mostly unused. The neat thing about this transform, though, is that it allows for the camera to be anywhere, and as long as it can see the desired area, it will take care of transforming to the correct coordinates. This is very convenient.

The JMF library exists for Windows, Linux, and Mac. I was able to get it working in Windows, but wasn’t able to get it completely working in Linux (Ubuntu Jaunty as of this writing), and I don’t have a Mac to test on.I hope i can get an ipage host soon and then i can test for all of them.

Basic Theory

The basic theory behind the project is the following; a laser pointer shines on a surface. The web camera is looking at that surface. Software running on a computer is analyzing each frame of that camera image and looking for the laser pointer. Once it finds that pointer, it converts the camera coordinates of that point into screen coordinates and fires an event to any piece of software that is listening. That listening software can then do something with that event. The simplest example is a mouse emulator, which merely moves the mouse to the correct coordinates based on the location of the laser.

Implementation Theory

To implement this, I have the JMF library looking at each frame. I used this frameaccess.java example code as a starting point. When looking at each frame, I only look at the 320×240 frame, and specifically only at the red value. Each pixel has a value for red, green, and blue, but since this is a red laser I’m looking at, I don’t really care about anything but red. I traverse the entire frame and create a list of any pixels above a certain threshold value. These are the brightest pixels in the frame and very likely a laser pointer. Then I average the locations of these points and come up with a single number. This is very important, and I’ll describe some of the effects that this has later. I take this point and perform the affine transform to convert it to screen coordinates. Then I have certain events that get fired depending on some specific things:

  • Laser On: the laser is now visible but wasn’t before.
  • Laser Off: the laser is no longer visible.
  • Laser Stable: the laser is on but hasn’t moved.
  • Laser Moved: the laser has changed location.
  • Laser Entered Space: the laser has entered the coordinate space (I’ll explain this later)
  • Laser Exited Space: the laser is still visible, but it no longer maps inside the coordinate space.

For most of these events, the raw camera coordinates and the transformed coordinates are passed to the listeners. The listeners then do whatever they want with this information.

Calibration

Calibration is really only necessary if you are using the coordinate transforms. Essentially, the calibration process consists of identifying four points and mapping camera coordinates to the other coordinates. I wrote a small application that shows a blank screen and prompts the user to put the laser point at each of the prompted circles, giving the system a mapping at known locations. This writes the data to a configuration file which is used by all other applications. As long as the camera and projector don’t move, calibration does not need to be done again.

Here is a video of the calibration process.

The Code

Here is the camera.zip (3.7mb). It includes the JAI library, the base laser application, the calibrator, and an example application that just acts as a mouse emulator.

Below are a couple snippets of the important stuff.

This first part is the code used to parse each frame and find the laser point, then fire the appropriate events.

/**
* Callback to access individual video frames. This is where almost all of the work is done.
*/
void accessFrame(Buffer frame) {
/***************************************************************************************/
/********************************Begin Laser Detection Code*****************************/
/***************************************************************************************/
// Go through all the points and set them to an impossible number
for (int i = 0;i<points.length;i++){
points[i].x = -1;
points[i].y = -1;
}
int inc = 0; //set our incrementer to 0
byte[] data = (byte[])frame.getData(); //grab the frame data
for (int i = 0;i<data.length;i+=3){//go through the whole buffer (jumping by three because we only want the red out of the RGB
//if(unsignedByteToInt(data[i+2])>THRESHOLD && unsignedByteToInt(data[i+1])<LOWERTHRESHOLD && unsignedByteToInt(data[i+0])<LOWERTHRESHOLD && inc<points.length){//if we are above the threshold and our incrementer is below the maximum number of points
if(unsignedByteToInt(data[i+2])>THRESHOLD && inc<points.length){//if we are above the threshold and our incrementer is below the maximum number of points
points[inc].x = (i%(3*CAMERASIZEX))/3; //set the x value to that coordinate
points[inc].y = i/(3*CAMERASIZEX); //set the y value to the right line
inc++;
}
}
//calculate the average of the points we found
ave.x = 0;
ave.y = 0;
for (int i=0;i<inc;i++){
if (points[i].x!=-1){
ave.x+=points[i].x;
}
if (points[i].y!=-1){
ave.y+=points[i].y;
}
//System.out.println(points[i].x + "," + points[i].y);
}
//System.out.println("-------------------");
if (inc>3){//if we found enough points that we probably have a laser pointer on the screen
ave.x/=inc;//finish calculating the average
ave.y/=inc;
PerspectiveTransform mytransform = PerspectiveTransform.getQuadToQuad(mapping[0].getX(), mapping[0].getY(),
mapping[1].getX(), mapping[1].getY(), mapping[2].getX(), mapping[2].getY(), mapping[3].getX(), mapping[3].getY(),
correct[0].getX(), correct[0].getY(), correct[1].getX(), correct[1].getY(), correct[2].getX(), correct[2].getY(), correct[3].getX(), correct[3].getY());
Point2D result = mytransform.transform(new Point(ave.x,ave.y),null);
in_space = !(result.getX()<0 || result.getY() < 0 || result.getX() > SCREENSIZEX || result.getY() > SCREENSIZEY);
if (!on){
fireLaserOn(new LaserEvent(result, new Point(ave.x, ave.y), last_point, last_raw_point,in_space));
on = true;
}
if (in_space && !last_in_space){
fireLaserEntered(new LaserEvent(result, new Point(ave.x, ave.y), last_point, last_raw_point,true));
}
//                System.out.println(result.getX() + "," + result.getY());
//                System.out.println(last_point.getX() + "," + last_point.getY());
//                System.out.println("----------------------");
if (result.getX()!=last_point.getX() || result.getY()!=last_point.getY()){
fireLaserMoved(new LaserEvent(result, new Point(ave.x, ave.y), last_point, last_raw_point,in_space));
}
else{
fireLaserStable(new LaserEvent(result, new Point(ave.x, ave.y), last_point, last_raw_point,in_space));
}
if (!in_space && last_in_space){
fireLaserExited(new LaserEvent(result, new Point(ave.x, ave.y), last_point, last_raw_point,false));
}
last_time = 0;
last_point = new Point2D.Double(result.getX(), result.getY());
}
else if (last_time==5){//if it's been five frames since we last saw the pointer, then it must have disappeared
if (in_space){
fireLaserExited(new LaserEvent(-1,-1, ave.x, ave.y, (int)last_point.getX(), (int)last_point.getY(), (int)last_raw_point.getX(), (int)last_raw_point.getY(),in_space));
}
fireLaserOff(new LaserEvent(-1,-1, ave.x, ave.y, (int)last_point.getX(), (int)last_point.getY(), (int)last_raw_point.getX(), (int)last_raw_point.getY(),in_space));
on = false;
in_space = false;
}
if (ave.x>0 || ave.y>0 && ave.x<CAMERASIZEX && ave.y<CAMERASIZEY)
fireLaserRaw(new LaserEvent(-1,-1, ave.x, ave.y, -1,-1, (int)last_raw_point.getX(), (int)last_raw_point.getY(),in_space));
last_time++;//increment the last_time. usually it gets set to 0 every frame if the laser is there
last_raw_point = new Point(ave.x,ave.y);//set the last_point no matter what
last_in_space = in_space;
/**************************************************************************************/
/********************************End Laser Detection Code*****************************/
/*************************************************************************************/
}
public int unsignedByteToInt(byte b) {
return (int) b & 0xFF;
}

This next part is pretty standard code for adding event listeners. You can see which laser events are getting passed. I intentionally made it similar to how mouse listeners are used.

Vector<LaserListener> laserListeners = new Vector<LaserListener>();
public void addLaserListener(LaserListener l){
laserListeners.add(l);
}
public void removeLaserListener(LaserListener l){
laserListeners.remove(l);
}
private void fireLaserOn(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserOn(e);
}
}
private void fireLaserOff(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserOff(e);
}
}
private void fireLaserMoved(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserMoved(e);
}
}
private void fireLaserStable(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserStable(e);
}
}
private void fireLaserEntered(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserEntered(e);
}
}
private void fireLaserExited(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserExited(e);
}
}
private void fireLaserRaw(LaserEvent e){
Enumeration<LaserListener> en = laserListeners.elements();
while(en.hasMoreElements()){
LaserListener l = (LaserListener)en.nextElement();
l.laserRaw(e);
}
}
  • This algorithm is extremely basic and not robust at all. By just averaging the points above the threshold, I don’t take into consideration if there are multiple lasers on the screen. I also don’t filter out errant pixels that are above the threshold by accident, and I don’t filter out light sources that aren’t moving. A more robust algorithm would do a better job and possibly identify multiple laser pointers.
  • I’m not the first person that has done this, though from what I can tell this is the first post that goes into so much detail and provides code. I have seen other people do this using other platforms, and I have seen other people try to sell this sort of thing. In fact, this post is sort of a response to some people who think they can get away with charging thousands of dollars for something that amounts to a few lines of code and less than $40 in hardware.
  • Something I’d like to see in the future is a projector with a built in camera that is capable of doing this sort of thing natively, perhaps even using the same lens system so that calibration would be moot.
  • You may have seen references to it in this post already, but one thing I mention is having the camera see outside the projected area and how that can be used for additional input. Because the laser pointer doesn’t have buttons, its input abilities are limited. One way to get around this is to take advantage of the space outside the projected area. For example, you could have the laser act as a mouse while inside the projector area, but if the laser moves up and down the side next to the projected area it could act as a scroll wheel. In a simple paint application, I had the space above and below the area change the brush color, and the sides changed the brush thickness or changed input modes. This turns out to be extremely useful as a way of adding interactivity to the system without requiring new hardware or covering up the projected area. As far as I can tell, I haven’t seen anyone else do this.
  • I have seen laser pointers with buttons that go forward and backward in a slideshow and have a dongle that plugs into the computer. These are much more expensive than generic laser pointers but could be reused to make the laser pointer much more useful.
  • Just like a new mouse takes practice, the laser pointer takes a lot of practice. Not just smooth and accurate movement, but turning it on and off where you want to. Typically releasing the power button on the laser pointer will cause the point to move a slight amount, so if you’re trying to release the laser over a small button, that has to be considered so that the laser pointer goes off while over the right spot.
  • This was a cool project. It took some time to get everything working, and I’m throwing it out there. Please don’t use this as a school project without adding to it. I’ve had people ask me to give them my source code so they could just use it and not do anything on their own. That’s weak and you won’t learn anything, and professors are just as good at searching the web.
  • If you do use this, please send me a note at laser@bobbaddeley.com. It’s always neat to see other people using my stuff.
  • If you plan to sell this, naturally I’d like a cut. Kharma behooves you to contact me to work something out, but one of the reasons I put this out there is I don’t think it has a lot of commercial promise. There are already people trying to, and there are also people like me putting out open source applications.
  • If you try to patent any of the concepts described in this post, I will put up a fight. I have youtube videos, code, and witnesses dating back a few years, and there is plenty of prior art from other people as well.

Broken Car Lock

Posted by bob in Building - (Comments Off)

It’s no secret that I love my car. It’s been extremely dependable, has treated me very well, has a good personality and an adventurous attitude, and doesn’t ask for much (it’s a 2000 Chrysler Neon, and yes, I mean Chrysler). I’ve had it for almost 10 years and put over 100,000 miles on it myself in addition to the 20,000 that were on it when I got it used. If I were to get another car, I’d look for something exactly like the one I have.

But once in a great while it will have small issues. Once a wiring harness broke loose and cause the rear lights to go out. Other than that, it’s worked very well and could probably go for another hundred thousand miles without problem.

About a week ago I put my key in the door to unlock it and found that it turned freely. I had to unlock the passenger side and then unlock the driver side from the inside. For a few days I drove around without locking the door. Monday I finally got an opportunity to examine the problem. I was able to disassemble the door relatively easily. It was fairly straightforward except for the part where the window handle was connected, but I managed to find the service manual online and pop the handle off. Then I could get in to the Romford Locks mechanism and see where the problem was. It didn’t take long to discover the problem. The rod that connects the lock mechanism to the key had slipped off. The piece that held it on was missing. Figuring it was probably at the bottom of the door frame, I felt around and identified it. Yep, there was the problem.

That piece should be symmetrical. The piece that had broken was about 2 millimeters wide and because of that the thing slipped off the lock and was no longer holding the rod in place. It didn’t take much jostling for the rod to fall out.

I didn’t have any parts exactly like that, and I was up to the challenge of fixing it with parts that I had around the house. I made a crude washer out of a piece of scrap tin from a can. Then I made a springy curl of stiff wire that would take the place of the part that broke. I installed onto the lock mechanism and played with it a little to make sure it was stuck pretty well. I tried to take it off to adjust it a little, but couldn’t even get it off without some serious effort, so I just left it on there. I tested it thoroughly before putting the door back together. With the door completely reassembled, I tested it out some more, and it worked exactly like it had originally worked.

I’m kind of glad that my car is mostly mechanical and doesn’t have a lot of electronic parts. Electronic locks or windows would have made this a much more difficult operation. I’m also happy that I was able to build the parts that I needed from scratch and basic tools. Plus, I always enjoy doing things with my hands and seeing the results and saving money in the process.

Partially Failed Cheesecake

Posted by bob in Cooking - (Comments Off)

Saturday I had a party for work, so I thought I’d throw together a cheesecake. I used the recipe I’ve used a few times in the past. Better Homes and Garden, by the way. Rather than melt some semi-sweet chocolate, I went instead with a bottle of Hershey chocolate sauce. I was getting to the bottom of the bottle, and I noticed that as I squeezed it would spatter out in neat randomness. So on top of the swirled cheesecake filling I sprayed the sauce, not realizing that it would ultimately be the cause of a huge problem.

The cake cooked fine, and after I took it out of the oven it still looked good, but the spots where there was sauce looked a little weak and were starting to crack. When the top of a cheesecake begins to crack, the cracks turn to crevasses as it cools down, and that’s exactly what happened. There were three pretty big cracks as it cooled. I looked around for something to fix it and found a block of milk chocolate that Erin had given me. I thought I’d shave chocolate onto the top to see if it would cover up the cracks. But the chocolate shavings weren’t as silky smooth as I thought, and they broke up into smaller pieces than I expected. It was time to go to the party, so I made the decision not to bring the cheesecake. That turned out to be ok, though, because there was already a lot of food there.

Aesthetically, the cheesecake was mediocre. It tasted great, though. Here’s a picture, but remember, it only looks average; it’s too bad I can’t make the web lick-able.

Seeing with closed eyes

Posted by bob in Uncategorized - (Comments Off)

I’ve been working on my laser pointer recently, and in the course of my work I made an interesting biological discovery. Laser pointers are ridiculously bright. You can shine them on a finger and they’ll light up the finger so that you can see it from the other side.

You’re not supposed to shine lasers directly into the eye because they are so bright. Most laser pointers, though, are class 3 or lower, meaning they won’t do permanent damage if exposed briefly. Still, my eyes are not something I like to risk, so I don’t shine it into my eye intentionally.

However, in the course of fiddling with the pointer while waiting for a process, I held it against my temple, turned it on absentmindedly, and saw some red. At first I thought that the laser must be reflecting off of something and getting into my eye somehow, but it didn’t make any sense. It was a blurry red light and was clearly more intense closer to my temple. The light wasn’t escaping outside and reflecting off anything, either, because the laser was directly against my temple. I concluded that the light was actually traveling through my temple and into my eyeball and hitting my retina without going through my iris.

This is not a huge discovery. In fact, you can simulate the effect quite easily with nothing but a bright environment. Close your eyes. Then put your hands in front of your eyes. It gets even darker. With just your eyes closed, light is still passing through the lids and into the eye. With the temple, it just takes more light to get through to the retina.

I’m not too concerned about losing my eyesight from doing this, but I’m not going to keep doing it. It’s interesting that I can see things without having it go through the front of my eye.

Camera Troubles

Posted by bob in Building - (Comments Off)

Erin handed me a camera a week ago that had gone through some tough times. It had been dropped while on, and the lens assembly was broken and askew. The camera couldn’t recover from it on its own, and so I was brought in to see if I could fix it. Having been able to revive Erin’s camera, which had the misfortune of a drop into sand, and having removed dust from my own camera many times, I took on the job. Since it was already broken, the owner of the camera didn’t have any expectations of getting it back anyway, so it was a riskless job. The first image is of the camera, though the lens problem is not visible.

Taking the camera apart was not difficult. There were lots of tiny screws, but for the most part the pieces separated fairly easily. Of course, as I did it I learned little bits about the assembly that made taking it apart easier. The second picture shows the partially disassembled camera. The lens assembly came out without any screws.

The lens assembly out, I was able to partially disassemble it as well. There were two main lenses. The first was the big one in the picture below. The second was the small one in the picture below that. Both were capable of moving.

In fact, it was the plastic on the smaller lens that had broken, and was sticking out, preventing the lens assembly from closing back up. This little piece of plastic, which is the part closest to the camera, turned out to be extremely important. I tried at first to just remove it and reassemble the camera, but it turned out that it wouldn’t focus without it. The piece was essential for guiding the lens forward and back and without it a small spring was pulling it in a direction it shouldn’t have gone. I was able to super glue it back together, but then had to take a small file to remove small jutting slivers that were adding too much friction to the assembly. The hardest part was putting the whole lens assembly together and back apart over and over, which took many minutes each time, and put wear and tear on some components that were only ever meant to be assembled once. In fact, a great deal of time was spent maintaining and guiding parts back together, and resetting springs that had to be unset.

I thought that I had been successful and had fixed the camera, but there was a problem. When I took a photo, the iris would stay closed, and it wasn’t until I would dismantle the whole thing that I could reopen the iris. Clearly this would not work in the field. I had to dismantle the assembly further to discover another unfortunate break.

The iris is controlled by two extremely small electromagnets, which apply torque to two magnets, which have small arms at the end of them. Those arms push and pull the thin pieces of plastic over the lens to adjust the light levels. Unfortunately, one of the arms was broken on the small magnet.

This was the deal breaker. Without the arm, the iris wouldn’t function properly, and the images would be overexposed (or possibly underexposed). The magnet wouldn’t take to super glue, and even the process of gluing was made more difficult by the fact that all my tools were metallic and would move the magnets as soon as they got near. For a sense of scale, the pic below is of an object that’s 4mm long at its longest

It took a lot of time to work on the camera and figure out how it all fit together. There were a lot of little pieces that had to be assembled just so, and it’s such a shame that the camera is perfectly good except for a few misplaced atoms, and because I won’t be able to find a replacement will now likely be discarded in its entirety.

The Subtle Mechanics of Popcorn Poppers

Posted by bob in Uncategorized - (Comments Off)

In my old apartment I didn’t have a popcorn maker. I would put some vegetable oil in a sauce pan, pour a layer of popcorn kernels in, cover it, and heat it until the popcorn was ready. I didn’t have an electric one. Now that I’ve moved in to the new place, Erin has the electric variety, so I’ve been using that. I was making popcorn this evening and thinking about the popcorn popper and how it worked, and specifically how kernels can remain unpopped.

By observation, at the beginning of the popping a kernel at the bottom will pop up, sending the kernels above it flying, and often out of the popper. This is a huge loss of kernels for no good reason. They’re perfectly fine kernels that were prematurely propelled out of the popper. As the popping intensifies, the popped corn doesn’t all escape out of the cylinder and into the bowl, forming a sort of protective layer to keep unpopped kernels from shooting out of the cylinder. The steady current of hot air elevates this layer and at times it looses cohesion and the layer breaks down and all escapes the cylinder into the bowl, allowing unpopped corn to escape again. It’s a delicate balance.

In order to preserve as many kernels as possible, I’ve played around with some tools. Initially I tried a spoon. By holding the spoon inside the chute and over the cylinder I could partially block the exit of the cylinder. A couple kernels still escape, but because I prevent the popped corn from leaving, the protective layer builds up faster. Further, I can control the flow of popcorn out of the chute, ensuring that the protective layer remains without breaking down early. The only catch was that the spoon was too short and the hot air was heating up the whole metal spoon and by the end burning my fingers.

I could use a large wooden spoon from now on. That would cover up more of the cylinder and eliminate the heat problem but could introduce a congestion problem if it gets in the way and clogs up the chute and doesn’t allow me the fine control of the protective layer.

A better design of the popper might have been a taller and slightly inverted funnel cylinder. Both the tallness and the funnel shape would make it more difficult for stray kernels to escape while also facilitating a sound protective layer and retaining the heat inside for longer.

The final adjustment that could be made to retrofit existing popcorn poppers would be to the clear plastic piece that fits over the popper. With the installation of an adjustable gate, you could cover the opening to the chute entirely, ensuring no kernels escaped and retaining the heat inside the popper for longer. As the popping progresses, the gate could be opened by varying levels to allow the protective layer to remain as popped corn passed through the gate.

But I’m probably overthinking this. The spoon will work for now.

My Empty Cupboards Project

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For about a month leading up to my move, I stopped shopping for food. I was trying to clean out the cupboards and start over fresh. It was surprisingly easy. For a long time I was fine with meat from the fridge or freezer, for a few weeks I had fresh vegetables, and I had plenty of snackish food for between meals.

During the week or so that I moved my stuff, I had a hard time finding the motivation or the time or even the utensils to take care of too many meals, so I had fast food a couple days and pizza or sushi from Safeway a couple days.

Now I’m in the new apartment, and the project continues. I haven’t filled the cupboards yet. With the exception of a single cupboard that has baking stuff like sugar, flour, baking soda, etc., ALL of the food is in the fridge or on the counter. Having it on the counter has given me incentive to eat it, as it’s in my face and in my way. But it’s been about three weeks since I’ve moved and I’m still working away at the pile. In fact, I think I could continue this experiment for about another two weeks and still be ok.

A while ago I ran out of milk and eggs, and that had a huge impact on what I could do. Without those basic ingredients, a lot of the food became impossible. I couldn’t make bread or bake or do any kinds of desserts. A few days ago I broke down and got just milk and eggs, and that’s helped me along quite a bit.

Some of the things I’ve been making have been… interesting. There was an omelet made with mizithra cheese and diced prunes (it was actually pretty good), homemade tortillas with beans and salsa, beer bread with tuna salad, and other dishes. One of my favorite discoveries was that raw Ramen is an excellent substitute for rice cakes. Just open the bag, split the Ramen in half flat-ways (it’s easy to do), and spread jelly or peanut butter on it.

I’ve been craving a lot of meat, though, lately. I’d love to tear into a hamburger or a steak. And some of the food that I have left is more of a side dish, not a main course. I think I may break down and get some meat or vegetables so I can have the side dishes in a decent meal.

Another of my discoveries in this endeavor has been the strangeness of expiration dates. Perhaps it’s because of the dry and mold-free climate of this area, but I’ve been eating food that’s expired sometimes years ago. According to www.restorationusa.com – you’re not really supposed to keep your stored goods in moldy/damp areas, ie. basements and such, but I had corn tortillas that expired in February of 2008, and they were still perfectly fine. They were a little dried out at the bottom of the bag, but I sliced them up and baked them to make chips. I haven’t really come across much that I felt uncomfortable about eating, and some of it was canned food over a year past it’s date. I think either we shouldn’t be so prudish about expiration dates on food, or we should be using a lot less preservatives.

Yet another realization was that food just seems to accumulate in the cupboards, and sometimes just never gets consumed. There’s no good reason for it, just entropy. I have a can of jellied cranberries that is a few Thanksgivings old, and I just haven’t done anything with it. I could easily have it as a side dish with pork chops, but instead other foods have a much higher turnover in my kitchen. I need to be better about keeping the cupboards tight. The good news, though, is that the average family could probably survive a lot longer than they think if they had to.

The experiment will continue until all the food is gone. Then we’ll go shopping and stock the cupboards more wisely. As I scrape the bottom of the barrel in the coming days, I’ll probably buy one or two things to supplement the meals, but this has been an interesting and difficult challenge.