The Next Lizard Climate Control…

I’ve started on LCC 2nd Gen or LCC2 or LCC II. I don’t know what to call it. BUT I do know it’ll be killer.

This one is going to be everything LCC 1 was not.

So far I have:

  • Ethernet
  • 64 GPIOs
  • A better RTC
  • 2 OLED displays
  • The RTC can be updated via serial — no need to upload code to the Arduino, update the clock and then reupload the LCC code!
  • More cool factor….

So check this out- I2C rocks! The awesome Centipede Shield from macetech.com is HUGELY awesome. Via the I2C 2 wire interface you now have access to 64 Digital ports. In any combination of In or Out. This is the cornerstone of the new LCC hardware. Especially since the Ethernet takes a lot of digital ports. This thing is way cool. If you need more digital ports get one asap.

The OLED displays are really neat. I got 5 from a Kickstarter project and they’re now generally available from Sabernetics Tech. They’re tiny and bright! Since you now have 64 ports you can have as many of these displays as you want. Just put each on its own port to select which one to write to…If you don’t you’ll write to them all at once! Gotta love bus networks (I2C).

I hope to make the LCC’s ability to control lights and heat sources more generic. Since the IO is so plentiful I can make the code generic enough to handle fans, heat mats, uv lights etc in different combinations.

Keep checking the site as I post updates about this project!

Why are Camera Lenses Round and Film Square?

This is a thinking project. I’ve asked The Straight Dope and not heard back yet… I’m sure I know or can come close to the answer but lets talk it out and see where it goes.

For our purposes we need some definitions:

  • Square = Any object of square, rectangular, boxy or cube likeness. Corners are always 90 degrees.
  • Circle = Any object of circular, oval, spherical or generally round like shape, regardless of deformation on a planar axis (lens shape). Has no corners.
  • Clear = Any material that is optically clear; as in it allows the visible spectrum of light to pass through it.
  • Film = Any image receiving material. This could be old style polyesterPETnitrocellulose or cellulose acetate light sensitive film or new style electronic optical sensors like CCD and CMOS.

So why is a camera lens round and the film square? Why not round film? Why did it get setup like this?

Lenses

In order to focus and direct light the object or medium doing this has to be clear (duh!). This ability isn’t exclusive to round objects though. Windows are square. Windows are round. Some windows are both square and round. Same goes for eye wear. They’re all optically clear, but the shapes vary from square to round.

To focus light, the clear object needs to be distorted (convex or concave if you like). You can see this with old school eye wear.  Remember the coke bottle jokes? A cross section of the lens was more of a shallow bowl shape. Today this is less so, but the lens is definitely distorted.

Taking a closer look at a focusing lens though shows me something interesting- as you get towards the outer edges of the lens, its ability to keep the image in focus fades. Take a look at a magnifying glass. They’re usually convex on the outsides and the only part of the image in focus is what’s in the middle. The more it magnifies the more distorted the image is as you look farther from the center.

If we had film that was round, the outer edges would most likely be out of focus. BUT! If the film was smaller than the image cast by the lens the film would only capture what was in focus.

Makes sense. Right?

Film

Film is square. CCD (charged coupled devices) and CMOS devices are the electronic versions of film. But they’re still square. Why?

Well from an electronic perspective I can tell you that the matrix of dots that make up the CCD and CMOS chips makes sense. A matrix is square or cubic. Think of a spreadsheet. Each pixel in the matrix (cell) has an address. Spreadsheets have letters on the x and numbers on the y axis. CCD matricies are similar. The combination of x and y allow each pixel (cell) to be addresses individually. This makes sense. Old school chemically developed film doesn’t have to deal with this, but it did have to be coated evenly with the photo sensitive material. So why did they start out square?

Here’s my guess. Humans like square objects:

  • they stack perfectly
  • they are easy to handle
  • they store well
  • they organize well
  • straight lines seem to be easier to make and cut as opposed to arcs or circles
  • the written word has typically been on square like tablets
  • humans tend to read in lines- lines are straight (how hard would a book be to read if the text was along a circular path from outside in??)
  • paintings and drawings seem to lend themselves to square canvases
  • they’re not round

From a design and engineering perspective the square (or plate that is square) seems to make sense too. Engineers like to make machines use  round things for moving parts and square parts to hold the round ones. For example look inside a laser printer or any printer for that matter:

Laser printer mechanics

See all the round stuff? Guess what holds it in place? Big squares of metal or plastic. Maybe engineers and inventors have always thought this way. I can’t find an answer to that. I’d love to see another take on this.

So back to film. It’s square. Traditional film was a roll (really big rectangle or long square…) divided into frames. Really really old film was on plates. Square plates. One single square plate per frame. Present day “film” sensors are square. They output square images. Those images are made of square pixels. Square.

Printing or developing film has always been on paper. Paper is square. Printers (the machines, not the people) like square paper. Ever tried to use a round sheet of paper in a printer?

Mechanically it seems to make sense to use squares to print on.

The Conundrum

So we know that light focuses best through distorted round clear things. We know that humans, machines, math and computing devices like squares. I guess light will just have to be the odd one here. (I know math likes circles too, but squares seem to be easier to calculate. They have good symmetry (ok so do circles). Call me lazy.)

Lenses focus the light onto square film. But wait. The incoming image isn’t square. It’s round. Sadly, some of the image is lost. Happily, the lost parts of the image are the ones from the outer edges of the lens that are out of focus. Remember earlier:

Taking a closer look at a focusing lens though shows me something interesting- as you get towards the outer edges of the lens, its ability to keep the image in focus fades. Take a look at a magnifying glass. They’re usually convex on the outsides and the only part of the image in focus is what’s in the middle. The more it magnifies the more distorted the image is as you look farther from the center.

I guess I just answered my conundrum.

My Conclusion

Lenses are round because they focus light better than a square. Round lenses are most likely easier to manufacture than a square lens that is, well, rounded.

Film is square because it is easiest for humans and machines to manipulate. Paper has always been square. Printing has always been done on squares. Old film on plates was square because it was originally done on glass. Which was already square for windows (I assume….). Machines like squares.

Square film also conveniently solves the issue of round lenses distorting the outer parts of the image. The film is only exposed to the most focused center of the incoming light. Call it auto cropping. It seems as though cropping an image is just built into the design. Whether the cropping was intentional or not, it worked and it happened long before we had digital cropping tools.

 

Comments?  I’d love to hear them. Did I screw up something? Let me know!

 

 

 

 

LCC Breadboard Visual

Below is the breadboard circuit diagram. It’s pretty final. I hope to clean it up a bit when the project is final.

The major additions in this rev is that I’m using transistors against the Arduino digital outs to control the AC relays and a corresponding LED indicator.  The on/off switches in those circuits provide a bypass to turn on the AC switches if necessary.

Tri-Temp project

Coming soon- the mostly completed Tri-Temp box. Two editions- Standard and Ethernet. I’m still finishing it up and have lots of pictures.

  • Measure temperature and humidity from three locations via digital probes
  • Self contained in a small project box
  • Standard uses Arduino UNO
  • Ethernet uses Arduino Ethernet
  • Uses 16×2 LCD to display on Standard version
  • Ethernet uses LCD plus web interface!
  • LCD interfaces with Arduino via serial- no hogging all the digital lines!
  • It has its own logo!
  • Internal temp monitoring….just because
  • 3 wire External digital probes are pluggable and cheap!
  • Runs on 9v battery (don’t know how long yet….)
  • 4 interface buttons on project box to control the display

I should have it wrapped up and posted soon. The code will no doubt be a constant work in  progress but the hardware is almost complete.