Intervalometer

I previously promised to show how I made the time-lapse video of me installing an IKEA floor, so I figured it was time for me to keep my promise.

An intervalometer is basically a device that keeps track of intervals of time, just like a speedometer keeps track of speed and a thermometer keeps track of temperature. When an intervalometer is attached to a camera, it allows the camera to take a picture regularly at a set interval of time. If, for example, I attached an intervalometer to a camera and set it for twenty seconds, the camera would take a picture every twenty seconds.

“How is this useful?” you might ask. Well, time-lapse videos are made up of series of photographs that were taken regularly over a long period of time and then played back quickly so that something appears to happen much faster than it normally would. This allows you to watch me install the IKEA floor in a few seconds rather than a few days.

The only problem is that intervalometers are usually expensive, and if you don’t plan on making lots of time-lapse videos, it doesn’t really make sense to buy one. However, using a little creativity (that I leeched off someone on Instructables) and a bit of resourcefulness, I was able to put one together with a few things that I already owned or had access to.

The idea was to take the trusty TI-83+ graphing calculator that my parents bought for me in high school (That calculator was a good investment; I still use it to this day!), write a little program to allow it to keep track of intervals, and connect it to the Canon Rebel XT that I borrowed from my aunt.

If you’ve ever looked at the bottom of a TI graphing calculator, there is a little opening that looks like a headphone jack. It’s actually a data port that is used to connect graphing calculators together to allow them to exchange information. If you’ve ever looked at the side of a DSLR (like the Canon Rebel XT I just mentioned), you’ll notice another opening that looks exactly like the one on the TI graphing calculator. The difference is that this jack is used to connect a wired remote to the camera to allow you to take pictures without touching the camera. All that this remote has to do is send a little electrical signal (any electrical signal; it’s not picky) and the camera will snap a picture. Usually, that’s accomplished by pressing a button on the remote, but instead of a remote, I used my graphing calculator.

Sparing the details, I typed in the following program written in TI-BASIC into my calculator:

PROGRAM:CAMERA
:Prompt A
:While 1
:For(H,1,A,1)
:End
:Send(A)
:End

What this program basically does is ask you to input a number, A, which denotes the amount of “time” you want to pass before it sends the signal to the camera to take the picture. After this amount of “time” elapses, the program will output an electrical signal through to the camera causing the camera to snap a picture, and then it will restart the timer and continue counting until it reaches the value of A again. This loop continues until you interrupt it by pressing the ON key on the calculator.

The result of running this program is a series of photographs stored on the camera that you can stitch together to form a time-lapse video. (In HD nonetheless!) QuickTime has a useful little function called “Open Image Sequence…” (found in the File… menu) that I used to accomplish this task once I imported all the pictures into my computer. This produced a very, very large video that I downsized and compressed to give the final result.

You can see a couple of blurry pictures of my setup in the gallery below.

4 Comments

  1. Christine · May 28, 2009

    That’s pretty amazing. You’ve had this blog for a while! Thanks for helping me out today, 6th period was a mess and I’ve vowed never to sub for Garcia again. It was good seeing you though, keep me posted!

    Reply
    • Hiram · June 1, 2009

      Hi! Thanks for reading this! (: I’m glad I was able to help, though I’m sorry Garcia’s class turned out to be horrible. I promised myself the same thing the last time I subbed for him. It was good seeing you too, even if in the most hectic of circumstances. (:

      Reply
  2. Andreas · February 8, 2010

    So is there a way to make a similar program with BASIC language?

    Reply
    • Hiram · February 8, 2010

      I’m not exactly sure what differences there are between BASIC and TI-BASIC, but they most likely have to do with input/output. I would imagine a similar BASIC program would look exactly the same except for Prompt A and Send(A). The Prompt command just asks for user input and stores that input into a variable. The Send command outputs whatever is passed into it to a mini-jack on the bottom of the calculator. So, depending on what you’re trying to accomplish, you would have to find the appropriate functions in the BASIC language. I hope this helps!

      Reply

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