Cheap and Easy Time Lapse Video (Intervalometry)

by depotdevoid in Circuits > Cameras

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Cheap and Easy Time Lapse Video (Intervalometry)

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Time lapse, also known as intervalometry (as in measuring intervals between photographs), is a method of taking pictures slowly over time and then compiling them into a video of compressed time.  I've always been fascinated with time lapse videos.  I remember when I was very young, seeing a time lapse video of a vine growing and creeping around at night.  I was amazed!  A good time lapse video can change your whole perspective and understanding of seemingly uninteresting everyday things.

I always assumed that making these videos would require specialized equipment that would be out of my price range.  Turns out, you can produce high quality time lapse videos with a very small investment, my own output was just $45 for a spare camera, though you may have to pay more or less depending on your situation.

I had purchased the equipment I needed a while back, but then let this project sit on the back burner.  When I was down at Maker Faire in spring 2011, I got to talking to mikeasaurus about the idea--he was working on his own time lapse videos involving a shoulder mounted webcam.  We talked about it and played with his rig, and we were originally going to make a collaborative project, but sadly his effort suffered from some technical difficulties and had to be shelved.

In the mean time, I returned to Oregon and started seriously working on my own time lapse stuff.  Take a look at the videos below, the first is all my best stuff up to about mid August of 2011, and the second is some longer term stuff I've worked on since then.  Read on if you'd like to learn how to make your own cheap and easy time lapse videos!

I highly recommend you make this full screen and full resolution to get the total effect:




Gather Materials

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For the videos, you will require:
  • A Canon brand digital camera that is compatible with CHDK (see step 2)
  • An SD card, the biggest compatible with your camera
  • An AC adapter for your camera (not required but very useful)
  • A computer with an SD card slot or an SD card reader and simple movie making software
I also built a simple water resistant case so I wouldn't have to worry about the constant Eugene rain, for something similar you'll need:
  • A waterproof tupperware (or whatever) container
  • A small piece of clear plastic
  • Hot glue
  • Silicone caulk

CHDK: Where the Magic Happens

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The secret to all of this is the Canon Hack Development Kit:  CHDK.

CHDK is an open source, alternative firmware for many Canon digital cameras.  Much like Rockbox or various ports of Linux, CHDK overrides the standard operating system of your camera, allowing for much greater user control.  Most Canon cameras, from the low end point and shoots all the way up to the high end DSLRs run on the same Digic processors, and contain much of the same internal hardware.  The functions of these processors are limited in the low end cameras by the native firmware, but their capabilities can be unlocked by the CHDK firmware.  

Specifically, CHDK allows you to create and run macros, or a series of commands that are set in motion and continue without requiring you to be there at all.  Rather than requiring an expensive high end camera or an analog intervalometer, CHDK allows you to set an interval for pictures, and it will continue taking them as long as it has power and space on the SD card.

Choosing the Right Camera

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This is very easy--just pay attention to Craigslist.  Find a Canon brand camera that is on this list (check the details of the specific camera to make sure it is fully compatible) and snap it up!

I ran a search on CL every couple of days for a few months until I found a camera that matched my specs.  I wanted to pay less than $50 for it, and I wanted it to be new enough that I could use it as a backup for my main camera.  I ended up with a Canon A570is, a model that's currently about six years old, but still takes high enough resolution photos to serve as backup for my other camera.

If I hadn't been picky about it, I could have had one the first week for about $20.  You don't need phenomenal resolution for time lapse, so don't get hung up on megapixels if all you want is a machine dedicated to this project.

*** Please note--a lot of older cameras can't read the larger SD cards available today.  Make sure you check the specs before you pick up a 32GB card, in case your camera can only do 4!

Installing CHDK

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Fair warning, I suspect this violates any warranty you might have on the camera!  It could also possibly brick your camera, but the impression I get from the CHDK site is that is extremely unusual.

Installing CHDK is very simple, and takes just four steps--you can see a comprehensive installation guide here, or just follow these directions.

1.  Find your camera's firmware version
Plug the SD card into your computer and create a plain text file on it called ver.req.  Make sure you've got the ability to see file extensions so that you don't end up with "ver.req.txt or something--on a PC you can turn this ability on in the folder options menu, I'm not sure how it's done on a Mac.  Remove the card and place it back in your camera.  Turn on the camera in playback mode and press the func.set and disp buttons at the same time (or the func.set and down buttons on some cameras).  You'll see something along the lines of "Firmware ver GM1.00E", it's the 1.00E or whatever that you need.  Write that down and move on to the next step.

2.  Install and run the CardTricks software
This program (again, this is for PC, I'm not sure how to do this on a Mac), both makes the SD card bootable and installs the proper version of CHDK on it.  Follow this link, download, install, and run.
  • Click "Format as Fat" (remember, this will delete everything on your SD card, so save any pictures first!)
  • Click "Make Bootable"
  • Click "Download CHDK" and choose your camera and firmware version, download and save the zip file
  • Click "CHDK ->Card" and choose the zip file you just downloaded
3.  Install the time lapse macro (known as a "Script" in CHDK)
In the CHDK/Scripts/ folder on the SD card, create a plain text document called "timelapse.bas" and put the text located here into that file, then save it.  This is the time lapse macro I use, and it's served me quite well so far.  Again, make sure the file name ends in .bas, not .txt.

4.  Eject the card from your computer, and install it in your camera
Make sure before you put it in the camera, you switch the lock tab on the card to the locked position!  From now on, if the card is locked, CHDK will load on your camera, and if it's unlocked, your standard Canon OS will load.



Finding a Good Subject for Time Lapse

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I've been playing around with this rig for the last several months.  I've had some successes, and some failures.  I've found a number of good subjects:
  • Clouds
  • Stars
  • Wide panoramas
  • Car trips
  • Plants growing
  • Flowers as they open and close
  • Fruit growing
  • Bugs of various sorts
  • Traffic
  • People/parties
  • The transition from day to night and night to day
I suspect having a small device to slowly pan the camera would enhance a lot of these effects as well.

One thing to take into account when choosing your subject is how much time you'll require to get a decent time lapse video.  For instance, when making a video of a car trip, you'll want to take pictures as fast as you can--usually about 1/second with this setup. However, when taking video of a plant growing, maybe one picture every five minutes over the course of a month might be required.  I found myself misjudging things a lot over the course of this project, and had to scrap more than one video.  Practice makes perfect, and trial and error is at the heart of this process!

A couple of problems I have found, but haven't been able to fix yet:
  • For anything lasting more than a day, artificial lighting is best.  The constant day/night shift is a bit difficult to deal with.  However, finding a dedicated area where the lights are always on and the curtains never opened is difficult.
  • Long term projects are sensitive to people interfering.  Apparently, a sign reading "DO NOT TOUCH!" isn't enough for some people, and one of my longest-term projects had to be totally scrapped.

Building a Simple Water Resistant Enclosure

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While definitely not a required step for everyone, I knew I'd be taking pictures outside in Eugene weather.  It rains here constantly, so I figured I'd better have a way to keep the camera outdoors without worrying about water damage.

I started with a good sized rubbermade food storage container and marked off where the camera sat inside of it when turned on.  Next, I drilled a hole in the opposite side and cut a section of the front off.  

I installed a piece of clear plexiglass in the hole I'd cut in the front and hot glued it in place.  I arranged it so that the camera, when turned one, would push the lens right up against the clear plastic.  Using silicone caulk inside and outside I sealed that off.

I pushed the power chord through the hole drilled in the back and then caulked that in place as well.  This setup worked out pretty well, allowing me to leave the camera outside for several days at a time without worrying about the weather.

Taking a Time Lapse Video

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Once you've found your subject, turn on your camera in picture mode.  I generally turn off the auto flash, as this often takes a while to recharge and annoys the neighbors if it's going all night.  Also, you can choose your base picture resolution at this point.

Next, hit the print/ALT button (generally up and to the right of the directional pad, and with a blue LED built into the button).  This activates the CHDK alternate buttons, allowing you to change parameters.  Hit menu, then select scripting parameters from the list.  Choose timelapse.bas, and change the timing parameters offered there.  

With the software you've already installed, you'll be able to set a delay before the first picture, and also force change the picture resolution.  Most importantly, you can choose the delay in between pictures, from tenths of a second to several minutes.

Once you've chosen the scripting parameters, hit the shutter button, leave your camera, and check back when you think it's going to be ready!

Compiling Your Video

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After the appropriate time has elapsed, gather up your camera, switch the SD card back to unlocked, and put it in your computer.  Pull the pictures off the card and delete them so you've got space to fill it up again!

Using simple video editing software like Windows Movie Maker, you'll be able to add the pictures to a video project, and then determine the duration of each picture.  I prefer using the version of Movie Maker included with Windows 7, it allows much finer control of the picture duration.  Generally, I take .05 seconds/picture as a default and then see if it needs to be slowed down or sped up.

Save the resulting video to your computer before making your final judgement--Movie Maker sometimes has difficulty showing the full frame rate before the whole video is processed.

Some Videos I've Made


Here are a few videos I've made with this process.

First, the "Best Of" videos from before:





Next, the very first video I made, India and I playing Uno:



Here is the first cloud video I made, about 5 hours worth of me working on a Saturday:



A day in my back yard:



This one is me taking a walk in the wetlands at lunch:



Here is the first video I considered good, make sure you go full screen and full res for this one:



Final Thoughts

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I really loved this project.  In fact, I'm still working on it!  I've been making videos fairly constantly since I returned from Maker Faire last year, and I'll continue to do so . . . as long as the camera lasts, that is.  After taking around 3-4 hundred thousand pictures, it seems the autofocus is starting to go out.  I may have to retire this camera soon, though I think I may be able to revive it for an astronomy project I've got in mind!

Thank you for reading!  Please take a minute to rate, comment, and subscribe, I live for feedback from my readers!

If you should use this project to make your own time lapse video, post it in the comments below, and I'll send you a digital patch and !