Knex Time-lapse intervalometer

Step 5 Gear Ratios

The default shot interval is 10 seconds. The rig can be very easily changed to give a 5 or 2 second interval. Before I show how to do this, Im going to explain which one you should use to begin with.

The timelapse is played back at 30 frames per second. In other words, if you take 30 shots with this rig it will give you one second of smooth video.

• Using the 10 second interval, that will take 10x30=300 seconds, or 5 minutes. So, for every 5 minutes that you leave the rig running, you get 1 second of video.
• Using the 5 second interval, you get 5x30=150 seconds, or 2 and a half minutes needed to get 1 second of video.
• Using the 2 second interval, you get 2x30=60 seconds, or 1 minute needed to get 1 second of video.

What does this all mean? Well, basically the shorter the interval you use, the slower the timelapse appears to progress. For example, if you filmed a sunset using the 2 second interval, and then the 10 second interval, in the 2 second one the sun would move much slower. You would also capture more detail, like people moving by and birds flying etc.

It ultimately comes down to how much space you have in your camera memory, and how long the batteries in the camera will last.

For your first timelapse, I advise you use the 10 second setting, just because its simplest. This is the default ratio which you should have if you built it properly in the previous step.

To change ratios:

To change to either the 2 or 5 second interval:

Photo 1: Change the rod to look like this. If you turn on the motor now, the yellow gear should move but not the rocker arm.

Photo 2: This is for the five second interval. Loop an elastic band around the pulleys as shown. Now, if you turn on the motor, the rocker should move about every 5 seconds.

Photo 3: For the 2 second ratio, put the band between these two pullets but loop it round 180 degrees so it turns the cam in the right direction.