The headline How to Make Time Lapse Video With Your DSLR didn’t really grab us. Honestly, you pay that much for a camera and it can’t do time lapse out of the box? Well, we nearly missed the real story: [Chris Martino] was using a TI-83 to act as the intervalometer for the camera. The calculator has a 2.5mm audio jack for it’s data port and the camera has an identical port for the shutter trigger. The TI-83 runs a program with a FOR loop to act as the timer. When the loop completes it sends data to the port, and the voltage triggers the shutter. The rate isn’t very exact and varies depending on the charge left in the batteries. [Chris] estimated 10000 program iterations ends up being about 26 seconds between pictures. This technique has been tested on 84, 86, and 89 series calculators too. There are a couple example time lapse videos embedded after the break.