##Introduction##
To get the cameras to trigger simultaneously, we chose to trigger them via USB using a feature of the CHDK.
##Assembling the 555 circuit##
* Pretty good instructions come in the 555 timer package
* Potentiometer confusion
* Stripping and attaching the USB cables
![Battery "hack"](https://publiclab.org/sites/default/files/imagecache/default/IMG_0033.JPG)
----
##Connecting the batteries##