Yesterday, Ryan, Trevor, and I met briefly to try out the trigger. It works!
We had to change some settings in the CHDK menu, and used this wiki page to learn about our options. We will have to change more settings next week when the rest of the electronics parts arrive. We’re hoping to use USB hubs so we can have the switch trigger both cameras at the same time while having them also hooked up to the computer for uploading photos.
We also thought about the placement of the trigger on the bookscanner–it should fit well right next to the handle, and we’re thinking about options for attaching it–maybe Velcro? Stay tuned for more electronics next week!