a platen-down contact switch may be useful

On Apr 9, 2008, at 8:20 AM, Gabe Juszel wrote:

I forget if it was Steve or Raj that hinted at the possibility of a
sensor in/at the registration blocks so either, camera will not
fire if glass is not flush or if it is flush, it triggers the shutter.

We notice (sometimes) being on repeat mode of 6 secs actually
lags a bit - and manully hitting a key for "Last button pressed"
will work better and faster.

Basically here is a recreation of a simple dowel that assisted in
the scanner, scanning books at a faster rate.

It may be a good idea to explore some automated/ flush
registration block trip wire for the camera's.