Hi all,
I have a negative scanner where I have to manually forward the negative holder each time a frame is done.
I'm thinking of using a Teensy and stepper motor to forward the negative holder after a scan is done and then let the computer scan the next frame using a keyboard shortcut.
I'm currently thinking of ways to detect whether the scanner is running using an Arduino/Teensy. Unfortunately, the scanner (A Plustek 8100) does not have an indicator light that blinks when done scanning or something. It's connected using a USB cable to the computer and uses its own 12V power supply.
The options I was thinking about:
-Put a piezo on the scanner to measure vibration when the scanner is running, might be susceptible to playing music or other vibrations.
-Interupting the 12V DC power supply and measuring a drop in voltage when the scanner is running. Could I do this directly using a voltage divider and ADC on Teensy?
-Maybe some kind of circuit where the Arduino is able to read the signals over USB between scanner and computer without interupting there communication?
Curious about your suggestions!