I'm making a posture control experiment in which a series of images (stimuli) are presented to a person and I'm trying to measure the displacement of this person as a result of these stimuli. To do so I'm planning to use 3 Arduinos:
1) "Arduino Tx 1": an Arduino nano with an Xbee shield and an MPU unit attached for sensing displacement. This implementation has to be wireless because the subject must be able to move freely.
2) "Arduino Tx 2": an arduino uno for reading an analog signal that indicates when an image (stimulus) is presented to the person
3) "Arduino Rx": an arduino uno connected to a computer and reading data from both "Arduino Tx 1" and "Arduino Tx 2"
I want to make sure that signals coming from "Arduino Tx 1" and "Arduino Tx 2" are synchronised. That is: if an image is presented at t=t0 (signal sensed by "Arduino Tx 2") then I want to be able to tell that the displacement sensed by "Arduino Tx 1" at t=t0+dt corresponds to this stimulus.
My question is: is it possible to ensure that signals coming from "Arduino Tx 1" and "Arduino Tx 2" are synchronised when read by "Arduino Rx"?