Fig. 3
From: Design and implementation of a simple and inexpensive respiratory synchronization control platform
TOP: Enhancement of the program shown in Fig. 2 recorded to additionally produce two electrical digital status outputs, first a 5-V level on Pin 7 during inspiration (and zero volts during expiration) and also a 5-V level on Pin 8 during expiration (with zero volts during inspiration). BOTTOM: Strip chart recording of Arduino UNO Pins 7 and 8 obtained using the DATAQ DI-1100 data acquisition system. The top graph is a plot against time of the inspiratory control signal, while the bottom graph is for the expiratory control signal. The software package supporting the strip chart system is by DATAQ. Known as WinDaq, it is available for free download to users of their data acquisition systems, with some USB-based data acquisition systems priced well under 100 dollars US (e.g., Model DI-1100)